Josh@KY-Turbo

iTrader: (120)

how many of you have bent the stock push rods in your cars? is this a common occurance? my friend missed a gear in his car and bounced it off the rev limiter (stock setting)and bent the **** out of 2 push rods. we ended up putting hardened cold rolled push rods in it. just figured i would ask. is there anything else i need to look for as far a stock parts breakage? thanks all

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Jason99T/A

iTrader: (21)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by wickedred:
<strong>my friend missed a gear in his car and bounced it off the rev limiter (stock setting)and bent the **** out of 2 push rods. we ended up putting hardened cold rolled push rods in it. just figured i would ask. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Next time your buddy misses a gear like that, he won't bend the pushrods. He will bent the valves instead. The problem is not the pushrods. The stock pushrods are actually fairly nice, especially for OEM parts. The problem is the weakass stock valvesprings. When you miss a gear like that, the motor over revs. Since the springs are not very adequate, you float the valves. This slams the valve into the piston. If you are using stock pushrods, these usually bend before anything major occurs. The pushrods act like "fuses" almost. Since your buddy is now running hardened pushrods, they will not bend. Instead, you will break/bend/destroy some valves and possibly a piston (depending on the extent of the damage). If you wish to run the hardened pushrods, swap the valvesprings out for some with more seat/open pressure. The comp 915s will work fine for the stock cam and some of the smaller LS1 grinds (up to a 216/220 or so). These valvesprings also allow you to reuse your stock retainers. Changing pushrods takes about 30 minutes and is very cheap. Bending valves and possibly damaging a piston requires major work and it will get quite expensive.

Good luck!

Jason

<small>[ March 30, 2002, 12:31 AM: Message edited by: Jason99T/A ]</small>

Bluestreak

This is an age old debate... leave the stock PR's in as "fuses"... or pull them out and use hardened ones.

I have a buddy who bent seven and broke one the first time... and bent five the second time he missed a shift, on a 100% stock motor. When we did his ARE S-II H/C package on his SS, his valves, surprisingly, were not bent at all - despite the fact that in the course of over-revving the motor twice he had kissed six of his eight pistons, all on the exhaust valves judging by the placement of the eyebrows.

So I consider that little experiment as pretty much proof-positive that the stock PR's can and do, in many cases, act as a "fuse" for the valvetrain.

But then there's also the fact that if the stock PR's deflect under heavy loading, they become springs themselves (until an over-rev, at which time you send them into their plastic zone, and they don't return to their original shape) - and incorrectly translate the cam profile to the valvetrain. That's obviously not a desirable trait in a significant piece of your valvetrain. I'd say... be careful, and make sure you're always cogniscent of how you're driving and shifting your car, and stay with the hardened PR's.

Josh@KY-Turbo

iTrader: (120)

thanks guys. he works at GM's Corvette plant so he is at no loss for money. i will pass on the advice to put in some better springs. this is his first stick car, so he will probably need the springs being missed shifts are gonna happen.

thanks again

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eboggs_jkvl

How can a motor over-rev by hitting the revlimiter? If you hit the revlimiter, doesn't the engine drop the RPMs immediately? IF you reset the revlimiter to a number higher than stock, then you can over rev the stock setup. Hitting the stock setting on a revlimiter should not bend pushrods. Hitting 1st when you are aiming for 3rd will or hitting 2nd when you are aiming for 4th will.

So, which is it? Did he hit the revlimiter or did he misshift and mechanically over rev the engine through the transmission?

Just curious.

ITT

Josh@KY-Turbo

iTrader: (120)

<img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> missed shift and mechaniclly over revved engine. went from 3rd at 5500rpm to 2nd and bang.
i have seen this happen with other cars and never seen this happen before <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" /> . that was until i posted here.

eboggs_jkvl

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by wickedred:
<strong> <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> missed shift and mechaniclly over revved engine. went from 3rd at 5500rpm to 2nd and bang.
i have seen this happen with other cars and never seen this happen before <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" /> . that was until i posted here.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">10-4! That'll do it.

ITT