Modifications on the 352's C6AE-R heads...

[gt350hr]

   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

[frnkeore]

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.

[blykins]

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.

[blykins]

   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. 

[Joe-JDC]

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

[frnkeore]

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.

[frnkeore]

Joe, how much of the hump do you leave?

[Joe-JDC]

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

[Nightmist66]

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.





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...

[Nightmist66]

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.

[GerryP]

... I figured at this point, it should be good enough.

..

That's a remarkable engineering exercise.

[blykins]

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.





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. 

[Nightmist66]

... I figured at this point, it should be good enough.

..

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.

[67xr7cat]

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!

[blykins]

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.   







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.