Why are stock head gaskets so special?

[TurboBuickSix]

My stock head gaskets are fine as far as I can tell.I have a set of ported irons I want to put on over the winter, and some folks told me not to disturb the stock head gasket seal that it would'nt be possible to get that good of a seal again.This sounds like an old wives tale to me and I would like someone to explain if they know the facts on this.
I also heard if the stockers blow they can put graphite into the motor and cause more harm,true or false?

Let me know what you think.

 

[zam70]

The belief is that the OEM head tightening procedure can not be replicated. I remember something about all the head bolts were torqued at the same time and rate (basically all at once)
This is why everyone says DON't break the factory seal...

Will the factory headgasket put crap in your engine/turbo. Yep.

Alot of people run the cometics or OEM steel shims and have mucho good luck.

 

[sumnerw]

I would clarify that old wives tale to state that factory installed stock head gaskets should not be disturbed for anything less than a compelling reason. Installing ported iron heads is probably a compelling reason but be prepared for sealing problems.

It is my understanding that GM tightens/torques all of the head bolts simultaneously and thereby achieves even clamping force across the entire head and gasket. This process cannot be replicated in my garage and I have had less than stellar results from sequentially torquing head bolts. The narrow part of the gasket between the cylinder and the intake manifold seems to let go first, probably because of head lifting (and poor tuning).

Good luck,
Buzz White in Houston, TX (sumnerw@flash.net)

 

[TurboBuickSix]

So I can dig in without fear?? Seems like a good idea to head off the damage anyhow.Only problem is that I don't have 15 freinds with torque wrenches to help me tighten these bolts though thanks ZAM

 

[TurboBuickSix]

Maybe copper o-rings would help? I really would like the advantage of these better flowing heads but this is a tough decision.It makes sense about the GM procedure being better.Thanks for clearing that up for me.

 

[U1ARUNIT]

As was already said, go with the Cometics or stacked steel shim type with the proper adhesive. If you choose the latter, Race Jace sells a kit with the shim gaskets, sealer and instructions. It's all good.

 

[mgmshar]

It is true that engine plants install cylinder heads by torquing all of the bolts simultaneously. And yes, it does make for a much better seal than torquing each bolt one-at-a-time.

How can you duplicate the factory procedure? By torquing the bolts in the correct sequence in VERY small steps. Like 10 ft-lbs. at a time. It's not exact, but it's as close as you will get with one torque wrench.

Unless you want to invite your 15 friends over...

 

[Hammer]

Actually how hard would it be to duplicate gm assy. procedure.? Somebody should be able to rig up a group of torque sensing pneumatic (impact)wrenches to fire all at once.If a shop had one it would be a popular tool.Just a thought from a tinkerer.

 

[Quick6'n'-K.C.]

DANG-
everyone must be thinking 15 bolts per side

its 8 per side, so you only need 8 snap on torque wrenches at 365.00 each, then beer for the buddies, plus dinner, head bolts,head gaskets.. man, your in for it

sorry for the sarcasm

the factory seal is the best like alot have said, i havent had any problems using GM headgaskets- since yours arent blown, your not going to put any graphite into the motor, well, till you blow them in the future-
BUT, now your not going to have to run as much boost because you have ported heads, and you will gain about 40 solid horses

torque em down to 60 ft lbs or a tad more if you need to using the procedure on gnttype.org
i use 66 ft lbs on them and 69 on the drivers back side lower with a short extension using my snatch-on adjustable torque wrench-

i would definitely do it-

BW

 

[Low Budget]

Head Bolts

I'm surprised nobody mentioned this yet! When you do this job, you will need to replace the head bolts. ARP would be the way to go of course. The factory bolts are I believe called torque to yield and are useable only once. Can't explain it well. I guess they're like torsion arms that are worn out after being twisted one time. If you try to reuse them, the heads will probably lift under pressure. Pop goes the gasket again.

 

[49-blues]

Quick6n-you only torque your headgaskets to 60-66 lbs, i thought 75-85 was more realistic?

 

[1badTTA]

50-60-70-80-85lb/ft

thats what I do mine to using Jasons steel shim kit with the goop. ARP head bolts "cycled" several times.

 

[87ttypeV8]

whoaaaa

are we talking 85 ft lbs on an iron head??

i just did my headgaskets and did everything by the book (gnttype) and i believe only torqued them to 65 ft lbs (gulp)

should i possibly break the bolts loose, and retorque them?

they are ARP and this would probably give the head an even surface or whatever... i remember reading to run the car and then break em loose and retoruqe i think....

 

[turbodave231]

The real reason to leave the factory gasket alone is because they become "glued" in place with time and tension. If you have ever removed a head with a factory gasket, the gasket literally comes apart in two....half on the head and half on the block...and it will take a pry bar to remove the head.

A replacement gasket will eventually glue itself in place too. I have only used GM gaskets, GM TTY bolts and the factory tightening procedure. Yes, I have lost a few gaskets, but at 29 PSI a degree or two of KR will do that.

Blowing a factory gasket will put some gasket material in the engine, but if you remove the oil pan and clean the valley area out with brake clean....no big deal.

It is more important to pay attention to your head and deck surfaces when replacing your head gaskets. Flat and rough is most desireable. Don't use the scotchbrite discs to clean the head or deck. Those discs polish the head surface and the new gasket won't bite into the metal.

I am sold on the factory parts and procedures.

Dave

 

[Quick6'n'-K.C.]

Originally posted by 49-blues
Quick6n-you only torque your headgaskets to 60-66 lbs, i thought 75-85 was more realistic?

yes that is what i torque em to, 60-66..

arp thread sealer and moly lube on the head and washer-

if you use a oil, then up the FT LBS i think 10 more...

i too did em on a few cars and no problems yet-

also-

NAPA sells a TTY head bolt kit with composite gaskets just like the GM gaskets-
in the distructions it says to clean out holes, and then start torquing in the correct pattern per directions... last line reads,...when 60 ft lbs has been reached then STOP torquing them and your done...

i hope im its all good- it says 60 on GNTTYPE.ORG ????

PS- those NAPA gaskets and TTY bolts lasted 8,000 miles and we pulled the heads off to put ported heads on 3 days ago- #4 fire ring was pushING out into the intake, and about 1/4 mile pass away from completely blowing out-
keep in mind a few passes were made and the guy ran out of alky getting 30° of knock retard and running 28 psi of boost
gaskets had at least 200 passes on them, and daily driven since i rebuilt the motor in the garage this early spring.

still cheaper to buy GM gaskets and ARP bolts thou, he just got a discount since he works there at NAPA...

BW

 

[d0n_3d]

factory head gaskets rule that's all i gotta say...my car was rarely driven from 1987 to 1997 (26k miles)...since 97 i have the odometer up to almost 100k...my car was bone stock up until 2001 and up until last summer it was very mild mods with stock everything...so i would guess that my headgaskets are VERY much unbustable unless an EXTREME condition came up like 40 degrees of knock or something...because the car basically never detonated and i have always let off when little knock showed...a few times i hit the redline on the knock gauge but it was like 10 degrees of knock retard and it was accidental...i have pushed the limits on this turbo at sometimes 27-28 lbs of boost and no knock...i can say that the headgaskets are holding up quite well if they can handle that much boost...never mess with a good thing...run the stock motor until it actually does bust a gasket...that's just my opinion

 

[WSLN 6]

Ya, it's almost going to be a shame to remove and port the heads because of the durable stock head gasket.
I'm spoiled running 30+psi on a daily basis....

 

[turbosam6]

The factory gakets can weaken with detonation, instead of just blowing all at once. Thats why you hear of guys blowing hg's on very little knock or low boost, its like the straw that broke the camels back, so to speak. Your factory gakets are not "unbustable", every time you detonate you hurt them a little. If you're gonna start really modding the car, I would not hesitate to break that factory seal and put on some good heads. You'll have your motor apart more often anyway when you start going fast, plus you'll likely stop driving the car as much.

The first time you get into it with those ported heads you'll never look back anyway!

 

[Quick6'n'-K.C.]

Originally posted by WSLN 6
Ya, it's almost going to be a shame to remove and port the heads because of the durable stock head gasket.
I'm spoiled running 30+psi on a daily basis....

Ya, its almost a shame running 30psi of boost daily on stock heads lifting them just a little bit more everytime you get into it

dont worry, running 30 psi of boost everyday, you will pop a head gasket soon enough, and wished you had a set of race ported heads waiting to bolt on when you do the head gaskets

i think its a good idea to have em ready cause you never know when a gasket is going to pop-
right now ive got 2 sets ready for my cars just cause i know its going to happen

 

[WSLN 6]

Oh come on now Bryan! Only one more track day left for the year, then it's in the garage for a good head porting/posi rebuild/downpipe install......
It should last one more track day right?
Ok, I'll bring a tow rope.