Yes, because there is much more cylinder pressure trying to lift off the head on a road race at 22psi than the drag strip at 34psi.

If no one can find ONE simple case of a head lifting off an Evo with stock head bolts, then the thread should be locked.

This is a mildly modded Evo with 20 something pounds of boost on 93.

 

Forget the headstuds and get some JAM no tick lifters instead!

 

He needs lifters about as bad as he needs headstuds at 22psi.

 

Yeah untill his stockers start ticking after the cam swap.

 

If you bleed the lifters they won't tick.

 

The lifters do not need to be bled, nor do they tick due to cam swaps. 4g63T lifters have been ticking since 1989 as a 1990 model car. They will always be subject to ticking at various times and for various reasons. That does not mean anything is wrong with them.

I have personally installed 92 sets (184) Evo cams on all years and most every brand.

 

No...you don't NEED to...but it seems to help apparently no? My mechanic also says to bleed them because it's easy and takes hardly any extra time.

https://www.evolutionm.net/forums/sh...d.php?t=137999

 

Its a waste of time, the cam is out and replaced, recompressed within about 120 seconds during our install.

 

That's apples to oranges on boost. Where did you get 34psi from? Where did you get 22psi from? Anyways it's not even debatable. There's significantly more stress exerted on the head during a 45 minute run around a closed course than a 13 second pass down the 1320.

But you're right...like most other Evo owners, this will absolutely be his last mod ever and there's zero chance he'll never see 22psi+ and/or a closed course.

 

What does the timeframe have to do with the oil displacement in the lifters? It takes all of a couple seconds to bleed the lifter, by not doing so the installer risks applying too much pressure due to the increased lift of the new cam--which could lead to blowing out the lifter's seal.

Of course you can rev up to the 3k and let off a few times as well, but either way, it's a minescule effort and good preventitive maintenance. Regardless if it takes 2 minutes or 10 minutes.

 

34psi is what is capable on the stock turbo.

I did it for over a year on stock head bolts with no ill effects. Unlike many with unfounded opinions and NO FACTS to support claims that studs are necessary on pumpgas boost. The notion is ridiculous.

His car is a pumpgas car which will not ne running more than pumpgas boost.

There is MUCH LESS cylinder pressure at 22psi than drag boost/high octane or meth.

Its not debateable because 45 min, 5 hours, the bloody ROLEX 24 has ZERO impact on cylinder pressure. Cylinder pressure lifts the head and stretches bolts, not a time period of driving the car in a spirited fashion.

Even though I have tuned hundreds of Evos at over 30psi from stock turbo to IX to Evogreen's at 38-40psi, 30R, 35R and the like on studs, I have tuned just as many of the same on stock bolts and never experienced any HG issues, head lift or stock bolt stretching on any Evo.

The funny part is neither has anyone else in this thread, but since you read it on the internet somewhere that studs are needed, it must be true.

Unless you have your head off the car for a build or you are pushing over 550whp, studs are not necessary to protect your car from a MYTH that has been busted.

I ENCOURAGE ANY MEMBER OF THE 15,000+ EVO'S ON EVOLUTIONM.NET ALONE TO COME FORWARD WITH ONLY (1) ONE OCCURANCE OF HEAD LIFT OR HG FAILURE AS A RESULT OF USING STOCK BOLTS.

I suspect it will never happen, cause it is but a myth that many have fallen for.

 

The installer does not risk anything. The seals will not blow out on the lifters any faster than with unmolested cams.

It takes neither 2 minutes or 10 minutes. Maybe 25-35 min.

16 rocker need removal.

16 lifters need removal.

Lifters get bled if the installer can do it correctly. You have a better chance at damaging the lifter by jamming a piece of metal up into the lifter than just swapping out the cams themselves.

Time period is notable as if you leave the lifters uncompressed for 20-30 min before the new cam gets installed, hypothetically it may be harder to compress.

My suggestion is to pop out the old cam, have the new one ready with assembly lube and pull out and drop in the new, screw down the bearing caps in the correct torque order and you're done.

 

I see your point. The skill level of the installer plays a huge role.

 

well i dont know if it is a myth. i think that the stock bolts are fine for his situation. but its not a myth that the stock bolts are weaker than studs...its just a myth that he needs them for his situation. if someone can prove me wrong that the bolts are just as strong as the studs then i would like to hear it.
but TTP i am definately not saying he needs them or that his head will lift without them. im talking about the strength of the stud versus bolt

 

That is the point.

They are not needed at his modification level and WAYYYYYYYY beyond.

The arguement is not that the bolts are stronger than ARP stud and nut combo.

The arguement is that the upgrade is not needed.