Head Gaskets - Input Please

[excobraguy]

Please look at these pics and tell me what you think. I had the head gasket blow and it was leaking water out the exhaust and steaming it away. It was also making a ticking sound.....it doesn't look too bad to me, what do you think? This is the passenger side head gasket, I have't taken off the driver's side yet. It was also a stock GM head gasket........

 

[excobraguy]

Anyone????????

 

[Turbo1dr]

Yup...there bad. Caused by extreme cylinder pressures from a lot of boost or detonation or popping.

 

[excobraguy]

Yup...there bad. Caused by extreme cylinder pressures from a lot of boost or detonation or popping.

Hey, thanks for the reply, the only one I got.........anyone have any suggestions on things to check, to do while I have the heads off?

Oh yeah, this might be a really dumb question, but I'll ask it anyway. The block is bored .040 over stock, does this make a difference when you buy new gaskets as far as a size or anything????? I'm assuming everyone will suggest the Felpro 9441PT's???????

Thanks guys.......

dean

 

[Turbo1dr]

Check for head and block flatness. Install intake and exhaust valve stem seals.

Stock headgasket will work fine with overbore.


I'll bet 90% of the Turbo Regals out there has head gaskets that look just like yours....bleeding cylinder pressure into the crankcase...and they don't even know it......YET!

 

[excobraguy]

Check for head and block flatness. Install intake and exhaust valve stem seals.

Stock headgasket will work fine with overbore.


I'll bet 90% of the Turbo Regals out there has head gaskets that look just like yours....bleeding cylinder pressure into the crankcase...and they don't even know it......YET!

I guess I was lucky enough to have mine make a constant ticking noise like an exhaust leak. I felt it leaking down at the bottom of the head right under the header. I kept test driving it with my Powerlogger hooked up...finally after a few nights of driving I finally started losing coolant and noticed some out the tailpipe.......I've heard good and bad about Cometic gaskets, what do you think of those? Man this is a job and I don't want to have to do it again soon, this engine only has 4000 miles on it. I'm running 18 lbs right now and have an alky kit ready to put in after I get the heads back on it. I don't want to have to do this again anytime soon! So as for the Cometic gaskets, any input?????

 

[turbofabricator]

I would suggest a set of Cometics. The .040" over bore might be compromising the fire ring placement. I'll have to check a block that is .040" tomarrow. I remember hearing about .040" not being able to seal up with stock gaskets. But I have never tried it. I'll look tomarrow. Anyone else run stock H/G with .040" over bore??

 

[bison]

RJC's gaskets work well and wont burn out like the graphite ones. Be sure to follow the instructions with them if you use them. If your car is not going over 120mph then the stock gaskets should last indefinitely if there is no detonation.

 

[excobraguy]

I would suggest a set of Cometics. The .040" over bore might be compromising the fire ring placement. I'll have to check a block that is .040" tomarrow. I remember hearing about .040" not being able to seal up with stock gaskets. But I have never tried it. I'll look tomarrow. Anyone else run stock H/G with .040" over bore??

I was wondering the same question and that's why i had asked about the size and the .040 over bore. Let me know what you find out, I'm not going to buy any parts until I get all my answers. Thanks for the help! Anyone else have input here on running stock head gaskets with a .040 over block??? Will it work?????

 

[excobraguy]

RJC's gaskets work well and wont burn out like the graphite ones. Be sure to follow the instructions with them if you use them. If your car is not going over 120mph then the stock gaskets should last indefinitely if there is no detonation.

I think after I add the Alky I will be. Right now @ 18 psi I have gone as fast as 113 mph in the 1/4.........

 

[bison]

I think after I add the Alky I will be. Right now @ 18 psi I have gone as fast as 113 mph in the 1/4.........

You must have had a lot of detonation then because the heads have been lifted many times for that much graphite to be missing. 18 psi is pushing it on 93 octane with no alky. Dont listen to anyone who tells you a couple degrees of KR is ok. It sure isnt if your running the stock gaskets hard. At 120mph a few degrees will do your gaskets in within a few runs. They will look like the set you posted pics of. Zero KR should be your goal. If the head surface and deck surface are flat you should be able to go 124-125mph on stock gaskets repeatedly if installation procedures were followed correctly. They will tolerate absolutely no detonation in the 125mph range though.

 

[excobraguy]

You must have had a lot of detonation then because the heads have been lifted many times for that much graphite to be missing. 18 psi is pushing it on 93 octane with no alky. Dont listen to anyone who tells you a couple degrees of KR is ok. It sure isnt if your running the stock gaskets hard. At 120mph a few degrees will do your gaskets in within a few runs. They will look like the set you posted pics of. Zero KR should be your goal. If the head surface and deck surface are flat you should be able to go 124-125mph on stock gaskets repeatedly if installation procedures were followed correctly. They will tolerate absolutely no detonation in the 125mph range though.

Thanks for the info. Did you see my earlier question on sizing of the new gaskets? The block is bored .040 over, what size gaskets will I need? I noticed on Cotton's website he has the following size chart for Cometic gaskets:

3.86 .40
3.86 .60
4.02 .40
4.02 .60
4.06 .40
4.06 .60
4.09 .40

What would I need?????

 

[bison]

Thanks for the info. Did you see my earlier question on sizing of the new gaskets? The block is bored .040 over, what size gaskets will I need? I noticed on Cotton's website he has the following size chart for Cometic gaskets:

3.86 .40
3.86 .60
4.02 .40
4.02 .60
4.06 .40
4.06 .60
4.09 .40

What would I need?????

I would avoid the stocker for the .040 overbore. Its a close call at .030. .040 may be too much. I myself would go for the 3.86in .040in thick gasket to bump the CR up a little especially if you are going to run alky. If no alky and no race fuel go with the .060. I would do at minimum three torques. I would torque them and let them sit overnight. Then back off and retorque again next day. Then once more after a few heat cycles and moderate boost. If you are using brand new fasteners you may want to do a few torques with those on old gaskets to polish the threads. Make sure the threads in the block are clean and use the non hardening thread sealant on the threads and the underside of the bolt head.

 

[excobraguy]

I would avoid the stocker for the .040 overbore. Its a close call at .030. .040 may be too much. I myself would go for the 3.86in .040in thick gasket to bump the CR up a little especially if you are going to run alky. If no alky and no race fuel go with the .060. I would do at minimum three torques. I would torque them and let them sit overnight. Then back off and retorque again next day. Then once more after a few heat cycles and moderate boost. If you are using brand new fasteners you may want to do a few torques with those on old gaskets to polish the threads. Make sure the threads in the block are clean and use the non hardening thread sealant on the threads and the underside of the bolt head.

What brand of non hardening sealant do you recommend?

 

[bison]

What brand of non hardening sealant do you recommend?

I use ARP's. Permatex has some too but i dont know the part #.