Cometics are leaking
Just curious if you retorqued the ARPs after they sat for an hour? I went back over mine (ARPs with Cometic (no copper)) and they took 1/2 turn more each to torque properly.
Sounds like you need to get the machinework straightened out. good luck
Sounds like you need to get the machinework straightened out. good luck
You didnt say what heads your using ,but if you ars using ls-1 heads with a mls gasket you will have a leak. There are notches in the castings by #s 3&6 cyls. that will leak coolant unless you have the notches welded up or just use the composite gasket.
Originally Posted by triumphman
... if you ars using ls-1 heads with a mls gasket you will have a leak. There are notches in the castings by #s 3&6 cyls. that will leak coolant unless you have the notches welded up or just use the composite gasket.
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I'm using AFR castings. They don't have the notches cut in them. I'm fixing to go fill the car up with coolant right now. I'll post up in a bit how it works out.
Cometic told me to use the 3.970 gaskets and not the 3.910 as they are too close to the cylinder wall, not a big enough bore. If you measure the OEM graphites they are 3.970.
I used cometics on a 6.0L block with 5.3L heads and h11 arp studs with no leaks for over a year with nitrous. I did use the copper spray on both sides and torqued to 80 lb/ft. I retorqued three times after letting them sit over night.
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Originally Posted by strokedls1
I used cometics on a 6.0L block with 5.3L heads and h11 arp studs with no leaks for over a year with nitrous. I did use the copper spray on both sides and torqued to 80 lb/ft. I retorqued three times after letting them sit over night.
Originally Posted by Beast96Z
I let it run for a while and let it sit for a few hours in a nice clean spot in the drive. I just pulled it in the garage and there were no leaks as of yet. 

Originally Posted by bigdsz
Cometic told me to use the 3.970 gaskets and not the 3.910 as they are too close to the cylinder wall, not a big enough bore. If you measure the OEM graphites they are 3.970.
Would using to big a gasket cause leaks also? I measured the ones that I took off my girlfriends car that were leaking and they measured 4.030.
Originally Posted by Spellbound
Would using to big a gasket cause leaks also? I measured the ones that I took off my girlfriends car that were leaking and they measured 4.030.
Originally Posted by Beast96Z
This is exactly how I went back with mine. I sprayed the gaskets, torqued to 25/55/and 80, then went back over them later after they had settled a bit. I used motor oil this time as the lubricant and not the ARP moly lube. Everything seems to be ok thus far. I let it run for a while and let it sit for a few hours in a nice clean spot in the drive. I just pulled it in the garage and there were no leaks as of yet. 

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Just to update, I threw the pressure tester back on it and pumped it up to 17lbs. There were no leaks to speak of and she passed the "pressure test" per the instructions of the tester. It looks like it's gunna hold. I'd reccomend anyone with these gaskets to spray a light coat of the copper sealant on them before installing. It won't hurt anything, and isn't worth the extra headache you might get if you don't.
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Originally Posted by Visceral
Can you describe this copper spray stuff please? What is it and where can I get it? (I have to install some Cometics in a couple weeks)
thanks for the hints,
Chris
thanks for the hints,
Chris
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Originally Posted by ArcticZ28
Permatex makes some and it's in a blue spray can with the dimensions of something like a can of brake cleaner. Any auto part store should carry it.





