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

[Stangman]

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

[blykins]

I typically oil through the pushrods on my engines.

[Stangman]

Ya know I forgot that that’s one of your things.

[cjshaker]

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...

That's a really nice job, Jared. Every aspect of your engine is well thought out.

[gt350hr]

  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

[My427stang]

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. 


 

[plovett]

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

[My427stang]

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

[frnkeore]

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.

[blykins]

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. 

[frnkeore]

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.

[My427stang]

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.

[frnkeore]

Ross, what is causing this?

The majority of the vector of both is upward with sort of a rocking oscillation.

[My427stang]

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

[Nightmist66]

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.