MelloYellow

Ugh...

Many people have problems with Cometic Gaskets?
I actually blew my NA MLS Gasket 2 months back (1 year old, 8k miles), which kicked off finishing my Vortech project and MTI install.

We had a new HP Series, but threw it out when we heard the problems and went with the original Cometic MLS style to be safe. Now we're having problems sealing up the Cometic even with studs. Going to have to remove the blower and take it apart.

Will dump the Cometics and switch to a GM MLS. Also going to swap heads for the new AFR 205cc's just to eliminate any other possible causes for our coolant pressurization. We needed to replace the valve seals on our installed heads anyhow.

Anyone else have Cometic nightmares?

amacgt

iTrader: (1)

i have cometics and run 15 psi and 150 shot of nos and no problems. I did put a little silicone around each water port on the block and the heads.

parish8

iTrader: (6)

i had coolant pressurization problems too. from what i understand you need a perfect surface for them to work well. i even tried the old coolant sealant tabs, what a mess that was. now i have the stock mls gaskets. i am running 13+psi and a 75shot.

i also over torqed the head studs by 15 ft/lb's. after asking around it seems many people do that. i didn't do that with the cometics so maybe that would have helped.

amacgt

iTrader: (1)

yea thats true, i had my block decked and heads milled so it was pretty flat.

MelloYellow

Thanks for the feedback.

My bore was 3.905 and Cometic recc'd 3.910 gaskets.
Head bore was supposed to be 3.905 but ended up 3.907.
A little tight on the clearance.

Also not sure if the cnc head bore matched the cylinder location perfectly. Either way, didn't work out for me. I should have gone +.020 on the gaskets.

Does anyone know the Stock GM MLS gasket bore size?

smokinHawk

iTrader: (48)

i had a problem not getting the 4.0" bore with my 6 liter heads with my 3.905

MelloYellow

I tried going with re-welded LQ9's with re-shaped chambers at 3.905", but they came out at 3.907" and am not sure how well they aligned with the gaskets. Either way our setup didn't work either.