FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: blykins on December 30, 2020, 10:14:56 AM
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After the last dyno session on the 352, I sent the heads to Joe Craine to have them ported. Joe was able to pick them up over 40 cfm, which should net some nice gains the next time we make some pulls on it.
On disassembly, I saw where we were getting some fretting from the rocker stands moving around on the 1-piece stand shims.
(https://live.staticflickr.com/65535/50701997368_8e06c91a50_z.jpg)
I was running 280 lbs seat pressure and about 670 lbs open, which starts to tax the factory 4-stud mounting system. Obviously, things were moving around at rpm. Fortunately, I was able to prove the function and reliability of my non-adjustable roller rockers as they held up perfectly.
I knew that Joe was going to dress up the valve job and the valves would probably sink a hair. It was an exercise in patience to nail the lash on all 16 valves with non-adjustable rockers. I also knew that I'd likely have to order another set of pushrods and since there was no reason to test my non-adjustable rockers again, I bit the bullet and ordered a set of T&D street rockers.
So the task at hand was to address the fretting with the T&D's, since their street rockers use the factory mounting system.
I had found a weak thread in the factory heads while assembling the engine the first time and had to helicoil a hole. This time, I just went ahead and put in some thick inserts in all 8 holes.
(https://live.staticflickr.com/65535/50779433006_e4e0c30eac_z.jpg)
In my mind, that eliminates any weak issues with the factory bolt/stud holes.
The next task was to keep the stands from squirming around. I thought about pinning them then thought it would be easier to tighten up the fit in the stand hole. As they sit, the hole is pretty sloppy around the stud:
(https://live.staticflickr.com/65535/50778666073_326caa0eb8_z.jpg)
The way that I addressed this is to counterbore the bottoms of the T&D stands, then press a bushing in. The bushing had to be reamed to size, so it would have just enough clearance to slide on the stud:
(https://live.staticflickr.com/65535/50778666243_9155299aed_z.jpg)
There's a shadow around the stud in the picture. It's a pretty snug fit but allows the stud to slide in and out.
After that, I reassembled the T&D assemblies and since the kit was for a MR head, I re-arranged the rocker spacing.
I feel that this will tighten everything up considerably, but I'll know for sure after the next dyno session. Between the bushing locating the stand on the stud and the clamping force from the washer/nut at the top, it should add a lot of rigidity.
I would have already had the heads back on the short block this morning, but I'm out of 5/16" valve stem seals and had to order some. They'll be back on before the week's over.
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Nice idea.
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Forgive me if this a rookie question, but what keeps one from increasing the size of the fastener?
Seems it would be much stronger in all aspects and well easier. What am I missing?
Ive never had anything badass enough to have to face this issue head on so excuse my ignorance.
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Forgive me if this a rookie question, but what keeps one from increasing the size of the fastener?
Seems it would be much stronger in all aspects and well easier. What am I missing?
Ive never had anything badass enough to have to face this issue head on so excuse my ignorance.
The holes in the shafts would be the limiting factor.
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Yep, duh. Just dawned on me.
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I wonder how hard they'll be to put back on as a unit? The looser fit allows the stands to self align with the shafts. I'd assume that the stud holes aren't perfectly aligned, so it may be a bit of a booger to get them all to slide on. I know what assumptions can do, but so few things are machined perfectly from the factory. Not at all saying it's a bad idea, just that it might cause a different issue for you.
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I shouldnt be messing with this but why not pin the stand to the head?
Wouldnt that really keep things in place.
I have been taught that fastener (bolt)clamps things together and the friction of the surfaces should keep things together not the bolts sides.
Iwe done machining jigs same way that the bolt alings things but rocker fretting seems wrong place for that.
Im not saying that dosent work just ive been taught to think difrent way.
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To the guys questioning the utility of locating this way, you have 16 rod bolts and 4 head bolts that use the same theory, it is particularly applicable to the rod caps, which are located either by this method or by the shank of a bolt
In fact, many main caps are "pinned" this way as well, although factory FEs generally do not do it, it is a proven and simple way to locate something
Personally, I think it's very clever, and when adding the thread inserts, its also a logical time to correct the location of the holes if they measure wrong but my gut tells me there is a little more play in the fore and aft dimensions, it would be the left and right (toward intake or exhaust) that would be tougher to manage and require correction to stay on shaft centerline.
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I wonder how hard they'll be to put back on as a unit? The looser fit allows the stands to self align with the shafts. I'd assume that the stud holes aren't perfectly aligned, so it may be a bit of a booger to get them all to slide on. I know what assumptions can do, but so few things are machined perfectly from the factory. Not at all saying it's a bad idea, just that it might cause a different issue for you.
Not bad at all. They don’t fall on but I haven’t had to get the 3 lb hammer out either.
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Would there be enough thread in the head to machine a recess at the top portion and have a longer bushing that would register in the recess of the head and the stand?
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The springs are pretty hefty, for the rpm level, that your at now, with those valves. I assume your going to raise that, at some point?
Do you have the same issue on your higher rpm builds or just this one?
Personally, I think this issue is caused from a bending moment, if so, I don't think it will help, in the long run. The soft bushing will also fret.
As Greg is suggesting, a harden steel bushing (.500x.375x.625 Lg) might be worth a try, pressed into the head, at least 1/4" and slip fit in the stand.
7/16 bolts/studs would also help, you'd only have to enlarge the shaft holes accurately and open the stand holes.
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Which brand of shaft stands are those? The set I have from Survival has a small countersink on the top side for the washer and nut to index onto. I can't tell if there's one on these photos.
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Which brand of shaft stands are those? The set I have from Survival has a small countersink on the top side for the washer and nut to index onto. I can't tell if there's one on these photos.
They're T&D.
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The springs are pretty hefty, for the rpm level, that your at now, with those valves. I assume your going to raise that, at some point?
Do you have the same issue on your higher rpm builds or just this one?
Personally, I think this issue is caused from a bending moment, if so, I don't think it will help, in the long run. The soft bushing will also fret.
As Greg is suggesting, a harden steel bushing (.500x.375x.625 Lg) might be worth a try, pressed into the head, at least 1/4" and slip fit in the stand.
7/16 bolts/studs would also help, you'd only have to enlarge the shaft holes accurately and open the stand holes.
There's a lot more to spring pressure than the rpm and valve sizes. The cam has the most bearing on that. An aggressive lobe needs a lot more spring pressure than a lazy one.
I don't have this problem on higher rpm builds because I usually use T&D race rockers, which use the head bolts to fasten everything down. On this engine, I wanted to give my non-adjustable rockers a beating, so I used Harland Sharp shafts and POP stands/end stands. It's certainly not a bending moment, the stands are just moving, the same as a main cap will move and fret.
The only other engine I've seen it on was a solid roller tunnel port, which had T&D street rockers. It fretted the stands as well. However, you can't easily convert the tunnel port heads to T&D race rockers, so it was either a good street rocker, or change to a flat tappet with less spring pressure.
I think this will work just fine. More than one way to skin a cat, but this one makes sense to me and we'll know after the dyno.
The dowel in the head isn't a bad idea, unless there would be an issue with the hole where the oil comes up.
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I wonder how hard they'll be to put back on as a unit? The looser fit allows the stands to self align with the shafts. I'd assume that the stud holes aren't perfectly aligned, so it may be a bit of a booger to get them all to slide on. I know what assumptions can do, but so few things are machined perfectly from the factory. Not at all saying it's a bad idea, just that it might cause a different issue for you.
Not bad at all. They don’t fall on but I haven’t had to get the 3 lb hammer out either.
Good deal. It'll be interesting to see how well it works, although at that level people are probably better off with the T&D setup.
7/16 bolts/studs would also help, you'd only have to enlarge the shaft holes accurately and open the stand holes.
Opening up the shaft holes would be a really bad idea. The shafts are already significantly weakened by the existing holes. Enlarging them is inviting failure.
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Brent,
How about a really revolutionary approach? A "bed plate" ( similar to a Jessel/T&D SBC) with "half stands" machined into the plate and a two bolt cap to secure the shaft itself. The bed plate could be steel and have the end support incorporated. The plate could be held down with Jessel/T&D 7/16ths "short" bolts and a cap held on with two 5/16ths bolts. The holes in the shaft could be reduced as well as the ID of the through hole in the shaft seriously improving strength. It could be made to fit stock or aftermarket rockers. A small oil passage could be put into the plate for shaft oiling.
If my father in law (rip) was still here I would have him make a set to demonstrate the concept.
Randy
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Opening up the shaft holes would be a really bad idea. The shafts are already significantly weakened by the existing holes. Enlarging them is inviting failure.
I thought about that but, the shafts are fully supported on both sides, by the stands. I don't think there would be any issue, especially with after market shafts.
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I wonder how hard they'll be to put back on as a unit? The looser fit allows the stands to self align with the shafts. I'd assume that the stud holes aren't perfectly aligned, so it may be a bit of a booger to get them all to slide on. I know what assumptions can do, but so few things are machined perfectly from the factory. Not at all saying it's a bad idea, just that it might cause a different issue for you.
Not bad at all. They don’t fall on but I haven’t had to get the 3 lb hammer out either.
Good deal. It'll be interesting to see how well it works, although at that level people are probably better off with the T&D setup.
7/16 bolts/studs would also help, you'd only have to enlarge the shaft holes accurately and open the stand holes.
Opening up the shaft holes would be a really bad idea. The shafts are already significantly weakened by the existing holes. Enlarging them is inviting failure.
I think it's a bad idea too. Depending on the shaft, there's not a lot of meat left there. In addition, if you were to try it, you'll find that the shafts are extremely hard.
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Brent,
How about a really revolutionary approach? A "bed plate" ( similar to a Jessel/T&D SBC) with "half stands" machined into the plate and a two bolt cap to secure the shaft itself. The bed plate could be steel and have the end support incorporated. The plate could be held down with Jessel/T&D 7/16ths "short" bolts and a cap held on with two 5/16ths bolts. The holes in the shaft could be reduced as well as the ID of the through hole in the shaft seriously improving strength. It could be bade to fit stock or aftermarket rockers. A small oil passage could be put into the plate for shaft oiling.
If my father in law (rip) was still here I would have him make a set to demonstrate the concept.
Randy
More than one way to skin a cat. As Doug said, for any hipo setups, we usually just reach for T&D paired rockers and bypass all the worry. However, I'm cheap and thought this would be a rather economical solution since I already had the parts and didn't want to go milling my heads down.
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You might want to seal one of the holes where it goes into the hump on one head. The porting left a very thin area under the hole that may break through and leak oil into the port when running. Just remembered that while reading this. The port flowed was the one with the bump, so the actual flow in the other ports should be better. Hope the 352 is no longer considered PJJ. Joe-JDC
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In addition, if you were to try it, you'll find that the shafts are extremely hard.
A carbide end mill or a carbide tipped drill, will go right threw it. End mill, preferred, it won't go off center and you can correct any hole inaccuracy that way, too.
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Joe, how much of the hump do you leave?
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Depends on the customer. Some folks want it all removed and will use a sealant on the rocker stud, and others I try to work it down until I get very close to the hole as measured with caliper. Some heads have the hole on that stud drilled and tapped a bit more than others. Careful measurement is the key to not breaking through. You break through where you least expect the hole to be in the hump. It is not centered. Joe-JDC
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I wonder how hard they'll be to put back on as a unit? The looser fit allows the stands to self align with the shafts. I'd assume that the stud holes aren't perfectly aligned, so it may be a bit of a booger to get them all to slide on. I know what assumptions can do, but so few things are machined perfectly from the factory. Not at all saying it's a bad idea, just that it might cause a different issue for you.
Not bad at all. They don’t fall on but I haven’t had to get the 3 lb hammer out either.
Good deal. It'll be interesting to see how well it works, although at that level people are probably better off with the T&D setup.
I have done a similar modification. I installed the heavy wall inserts in the heads and had some custom stands made to address the bolt hole tolerance that Brent showed a picture of. I started with a set of Erson rockers. I went with the heavy duty shafts from DSC. I noticed the sloppy bolt holes in the original stands. I found out my stands needed to be raised .030" to get geometry in check. So, to address the holes and shimming, I had a local machinist make me some new stands to my specs. out of 7075. The holes are centered exact 4.630" and finish reamed to .375". I tried mocking the stands up with the studs already in the heads and it didn't matter if they were loose or snugged, it was too close of a fit to slide the assembly down. So, I have the studs with nuts already installed through the shafts/stands and drop the whole assembly down and carefully start each one. A little patience and they all go.
During mockup in the pics below I test fit the assemblies on the heads and with just the studs snugged in the heads and no washers/nuts on top, I could grab each end of the shaft and the whole engine would move on the stand before I could get even a wiggle out of the stands. I figured at this point, it should be good enough.
(https://i.postimg.cc/br6zdTtT/20190804-174342.jpg) (https://postimages.org/)
(https://i.postimg.cc/ZYjYfTMd/20190804-174414.jpg) (https://postimages.org/)
This setup currently has about 500mi on it and quite a few trips to 7500rpm. I pulled the rockers off a month ago for hibernation purposes and checked the bottom of the stands and head surfaces. I saw no signs of fretting thus far...
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7/16 bolts/studs would also help, you'd only have to enlarge the shaft holes accurately and open the stand holes.
Opening up the shaft holes would be a really bad idea. The shafts are already significantly weakened by the existing holes. Enlarging them is inviting failure.
Not to mention if you are oiling through the heads, the oil has to make it around the mounting studs/bolts. If you run larger fasteners, you may starve some of the rockers for oil. I noticed on the thick wall Erson shafts from DSC, there is not a lot of clearance for the oil to go around the fastener. I looked through the shaft with a stud through the hole and a light shining from the other end and didn't see much light, lol.
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... I figured at this point, it should be good enough.
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That's a remarkable engineering exercise.
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I wonder how hard they'll be to put back on as a unit? The looser fit allows the stands to self align with the shafts. I'd assume that the stud holes aren't perfectly aligned, so it may be a bit of a booger to get them all to slide on. I know what assumptions can do, but so few things are machined perfectly from the factory. Not at all saying it's a bad idea, just that it might cause a different issue for you.
Not bad at all. They don’t fall on but I haven’t had to get the 3 lb hammer out either.
Good deal. It'll be interesting to see how well it works, although at that level people are probably better off with the T&D setup.
I have done a similar modification. I installed the heavy wall inserts in the heads and had some custom stands made to address the bolt hole tolerance that Brent showed a picture of. I started with a set of Erson rockers. I went with the heavy duty shafts from DSC. I noticed the sloppy bolt holes in the original stands. I found out my stands needed to be raised .030" to get geometry in check. So, to address the holes and shimming, I had a local machinist make me some new stands to my specs. out of 7075. The holes are centered exact 4.630" and finish reamed to .375". I tried mocking the stands up with the studs already in the heads and it didn't matter if they were loose or snugged, it was too close of a fit to slide the assembly down. So, I have the studs with nuts already installed through the shafts/stands and drop the whole assembly down and carefully start each one. A little patience and they all go.
During mockup in the pics below I test fit the assemblies on the heads and with just the studs snugged in the heads and no washers/nuts on top, I could grab each end of the shaft and the whole engine would move on the stand before I could get even a wiggle out of the stands. I figured at this point, it should be good enough.
(https://i.postimg.cc/br6zdTtT/20190804-174342.jpg) (https://postimages.org/)
(https://i.postimg.cc/ZYjYfTMd/20190804-174414.jpg) (https://postimages.org/)
This setup currently has about 500mi on it and quite a few trips to 7500rpm. I pulled the rockers off a month ago for hibernation purposes and checked the bottom of the stands and head surfaces. I saw no signs of fretting thus far...
Looks good. I did the “wiggle test” earlier as well. Should work fine.
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... I figured at this point, it should be good enough.
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That's a remarkable engineering exercise.
I'm no rocket surgeon. Sometimes things look good on paper, but until you give it a look and a good shake/wiggle and can conclude with "Yep, that ain't going anywhere", THEN you know.
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What I wonder about is the clamping force with the rocker supports not slotted. The Ford FE Hipo stands were slotted am told so that they clamp down on the shaft, basically making sure everything is stacked up and solid so the clamp force is against something solid. Without that slot have to wonder if the rocker support acts a bit like a spring having to be deformed to stack up solid against the shaft. Just a thought. Nice work!
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Heads are back on, new pushrods ordered. The T&D's sit lower than my rockers, so the pushrod length changed. No biggie.
Rockers fit really well and I'm pleased with them. Seems like I have to leave one stud out when they go on and even then they are a hair snug but I can work them down. I gave them the nightmist66 test and all I can do is move the engine on the stand, even with the washers/nuts off.
(https://live.staticflickr.com/65535/50788264757_99961e224e_z.jpg)
(https://live.staticflickr.com/65535/50788157381_bb3a301cbf_z.jpg)
(https://live.staticflickr.com/65535/50787402083_c802b1fa1f_z.jpg)
Can't put the intake on until I recheck pushrod tube clearance but it won't be too long before it's making noise again.
Thinking down the road, after this next iteration, I'm going to order another set of pistons and aim for about 12.5:1 compression. My guess is that will add about 40-45 hp on top of what it will make with the ported heads. I'd really like to end up pushing around 600 hp with it.
I also have dreams of Hilborn mechanical injection or maybe even a Tunnel Ram. Sigh.
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When I preoiled my motor the oil wasn’t coming up to the shaft on one side. Had to machine down stud a few thousandths and was good. I wonder if you might have problems with the tight fit. Just throwing it out there
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I typically oil through the pushrods on my engines.
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Ya know I forgot that that’s one of your things.
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I have done a similar modification. I installed the heavy wall inserts in the heads and had some custom stands made to address the bolt hole tolerance that Brent showed a picture of. I started with a set of Erson rockers. I went with the heavy duty shafts from DSC. I noticed the sloppy bolt holes in the original stands. I found out my stands needed to be raised .030" to get geometry in check. So, to address the holes and shimming, I had a local machinist make me some new stands to my specs. out of 7075. The holes are centered exact 4.630" and finish reamed to .375". I tried mocking the stands up with the studs already in the heads and it didn't matter if they were loose or snugged, it was too close of a fit to slide the assembly down. So, I have the studs with nuts already installed through the shafts/stands and drop the whole assembly down and carefully start each one. A little patience and they all go.
During mockup in the pics below I test fit the assemblies on the heads and with just the studs snugged in the heads and no washers/nuts on top, I could grab each end of the shaft and the whole engine would move on the stand before I could get even a wiggle out of the stands. I figured at this point, it should be good enough.
(https://i.postimg.cc/br6zdTtT/20190804-174342.jpg) (https://postimages.org/)
(https://i.postimg.cc/ZYjYfTMd/20190804-174414.jpg) (https://postimages.org/)
This setup currently has about 500mi on it and quite a few trips to 7500rpm. I pulled the rockers off a month ago for hibernation purposes and checked the bottom of the stands and head surfaces. I saw no signs of fretting thus far...
That's a really nice job, Jared. Every aspect of your engine is well thought out.
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Jared ,
My "vision" is similar to what you have made. The "stands" would have to be wider on the four places where the studs are and have a "removable "cap" so a bolt could be used to hold the stand to the head instead of the stud and then the cap could be bolted on with two 1/4 or 5/16ths bolts.
Randy
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A saddle is a beautiful thing, but I'd bet good money that they are done moving, and in a much more cost effective way. The area on the external face of a cylinder (the bushing) is significant and locates in multiple axes and even torsional.
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What if you pinned the stands, but put the pins in at an angle, like 45 degrees. Obviously the pins would have to all go the same direction, but it would locate on an axis not parallel to the main stress.
Just a thought,
pl
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What if you pinned the stands, but put the pins in at an angle, like 45 degrees. Obviously the pins would have to all go the same direction, but it would locate on an axis not parallel to the main stress.
Just a thought,
pl
My opinion, try to knock over a cup, then put it in a tight cup holder. The bushing Brent made is locating left/right/front/back on the machined surfaces and captured by the stud, on top of that it is acting like the cup in the cup holder too against twisting as it unloads and loads.
I am not sure how you'd assemble with a 45 degree pin, but regardless, any way you pin it will be better, but the bushing idea is extremely simple and durable. If it still moved at all I would be amazed, but if it did, I would only go deeper into each piece slightly and make the bushing out of something harder, but the concept is effective and sound. Mentioned it before, but think about the incredible beating a capscrew connecting rod gets and all it has is a little steel bushing, much like Brents
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On rods, the alignment is on both sides (rod & cap) and it is only to align both sides, stock type rod bolts do what brent has done but, it appears that he has used a Oilite type bushing material (sintered bronze) and porous metal. To me, it's hard to say there is no bending moment, when you have a 1.76 lever from the valve, a couple of inches, above the threaded hole.
Another idea would be to make the stands out of 4140, HT steel bar stock and make a integral, hollow dowel pin, at the base, 1/2 to 5/8 diameter. Vertically slot the the for the oil hole.
I like Jared's too. He needs to sell his design to one of the FE suppliers.
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On rods, the alignment is on both sides (rod & cap) and it is only to align both sides, stock type rod bolts do what brent has done but, it appears that he has used a Oilite type bushing material (sintered bronze) and porous metal. To me, it's hard to say there is no bending moment, when you have a 1.76 lever from the valve, a couple of inches, above the threaded hole.
Another idea would be to make the stands out of 4140, HT steel bar stock and make a integral, hollow dowel pin, at the base, 1/2 to 5/8 diameter. Vertically slot the the for the oil hole.
I like Jared's too. He needs to sell his design to one of the FE suppliers.
There will always be some kind of bending moment, no matter what design. Even on Jared's stands, there will be a bending moment and it will occur about the face where the stand meets the head. Kinda hard to get around that sort of thing, that's why stud girdles on conventional stud mounted rockers help so much.
We are trying to eliminate any movement of the stand on the cylinder head with this design. With these setups out of the box it's easy to move the stands around on the studs. You can't now.
I've always been more concerned about pulling the studs out of the heads more than the stands moving, but when I see marks like that on the shims, I wanted to try and see if I could eliminate it. If the stands are moving, then the shaft is deflecting and that's not good. It would have lived before (if the threads in the heads stayed intact) and I'm confident it will be just fine now as well.
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From my reply #10:
Personally, I think this issue is caused from a bending moment
From your reply #13:
It's certainly not a bending moment
From your reply above:
There will always be some kind of bending moment, no matter what design.
So are we in agreement then?
Where the failure will probably occur, will be at the minor thread diameter of the 3/8 x 16 thread. A 38 x 24 thread, in the insert, would help in that area and give a little tension, also.
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On rods, the alignment is on both sides (rod & cap) and it is only to align both sides, stock type rod bolts do what brent has done but, it appears that he has used a Oilite type bushing material (sintered bronze) and porous metal. To me, it's hard to say there is no bending moment, when you have a 1.76 lever from the valve, a couple of inches, above the threaded hole.
Another idea would be to make the stands out of 4140, HT steel bar stock and make a integral, hollow dowel pin, at the base, 1/2 to 5/8 diameter. Vertically slot the the for the oil hole.
I like Jared's too. He needs to sell his design to one of the FE suppliers.
I don't agree at all, well except that I like Jared's, I agree it's a nice design, but could be overkill
1 - Rods have angular loads and then change directions, the changing of direction is significant, and if you don't like rod analogy because it doesn't load and unload , think mains that do the same, this type of pin works the same way and main caps can fret too and this design fixes it. It is being unloaded and loaded from side to side and on different ends, just like this.FEs don't use the collared pin, but other caps do. Regardless, if you don't like either analogy, it isn't important anyway, it's countering the cause of the movement that is important not just what it may or may not be like.
2 - IMHO, the lever you talk about doesn't exact that type of force on the stand and the primary vector is upwards. You have a pushrod trying to go up on one side, and a valve/spring trying to stay up on the other side, which puts the pressure upwards on the shaft. Because that the majority of the vector is upward with sort of a rocking oscillation. What I think we see with the fretting is the loading and unloading causing harmonics which causes the movement of the stands and slight movement within the slop of the bolts. A small pin, or this type of fix is likely all that is needed up to a very high rpm.
I do not believe it is a resistance to pressure requiring bracing, I think it is a transfer of oscillation into the larger head that controls it. Of course both designs do it, but one does very simply.
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Ross, what is causing this?
The majority of the vector of both is upward with sort of a rocking oscillation.
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Frank, the rocking is cause by the loading and unloading of the rocker.....and fretting is because it's bolted onto a flat surface. Once the surface has anything plunged, the surface area of the side of the tight fitting bushing and the inability for it to rock will dissipate the harmonics.
Maybe Bill Conley can model it? But I really don't think this thing needs a girdle for that
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That's a really nice job, Jared. Every aspect of your engine is well thought out.
Much, much too kind. Mediocre at best compared to the pro's. I have been fortunate to speak to a couple individuals much smarter than I and discuss some of my stupid ideas.
Jared ,
My "vision" is similar to what you have made. The "stands" would have to be wider on the four places where the studs are and have a "removable "cap" so a bolt could be used to hold the stand to the head instead of the stud and then the cap could be bolted on with two 1/4 or 5/16ths bolts.
Randy
Randy, I can visualize exactly what you mean. However, I feel that the fastener and width/contact area of the base of the stand will have the last say. Maybe I'm missing something, but I'm not sure if the straddled faster cap will add anymore rigidity. I say this with no certainty. I have ZERO engineering background. Just a shadetree'r.
I like Jared's too. He needs to sell his design to one of the FE suppliers.
'Tis not my design. It is the same basic design as the original stands from Erson. All I did is tighten up some clearances and put a couple of my own small touches on it.
I don't agree at all, well except that I like Jared's, I agree it's a nice design, but could be overkill
If some is good, more is better, and too much is just enough.
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There will always be some kind of bending moment, no matter what design. Even on Jared's stands, there will be a bending moment and it will occur about the face where the stand meets the head. Kinda hard to get around that sort of thing, that's why stud girdles on conventional stud mounted rockers help so much.
Not sure how much "bending" would be applied in either of our setups. If the stand holes are are tight to the stud, as ours are now, then the stands and studs are almost one with each other. The only place I can visualize the flex happening after that point would be the stud portion threaded into the head below the stand surface and the stud above the stand surface. If we are using a good quality fastener, such as ARP with high tensile strength, precision ground washers, perpendicular threads and flange on the nut and a good flat or spotfaced area on the top of the stand, then I find it hard to believe that any or much flex exists there if the fastener maintains it's respective torque value. The only other place I see the flex would be allowed is the base of the stand or somehow the material in the head is "compressing". In either case, you should see some kind of witness after taking place, such as stress cracks possibly in the stand or unevenness in the stand boss cast in the head like a small ledge. I don't know if I can explain clear enough what I'm trying to say.
The stud mount rockers do benefit from a girdle. This is essentially what we are achieving in our setups by tightening the bolt hole tolerance. The force on the studs is directly applied to the stand, which is directly applied to the head with a much larger "footprint" than the stud alone. I think the "double stand" setup like the Erson is somewhat like a mini girdle. I dunno. Hope I haven't derailed this thread too much.
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I think it’s a good conversation, many ways to fix a problem
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Frank, the rocking is cause by the loading and unloading of the rocker.....and fretting is because it's bolted onto a flat surface. Once the surface has anything plunged, the surface area of the side of the tight fitting bushing and the inability for it to rock will dissipate the harmonics.
Maybe Bill Conley can model it? But I really don't think this thing needs a girdle for that
The definition of "rocking", although there is nothing "gentle" about 670 lb. Underlines are mine:
rocking
noun
1. the action of moving or being moved gently to and fro or from side to side: "I was lulled to sleep by the rocking of the ship"
adjective
1. moving gently to and fro or from side to side: "the rocking movement of the boat"
Rocking is produced, when one side has more weight than the other and leverage produces the extra weight if, one side has more leverage than the other.
I too, would love to see a model.
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From my reply #10:
Personally, I think this issue is caused from a bending moment
From your reply #13:
It's certainly not a bending moment
From your reply above:
There will always be some kind of bending moment, no matter what design.
So are we in agreement then?
Where the failure will probably occur, will be at the minor thread diameter of the 3/8 x 16 thread. A 38 x 24 thread, in the insert, would help in that area and give a little tension, also.
No, we are not in agreement in that statement, because you selectively quoted me.
My quote was: "It's certainly not a bending moment, the stands are just moving, the same as a main cap will move and fret."
Your point was that a bending moment *caused* the movement. My reply was no, a bending moment didn't cause the movement, the stands are moving because of sloppy holes.
I believe you're confusing "bending moment" with a vectored force. A bending moment in this small system of rocker arm stand to cylinder head would be the overall force of the pushrod/rocker arm interaction trying to bend the stand stud. With a substantially made stud that's correctly fixed to the head, this is minimalized.....maybe even brought almost to zero, but I think that it's still there. The vectored force is what's giving us the problem. Any vectored force at an angle will have a Y component and an X component. The X component is what is trying to push the stands sideways. When the stand is positively located, then that translation should be brought to minimum as well.
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Frank, the rocking is cause by the loading and unloading of the rocker.....and fretting is because it's bolted onto a flat surface. Once the surface has anything plunged, the surface area of the side of the tight fitting bushing and the inability for it to rock will dissipate the harmonics.
Maybe Bill Conley can model it? But I really don't think this thing needs a girdle for that
The definition of "rocking", although there is nothing "gentle" about 670 lb. Underlines are mine:
rocking
noun
1. the action of moving or being moved gently to and fro or from side to side: "I was lulled to sleep by the rocking of the ship"
adjective
1. moving gently to and fro or from side to side: "the rocking movement of the boat"
Rocking is produced, when one side has more weight than the other and leverage produces the extra weight if, one side has more leverage than the other.
I too, would love to see a model.
Frank we are in danger of transitioning to a stalemate like other posts
- The saddle/girdle will work just fine that others have mentioned, within any limitations it may end up having in design, like any other developmental piece
- There is no doubt in my mind Brent's solution will work also, and , for the level of force inflicted on those pieces, I will not be convinced otherwise unless testing proves it.
If you like the more saddled design, build a set and have some fun on the Edsel or sell them. Building an engine isn't binary, and designs aren't either, many ways to skin a cat, many ways to reliably make power.
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That's a really nice job, Jared. Every aspect of your engine is well thought out.
Much, much too kind. Mediocre at best compared to the pro's. I have been fortunate to speak to a couple individuals much smarter than I and discuss some of my stupid ideas.
That's a really mediocre job, Jared. Every aspect of your engine is moderately thought out.
There, I fixed it ;D
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What if...making a threadinserts with a Dovel/bushing whatever to call it sticking up from the head
and counterbore the stand for a snug fit around that dovel?
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The rocker stands are moving because there is not enough clamping force to hold them in place. All been done here is try to limit the hula hoop movement which cannot hurt the situation. How well it will work guess see, I'd say will still fret, but a lot less. Real problem is the design. Four poorly placed 3/8" bolts is weak spot in the FE design.
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The rocker stands are moving because there is not enough clamping force to hold them in place. All been done here is try to limit the hula hoop movement which cannot hurt the situation. How well it will work guess see, I'd say will still fret, but a lot less. Real problem is the design. Four poorly placed 3/8" bolts is weak spot in the FE design.
I think if clamping force was the culprit then nightmist66 would still be seeing fret marks.
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Why not a stepped stud. 7/16 bottom transitioning to 3/8 before the rocker shaft?
More thread engagement with parent material and larger cross section at the head/stand mating area.
Pretty sure they are readily available and would be simpler and stronger then any head insert. Possibly cheaper
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Brent and Ross, I think your trying to "bend" the laws of physics to try to prove me wrong.
Brent, so you say I selectively quoted you? Here is your complete thought:
There will always be some kind of bending moment, no matter what design. Even on Jared's stands, there will be a bending moment and it will occur about the face where the stand meets the head. Kinda hard to get around that sort of thing, that's why stud girdles on conventional stud mounted rockers help so much.
I think you guys would rather jump into a vat of boiling oil, rather than agree with me, right?
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Brent and Ross, I think your trying to "bend" the laws of physics to try to prove me wrong.
Brent, so you say I selectively quoted you? Here is your complete thought:
There will always be some kind of bending moment, no matter what design. Even on Jared's stands, there will be a bending moment and it will occur about the face where the stand meets the head. Kinda hard to get around that sort of thing, that's why stud girdles on conventional stud mounted rockers help so much.
I think you guys would rather jump into a vat of boiling oil, rather than agree with me, right?
You selectively quoted me up above, where you made it look like I was contradicting myself. I wasn't and explained why.
There will be *a* bending moment there because *a* force is being applied there. As I stated above, it may be almost next to zero, but there will be *something*. However, that bending moment isn't causing the stand fretting. It's the horizontal component of the force being applied to the hindend of the rocker arm that's pushing it over.
We look at net forces in play and then see where those forces overcome the stability or strength of a component.
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Brent and Ross, I think your trying to "bend" the laws of physics to try to prove me wrong.
Brent, so you say I selectively quoted you? Here is your complete thought:
There will always be some kind of bending moment, no matter what design. Even on Jared's stands, there will be a bending moment and it will occur about the face where the stand meets the head. Kinda hard to get around that sort of thing, that's why stud girdles on conventional stud mounted rockers help so much.
I think you guys would rather jump into a vat of boiling oil, rather than agree with me, right?
Certainly funny if tongue in cheek, but I am not disagreeing, I am choosing not to play.
As I said, and will say one more time, I believe both designs will work, as a single .125 hardened pin straight down would too, and until someone shows me with testing that any one of those doesn't, a fitted collar plunged into the head and stand looks like a very efficient and effective way to fix it.
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A long stud has more potential for stretch than a short 1-1.500 bolt. That is why I suggested what I did. Aluminum dampens harmonics better than steel but Jessel and T&D use steel. I agree with Brent , "fretting" is the stand "dancing" up and down not just a "torsional" situation.
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Aw shucks, let's just weld them suckers.
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The rocker stands are moving because there is not enough clamping force to hold them in place. All been done here is try to limit the hula hoop movement which cannot hurt the situation. How well it will work guess see, I'd say will still fret, but a lot less. Real problem is the design. Four poorly placed 3/8" bolts is weak spot in the FE design.
I think if clamping force was the culprit then nightmist66 would still be seeing fret marks.
Nightmist setup is not the same and reduces the needed clamping force IMHO. Your trying to fix the weak factory setup by stabilizing it with that bushing, but as GT350H rightly commented below "fretting" is the stand "dancing" up and down." this is about what it comes down to and without changing how the force gets distributed like in Nightmists setup other than constraining the movement like your doing all is left is the holding force applied.
Anyway I'd like to see how what you did works, I'm sure it will improve the situation, just wonder how much. It could turn out to work well and hope it does given anything that can make the factory setup work better without big modifications is a plus.
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That's a really nice job, Jared. Every aspect of your engine is well thought out.
Much, much too kind. Mediocre at best compared to the pro's. I have been fortunate to speak to a couple individuals much smarter than I and discuss some of my stupid ideas.
That's a really mediocre job, Jared. Every aspect of your engine is moderately thought out.
There, I fixed it ;D
Better. :)
A long stud has more potential for stretch than a short 1-1.500 bolt. That is why I suggested what I did. Aluminum dampens harmonics better than steel but Jessel and T&D use steel.
Excuse the ignorance. That slipped my mind when I read it. I agree with that. I put a few extra pounds of torque on the short head studs for that reason.
The Harland Sharp setup uses steel stands if you buy the kit.
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Attempting to get back on track. Brent, did you bush the stand the whole length of the hole(top to bottom) or is it a short bushing in the bottom of the stand? I have mine tight top to bottom, hoping it would eliminate any flex or movement for the stud in the entirety of the stand.
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I always wonder why the Oregon Cams rocker support system isn't brought up during conversations like this. It seems to be a pretty stout system for using the stock 4 bolt set-up. The supports are much shorter, theoretically making them more stable, and they would be super easy to pin to the base, as has been brought up, which would probably help even more. If you had to raise or lower the base to get correct geometry, that would even be pretty easy.
Several guys have been using them for many years, and I've had a set on my Mach 1 for the last 6 years, with thousands of miles of use and no issues at all.
http://www.oregoncamshaft.com/428-FE.html
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I think if their stand holes are sloppy we are right back to where things can move.
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Doug, it appears on that Oregon Cams setup that the base, stands, and end stands are all individual pieces held together by fasteners?
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Doug, it appears on that Oregon Cams setup that the base, stands, and end stands are all individual pieces held together by fasteners?
The stands simply clamp the base when bolted down, but yes, the end supports are held by 2 allen head bolts. All they have to do is stop the end of the shafts from bending upward, which they do. The end supports are a tight fit, with even the allen head bolts being a rather tight fit through the ends. The base is one piece that is held down by the stands, so there are no more fasteners than any stock type system.
I'm not saying they will cure any issues, but the shorter stands, along with the solid base to help spread the load out, work quite well.
Brent, just going by memory, the stands did seem tighter on the bolts than typical aftermarket aluminum stands.
Sorry, I just don't get all the discussion and debate here. If someone is using enough spring pressure to have the stands start moving around, you're much better off with the race T&D system. If the engine is built to that level, why risk stuff with a cheaper system? The valvetrain is NOT where you want to save money at! You've obviously spent some serious money on the engine already (not directed at you, Brent), so bite the bullet and do it right. It just doesn't make sense to do it otherwise.
What Brent did seems like a sound idea, but he has easy access to the machining equipment to do it, and probably already had the tools for reaming to the proper size. He also isn't paying anyone for the labor. If you had to pay someone to do all the machining, the cost of the bushings, and pay to have them reamed, the price has to start climbing pretty significantly. I'm sure he has several hours in work invested. Add the original cost of the stands and spacers and I'd think you're well on your way to the purchase of the T&D system. Again, just talking about the average person who doesn't have a mill and reaming tools.
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Doug, it appears on that Oregon Cams setup that the base, stands, and end stands are all individual pieces held together by fasteners?
The stands simply clamp the base when bolted down, but yes, the end supports are held by 2 allen head bolts. All they have to do is stop the end of the shafts from bending upward, which they do. The end supports are a tight fit, with even the allen head bolts being a rather tight fit through the ends. The base is one piece that is held down by the stands, so there are no more fasteners than any stock type system.
I'm not saying they will cure any issues, but the shorter stands, along with the solid base to help spread the load out, work quite well.
Brent, just going by memory, the stands did seem tighter on the bolts than typical aftermarket aluminum stands.
Sorry, I just don't get all the discussion and debate here. If someone is using enough spring pressure to have the stands start moving around, you're much better off with the race T&D system. If the engine is built to that level, why risk stuff with a cheaper system? The valvetrain is NOT where you want to save money at! You've obviously spent some serious money on the engine already (not directed at you, Brent), so bite the bullet and do it right. It just doesn't make sense to do it otherwise.
What Brent did seems like a sound idea, but he has easy access to the machining equipment to do it, and probably already had the tools for reaming to the proper size. He also isn't paying anyone for the labor. If you had to pay someone to do all the machining, the cost of the bushings, and pay to have them reamed, the price has to start climbing pretty significantly. I'm sure he has several hours in work invested. Add the original cost of the stands and spacers and I'd think you're well on your way to the purchase of the T&D system. Again, just talking about the average person who doesn't have a mill and reaming tools.
And that pretty much sums it up. I use T&D race rockers on any engines that I build for customers with over 600 lbs open pressure. It's not even a consideration.
However, I'm cheap, it's my junk, and I didn't want to whack these C6 heads, so I'm giving this a shot. It may serve to be an option for someone on a budget sometime. We will see how it works. To be honest, the old system probably would have went right on (unless the threads in the head gave out at some point) but it's an exercise in the spirit of hot rodding.
I'm having more fun with this 352 than I ever thought. It showed its love for me after I bought it and showed it some care. I like underdog stuff. I'm gonna beat her on the dyno with the ported heads and I'm hoping it will let me see 500 hp. If I get to that point, then I have some other tricks further down the road. I'd really like to see this thing knock on the door of 600 hp with factory heads. Time will tell.
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I thought they looked like separate pieces Doug. Certainly a good design but Jared's appears to be all one piece that adds alot of strength.
Brent we are having fun watching as well. If you want, we have a TW and 660's right down the road that you can try for your next step up.
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Sorry, I just don't get all the discussion and debate here. If someone is using enough spring pressure to have the stands start moving around, you're much better off with the race T&D system. If the engine is built to that level, why risk stuff with a cheaper system? The valvetrain is NOT where you want to save money at! You've obviously spent some serious money on the engine already (not directed at you, Brent), so bite the bullet and do it right. It just doesn't make sense to do it otherwise.
I think we are all splitting hairs here. I mean that in a nice way and no disrespect to anyone. It has been an informative discussion so far. I feel for 80-90% of the setups out there with a flat tappet(solid or hyd.), hydraulic roller, or even a real mild solid roller that most of the rocker setups out there will handle the job just fine as is. Except for that cheap China stuff. That junk is just junk, lol. Of course a good blueprinting never hurts, no matter the setup. If you are pushing the envelope with a schmedium to full-on solid roller, then yes, the race T&D are the best choice. I only did what I did because we have gotten by with the bushed Harland Sharps in the past with over 700lbs and nothing crazy for the stands like the race T&D. This was also on a drag only setup and the rockers were removed for winter to save fatigue. I was actually going to run the HS rockers with a good blueprinting, but during cam degreeing I noticed valve to wall clearance was a bit tighter than I felt comfortable with. So, I mocked up the Erson's and rechecked. They killed a little lift as I expected. I may have been fine with the HS rockers once I put the "real" valvesprings on and got a bit of deflection, but I felt the slightly less lift would benefit more with valve unshrouding. I also didn't feel like spending another 1500 or so for the T&D setup with milling included, when I already had a few sets of rockers laying around. I have about half invested in this setup right now compared to the T&D.
My apologies Brent, I should have never posted and caused this mess. I'll step out now. Good luck on the build.
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Would a setup similar to nightmist's but with removable tops with the base having a half round and a cap with a half round for retaining the shafts have an advantage here?Have the caps use straddle bolts or studs similar to OHC cam towers and use capscrews to retain the bases to the head allowing the elimination of the hold down stud and attendant hole in the shaft,it would allow you to use larger capscrews to retain the bases withiout fear of weakening the shaft due to a larger hole.It would increase the complexity of the assembly procedure but not terribly so.It would probably necessitate making the stands wider across the shaft to accommodate straddle bolt/studs but there appears to be room for that,you could even make the base so that the straddle bolts could inserted from the bottom of the stand so that your not depending on aluminum theads to hold them.Has this been tried before?
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Sorry, I just don't get all the discussion and debate here. If someone is using enough spring pressure to have the stands start moving around, you're much better off with the race T&D system. If the engine is built to that level, why risk stuff with a cheaper system? The valvetrain is NOT where you want to save money at! You've obviously spent some serious money on the engine already (not directed at you, Brent), so bite the bullet and do it right. It just doesn't make sense to do it otherwise.
I think we are all splitting hairs here. I mean that in a nice way and no disrespect to anyone. It has been an informative discussion so far. I feel for 80-90% of the setups out there with a flat tappet(solid or hyd.), hydraulic roller, or even a real mild solid roller that most of the rocker setups out there will handle the job just fine as is. Except for that cheap China stuff. That junk is just junk, lol. Of course a good blueprinting never hurts, no matter the setup. If you are pushing the envelope with a schmedium to full-on solid roller, then yes, the race T&D are the best choice. I only did what I did because we have gotten by with the bushed Harland Sharps in the past with over 700lbs and nothing crazy for the stands like the race T&D. This was also on a drag only setup and the rockers were removed for winter to save fatigue. I was actually going to run the HS rockers with a good blueprinting, but during cam degreeing I noticed valve to wall clearance was a bit tighter than I felt comfortable with. So, I mocked up the Erson's and rechecked. They killed a little lift as I expected. I may have been fine with the HS rockers once I put the "real" valvesprings on and got a bit of deflection, but I felt the slightly less lift would benefit more with valve unshrouding. I also didn't feel like spending another 1500 or so for the T&D setup with milling included, when I already had a few sets of rockers laying around. I have about half invested in this setup right now compared to the T&D.
My apologies Brent, I should have never posted and caused this mess. I'll step out now. Good luck on the build.
No skin off my nose....
FWIW, just as a builder tip, it's always best to check piston/valve or piston/cylinder clearance with the actual springs that you're going to use. Almost guaranteed that you will gain at least .020-.030" in your favor, if not more. I gave Jay this tip when he was mocking up his new cylinder heads and rockers and I think he gained like .070" or something crazy with his higher valve spring pressures.
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I have about half invested in this setup right now compared to the T&D.
My apologies Brent, I should have never posted and caused this mess. I'll step out now. Good luck on the build.
Jared, I was only speaking about the average builder, who isn't going to mess around with custom made stuff. Your set-up certainly isn't 'standard affair' parts. I also think it was a good discussion, with interesting ideas put to the test. It does show that some ingenuity can improve on the 4 bolt system, so I think your posts were a good addition. At least moderately...lol
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Sorry, I just don't get all the discussion and debate here. If someone is using enough spring pressure to have the stands start moving around, you're much better off with the race T&D system. If the engine is built to that level, why risk stuff with a cheaper system? The valvetrain is NOT where you want to save money at! You've obviously spent some serious money on the engine already (not directed at you, Brent), so bite the bullet and do it right. It just doesn't make sense to do it otherwise.
I think we are all splitting hairs here. I mean that in a nice way and no disrespect to anyone. It has been an informative discussion so far. I feel for 80-90% of the setups out there with a flat tappet(solid or hyd.), hydraulic roller, or even a real mild solid roller that most of the rocker setups out there will handle the job just fine as is. Except for that cheap China stuff. That junk is just junk, lol. Of course a good blueprinting never hurts, no matter the setup. If you are pushing the envelope with a schmedium to full-on solid roller, then yes, the race T&D are the best choice. I only did what I did because we have gotten by with the bushed Harland Sharps in the past with over 700lbs and nothing crazy for the stands like the race T&D. This was also on a drag only setup and the rockers were removed for winter to save fatigue. I was actually going to run the HS rockers with a good blueprinting, but during cam degreeing I noticed valve to wall clearance was a bit tighter than I felt comfortable with. So, I mocked up the Erson's and rechecked. They killed a little lift as I expected. I may have been fine with the HS rockers once I put the "real" valvesprings on and got a bit of deflection, but I felt the slightly less lift would benefit more with valve unshrouding. I also didn't feel like spending another 1500 or so for the T&D setup with milling included, when I already had a few sets of rockers laying around. I have about half invested in this setup right now compared to the T&D.
My apologies Brent, I should have never posted and caused this mess. I'll step out now. Good luck on the build.
No skin off my nose....
FWIW, just as a builder tip, it's always best to check piston/valve or piston/cylinder clearance with the actual springs that you're going to use. Almost guaranteed that you will gain at least .020-.030" in your favor, if not more. I gave Jay this tip when he was mocking up his new cylinder heads and rockers and I think he gained like .070" or something crazy with his higher valve spring pressures.
+1 and use CORRECT lash not zero and add the lash number. Using correct lash "picks up" the lobe far later which gives the correct piston to valve and IS about .015 or more .
Randy
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FWIW, just as a builder tip, it's always best to check piston/valve or piston/cylinder clearance with the actual springs that you're going to use. Almost guaranteed that you will gain at least .020-.030" in your favor, if not more. I gave Jay this tip when he was mocking up his new cylinder heads and rockers and I think he gained like .070" or something crazy with his higher valve spring pressures.
+1 and use CORRECT lash not zero and add the lash number. Using correct lash "picks up" the lobe far later which gives the correct piston to valve and IS about .015 or more .
Randy
Appreciate the tips, guys. I didn't mention, but I was checking with lash. I also ended up putting the actual springs on and rechecking everything again. As Brent mentioned I did see somewhere between .020-.030" less lift(and more valve clearance) due to deflection as I expected. I believe it was close to .030". Things tend to get tight in a 390 bore at over .700" with decent sized valves. I still felt like killing more lift with the Erson's would be better due to unshrouding the valve more. And yes, I also relieved the block to help unshroud the valves...
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Just following up on this.
Pulled the intake off JJ last night in order to get ready for an upcoming swap and checked the rocker stands when they came off. The stands did not show any signs of movement at all. We were pulling this engine to 7400-7500 rpm each time and with 680 lbs of open spring pressure, I think any fretting would have shown up.
I'm going to implement this modification on future builds where options are few, such as on Tunnel Port heads.