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

[Nightmist66]

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.

[My427stang]

I think it’s a good conversation, many ways to fix a problem

[frnkeore]

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.

[blykins]

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.

[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

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.

[cjshaker]

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 

[Heo]

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?

[67xr7cat]

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.

[blykins]

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.

[BigBlueIron]

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

[frnkeore]

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?

[blykins]

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. 

[My427stang]

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.

[gt350hr]

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.

[wowens]

Aw shucks, let's just weld them suckers.