Steel shim head gasket question...

[TurboBob]

Nick,

Do you retorque before the first startup or after the first cooldown?

ARP's or TTY's ?

Do you have shim gaskets in stock?

do you have any data (other than compression ratio) about the
relative longevity of stacked shims as opposed to singles.

Bob

 

[Nick Micale]

Originally posted by TurboBob
Nick,

Do you retorque before the first startup or after the first cooldown?

ARP's or TTY's ?

Do you have shim gaskets in stock?

do you have any data (other than compression ratio) about the
relative longevity of stacked shims as opposed to singles.

Bob

Re-torque after 24 hours usually on the engine stand. Again after a couple heat cycles. Maybe a third time if lots of strip use is involved.

We use ARP 190k bolts to 85ft-lbs, torque in 3 steps.

The GM part no. is: 25524599, ~$10 each

Using 2 shim gaskets per side gives about 0.034-.036 thickness. Stock gasket is 0.060. This will mean ~0.5 increase in compression ratio. Stacked or single should both hold the same.

We use Hi-Temp copper spray on both gaskets and install when tacky. Others use Hylamar spray or GE 1200 silicone rolled on the gaskets.

 

[buickboy]

let me explain the difference in technology. GM steels are stainless steel (no memory, no coatings). Cometic multylayer steels are stainless spring steel (memory) emossed, riveted together and Viton coated on both faying surfaces. If the head lifts with cometic, spring steel has memory and will move with the head. That is what Cometic claims. I do know that Brodix heads uses nothing but Cometic and also the high HP turbo V-8's around here use Cometic. BTW, i am glad i work on my own car so i don't have to pay 200 percent markup on parts cost, plus labor.
Mitch

 

[Intercooler]

Originally posted by buickboy
let me explain the difference in technology. GM steels are stainless steel (no memory, no coatings). Cometic multylayer steels are stainless spring steel (memory) emossed, riveted together and Viton coated on both faying surfaces. If the head lifts with cometic, spring steel has memory and will move with the head. That is what Cometic claims. I do know that Brodix heads uses nothing but Cometic and also the high HP turbo V-8's around here use Cometic. BTW, i am glad i work on my own car so i don't have to pay 200 percent markup on parts cost, plus labor.
Mitch

I thought the GM steels were carbon steel FWIW I did call Cometic. It seems they are used widely in NASCAR but he couldn't give me one big name period in drag racing using them. This is a market they are trying to break into and displace copper/o-ring setups. I couldn't find the prices you got. Best was $72.50 ea. for .040" 3.860" gaskets #C5691.

 

[Nick Micale]

Originally posted by buickboy
...... That is what Cometic claims. I do know that Brodix heads uses nothing but Cometic and also the high HP turbo V-8's around here use Cometic. Mitch

Well let's see, we have Cometic claims, Brodex heads and high HP V-8's?

Let me know how the Cometics do after 50-100 WOT runs at 26-29 psi on stock turbo Buick 8-bolt heads!

 

[Chyke]

Kind of seems like a pissing match

So..... I use SCE 0.62 coppers with copper wire orings in the block, out 0.10 in a figure 8 fashion. Totally coated with a can of spray hylomar, ARP studs tq to 85 ft/bts all around in three steps and rtqed after 24 hrs, not by loosening each fastener, but by raising the tq 2 pds to over come static pressure to assure 85. WORKS GREAT. Street driven many miles........

 

[TurboBob]

A friend just blew a FelPro 1026 (I hate those)
(car runs, it's just dripping coolant....)

He's going with a pair of steels, they should be the same thickness as the FP.
He's only doing the one side. (for now....)

While he's at the dealer he's going to get some gaskets for my head-swap
and extras for the other side of his motor.....

TurboBob

 

[TrboHead]

Cometic

Felpro 1026 are not the way to go with the GN1s. I blew mine out the side at 23 lbs of boost 22 degree timing with no knock right out of the gate. Torqued 85 upper 75 lower, retorqued, assembled correctly, yadda yadda. I possibly could have gone 85 ft/lbs on all but now we are getting into another subject. No reason for these to blow. I've tried Felpro wire loc also with better luck but still blew several of them. Once the head moves around under pressure these seem to give way by distorting the receiver groove on the alluminum head.
I will try the Cometic for the fact that the heads will lift and I need the gasket to move with it. Also I know of some high HP blown Fords that are getting little or no leak down after 30+ runs.
How much I'm saving on this gasket vs. that gasket is not part of my thinking at this point. You could actually reuse the stock steel shims(old school). Wow...what a savings, if I could only find that dried up tube of goop, look at all the money I'm saving.

 

[Intercooler]

Re: Cometic

Originally posted by TrboHead
Felpro 1026 are not the way to go with the GN1s. I blew mine out the side at 23 lbs of boost 22 degree timing with no knock right out of the gate. Torqued 85 upper 75 lower, retorqued, assembled correctly, yadda yadda. I possibly could have gone 85 ft/lbs on all but now we are getting into another subject. No reason for these to blow. I've tried Felpro wire loc also with better luck but still blew several of them. Once the head moves around under pressure these seem to give way by distorting the receiver groove on the alluminum head.
I will try the Cometic for the fact that the heads will lift and I need the gasket to move with it. Also I know of some high HP blown Fords that are getting little or no leak down after 30+ runs.
How much I'm saving on this gasket vs. that gasket is not part of my thinking at this point. You could actually reuse the stock steel shims(old school). Wow...what a savings, if I could only find that dried up tube of goop, look at all the money I'm saving.

Bottom line is..... if you are having such bad luck with all the head gaskets you are trying, something is wrong. Either your tune, your install, your components. In there lies the real problem.

 

[lazaris]

The 1026's are made to be run with 14 bolt pattern heads....

 

[TrboHead]

Yes. Problem is the nut behind the wheel. I thought I could safely run the Felpro 1026 with no knock, 22 degree, 840 mv, properly warmed up motor to 180 degrees and retorqued heads the prior day. I even used proper head studs, torqued in sequence with moly lube, loosened retorqued after 30 minutes then 1 hour, loosened retorqued the next day. I was wrong. These are made for stage 2 big bore. I knew that going in but decided to try them anyway.

Don't use the 1026's on stock block. Even the other head had signs of carbon blow out.

 

[toofastforyou]

UPDATE !!!! READ THIS!!!!

After having blown the stock head gaskets, I went with GM steel shim head gaskets, carefully coated with silicone, torqued the heads to 85lbs, using brand new ARP bolts. The next day, I re-torqued the heads to make sure everything was ok.
So on the next sunday, I went to the track to try the car out and believe or not, on the FISRT PASS, the f*****g head gaskets let go again!!! On the first pass! Only at 20 lbs of boost, with 0 knock on the scanmaster...I was only halfway down the track when it let go!!!
So I'm having the whole engine refreshened, the heads checked to see if they are warped or not, and also the block checked, and I'm going to go back to the stock GM gaskets. !!!
At least I learned that steel shims are not the way to go...I can't believe this...one run!...
Well, I guess that's part of the things you learn when racing...
'Bye, Claude.

 

[REDS HOT AIR]

can i ask why you say a gm steel blew??

they can leak by but it would be really hard to actually blow one.

my last set leaked by when i put them on with arp bolts at 85# and just for giggles i pulled the head bolts to 100# and they never blew by again

but i never replced them i just tightened it up more...personally i dont think they will hold alot of boost with bolts at 85# its not enough clamping force

studs at 85# have alot more clamping force due to having fine threads.

dont fall over when i tell ya my studs are torqed to 100# now...

i dont plan to have a head gasket leak... when something lets go its gonna be nasty cause the head gaskets are not gonna give and i girdled the block so it shouldnt give either

its in the car all hooked up to be fired nce i get up today and go get a belt to fit it with the a/c delete pulley and im scheduled a track pass friday night and if my 340 pump will keep up it will be getting some boost shoved up its.....t/b..

 

[Intercooler]

Re: UPDATE !!!! READ THIS!!!!

Originally posted by toofastforyou
After having blown the stock head gaskets, I went with GM steel shim head gaskets, carefully coated with silicone, torqued the heads to 85lbs, using brand new ARP bolts. The next day, I re-torqued the heads to make sure everything was ok.
So on the next sunday, I went to the track to try the car out and believe or not, on the FISRT PASS, the f*****g head gaskets let go again!!! On the first pass! Only at 20 lbs of boost, with 0 knock on the scanmaster...I was only halfway down the track when it let go!!!
So I'm having the whole engine refreshened, the heads checked to see if they are warped or not, and also the block checked, and I'm going to go back to the stock GM gaskets. !!!
At least I learned that steel shims are not the way to go...I can't believe this...one run!...
Well, I guess that's part of the things you learn when racing...
'Bye, Claude.

Curious about this myself. When you say blew...... as in a chunk was missing or blown out or just seeping? Did you stack them? If you "blew" one that quick a stocker will be even more likely to blow in the same situation. Something is wrong!

 

[TrboHead]

I can see that if you torqued the steel gaskets to 100 lbs instead of 85 that it would not distort the gasket as much because there is no fire ring to crush. Has anyone torqued their heads way beyond the suggested torque settings for other gaskets? Could you torque the steel ones to 120+? At some point you would distort the head.