65Z01

The original engine, after close to 200k miles, finally locked up and I'm having it rebuilt to stock form.

At this point I'm having the stock crank "reworked" as necessary and going with new pistons & rods and heads work.

It has ProMagnum RR with hardened PRs and OEM lifters & stock cam.

My question is: will the original lifters likely be fine for say another 100k miles or do I need to spend the additional $$ to replace them??

BTW, the only "trashing" she will receive is some passes down the 1/4 mile in the Corvette Challenge.

BogusSVO

how wer they before the rebuild? if they were acting fine, then you should be ok. but since the heads are being rebuilt, if new springs or shims are installed under the spring, the increased spring loads may start the lifters to fail...

so its a crap shoot.... so let your wallet be your guide.. if you can afford new ones get them... if it cant install the old ones, but understand that you may be pulling the intake to swap them out.

65Z01

Before the A4 failed and then the motor, she made good power, though down a bit from say 4yrs ago.
About 6-7 yrs ago I installed ProMagnum 1.6:1 RRs, Comp Cams springs, Ti retainers with 10deg locks (stock cam) to reduce the stress on the valve train, which was still quiet before the "mishap".

The current builder is saying the old lifters should be fine.

I guess, since he is just doing a stock rebuild I'll let the lifters stay unless he sees a problem with them.

Thanks for the feedback.

BogusSVO

thats a bit of over kill on the valvetrain for that cam..... see if you can get your hands on a stock LT1 cam.. it will slide in with out issues and is not much more than what you have right now. I want to say its a .420/.450 lift but pulls good in the older roller engines

65Z01

Hmmmm....

warriorp

its worth the extra $175 to replace the lifters to know that i shouldnt have to take my fresh engine back apart...jmo

Chuck
ASE Master Engine Machinist

65Z01

Well the lifters is now a moot point as a cam lobe shows enough wear to warrent replacement, so the lifters will be done too.

Though I need a CARB compliant cam, I'd like to go with max lift permitted with untouched heads & stock valve recess pistons.

I'm looking at Comp Cams 08-300-8, max lift with 1.6:1 RRs at the exh valve is .512".

Anyone here know if the stock style setup will allow .520" lift at the exh valve??

Thanks for the advice on this build.

BogusSVO

no.... about .450 max on the stock springs... .500 if you run the Z28 drop in springs... comp should have a "drop in" spring and retainerset that should suite your needs and max lift is about .550

warriorp

Comp 983-16 or 941-16 should do the job for your application for a drop in spring...if you use the 941-16 you may have to have the guide boss cut to accomidate the inner damper spring

65Z01

Thanks for the leads on the springs; I'll try to stick with single spring with damper so there won't be a need for the boss work.

Anyone know the max lift before the exh valve would hit the stock style piston??

warriorp

on some heads the damper in the single spring contacts the guide boss...lots of variables come in to play on valve to piston .525 lift range should be pretty safe

65Z01

I had been checking "running length" of the springs to avoid coil bind or similar issues.

Good deal on that .525" safe value, thanks.