A friend of mine has an interesting theory on hardened pushrods. He feels that in the event an over rev he would rather have his stock pushrods bend rather than have a hardened pushrod cause a valve to kiss a piston. It makes sense, but then I think about how everyone upgrades their pushrods, so there is obviously something that I am missing.

Thoughts?

Inputs?


Brian

 

they will all cause a valve to hit the piston weather it is hardened or not. Once you add good springs to the mix if you have a valve hit the piston it is not going to be as easy as just change the pushrod. The valve will be bent anyways.

 

JRP where are you? LOL. try the search button on this topic.

 

This is true but the stock PR will bend easier and faster than a hardened one

 

I did not say it wouldn't. If you bend one IMO you also bent a valve once heads and cam are added.

 

I think the hardened push rods or to help avoid deflection from the stiffer springs and more aggressive cam lobes...

 

Yeah, that's what I thought too. The stock softies would deflect under am springs and especially with accelerated lifts on am cams. I got the hardened but I did not get the chromoly.

 

A situation pretty much like this had been brought up before. Tell you friend to keep his stock PR's after a good bit of power is added and he is revving higher. Something will eventually break.

I see where he is coming from though...

 

I could understand... stock rods are fine for a stock valvetrain. Get a cam and springs though and you should upgrade to some hardened chrome-moly rods.

 

Which ones are lighter? Ive been running the stock push rods. No problems so far but thats with the stock 6200rpm rev limiter. Im also curious whether the stock pushrods deflect and absorb some of the lift of the cam. Any deflection from the pushrods is multipled by the ratio of the rockers. It may be significant enough to cost some hp.

 

Funny I came across this. I actually spoke with Kip @ Futral about this subject. He said that if your going to upgrade the cam and springs, the you should also upgrade the PR's. He said that even the upgraded springs alone could bend the pushrods becasue of the rate on them. If you bend a PR, be almost cetain that that isnt your only problem. If that happend you surely did damage elsewhere. The stock ones are crap for anything other than just stock and even at that, they still suggest upgrading them. Im going to just for peace of mind if nothing else

 

Thanks for the input guys.

And sorry that I did not search