5/16" pushrods questions

[TurboTR]

Changing cams currently. With the manifold off it's evident that the exh pushrods are flexing around quite a bit, while the intake pushrods are not. Mine isn't the only one this happens on. It seems we're pretty much stuck with 5/16" dia pushrods with this heads combo. At full lift there's only about 0.008" static clrnc to the valve cover rail of the head. This with 1.65 rockers already too. We could hog that out some but the flex issue is what's bothersome. Current ones are the 0.080" wall I think. Question is, does anyone know of a thicker, stronger 5/16" pushrod? Or maybe a 3/8" to 5/16" tapered? TIA for any input.

TurboTR

 

[ijames]

What, no carbon fiber pushrods?

 

[TurboTR]

Hmmm...

TurboTR

 

[9SECVSIX]

Pushrods

Am using BBP 5/16"- that I purchased from Jim Butler Performance they are .116" wall and I think 9.130" oal, they worked fine with the Champion R heads, T&D roller rockers, FWIW I like and use lash caps. The pushrods were made by Smith Bros, I think they are located some where on the West Coast.

9secvsix.

 

[TurboCrazy]

Hi Todd,

What does the 224 cam look like after you got it out? Is it ok?
I'm still interested. Let me know when you get a chance.

Thanks, Brandon

 

[10SV6]

Re: Pushrods

Originally posted by 9SECVSIX
Am using BBP 5/16"- that I purchased from Jim Butler Performance they are .116" wall and I think 9.130" oal, they worked fine with the Champion R heads, T&D roller rockers, FWIW I like and use lash caps. The pushrods were made by Smith Bros, I think they are located some where on the West Coast.

9secvsix.

Smith Bros. is located up in Washington or Oregon. I got a card in the mail from them a few months ago that they've moved locations.

 

[TurboTR]

Sounds interesting on the .116 wall. There's also an 11/32" pushrod, and some tapered options too. Phone trail led to www.mantonpushrods.com yesterday. We're also checking out Smith Bros too. I think we can take care of this problem pretty much with some beefed up pushrods.

Never gave much thought to the forces exerted on the poor exh pushrod before this. Looking at the cyl press traces, there's still some 250-300 psi in the cyl when the exh valve opens. With a 1.65" valve we get over 500 lbs of holding force against the valve face. Plus a ~220 lb spring in this case, all amplified through a 1.65 reverse lever arm means the pushrod is pushing against some 1100+ lbs initially at EVO. No wonder it's flopping around...

Brandon the cam isn't out yet, still checking out pushrod clrncs with it all assembled. I suspect it'll look fine though. We'll know soon.

TurboTR