Intercooler2

iTrader: (24)

Well a second spike to 260 today shows the Cometics are leaking into the coolant system. I'm going to notch the pistons while it is apart for extra clearance with the RapTr cam. How much is a good/safe notch depth?


Also what is the bar none best (and safest install) sealing head gasket for stock bore LS1? I'm not even against composite if they are the best. I knew going in based off my Buick experiences with Cometics it is rolling the dice. I lost and not looking to pull the heads again for a good period of time now.

SOMbitch

iTrader: (8)

GM MLS are very forgiving and easy on the wallet too.....

Intercooler2

iTrader: (24)

Who has the best deal on those? Any other great options? Also looking to put new header gaskets (GM) while there. Who has the deals?

vettenuts

iTrader: (4)

GM on the header gaskets as well.

Damian

iTrader: (89)

I've had so many issues with leaks on the Cometics over the years that I've quick using them entirely.

GM MLS is where it's at..

LS1-450

iTrader: (33)

I assume that the spike you describe is coolant temp? Why is it getting so high? If coolant is 260, then oil must be getting over 300. Neither is very good to your rings. Anyway, have you tried copper spray on the cometics? I use it &, knock on wood, haven't had leaks. Although, I monitor both coolant & oil temps closely & have an oil cooler.

Intercooler2

iTrader: (24)

It's not real. Hot gas squirts into the coolant system showing high temps for 2 seconds. It's happened twice I just pull over, let sit for a second and restart. Goes right back so they aren't real of what the engine is seeing.

Intercooler2

iTrader: (24)

No doubt. I should have learned from Buicks but figured I would try. With the GM's you think I am safe and it will go back to normal? Would like to hear your stories.

chrs1313

iTrader: (24)

glad my cometics .040s are holding up...i had my heads milled too so that might help with a fresh flat surface...

as for flycutting i have seen up to .120 cuts and a 150 shot....most recommend around .080...i personally cut mine .110...

let me know if you want to try out the lindy tool, i have rented it out in the past...

Intercooler2

iTrader: (24)

Yea we used Copper spray on both sides. ARP bolts were used and the heads were new out of the box. Will be interesting to see where exactly the leakage is. One side worked... other side didn't. Actually both did for a while but then this side showed it's ugly head.

chrs1313

iTrader: (24)

I didn't use any spray on mine actaully says right on the cometic package not to use any...

tillery

iTrader: (4)

I treated mine like a carbon seal and cleaned both surfaces. No spray on gaskets and using head studs.

LS1-450

iTrader: (33)

Ah, OK, I understand.
They should not leak since you used copper spray. Did you re-torque the bolts after a couple hundred miles? Maybe there was a kink in a gasket or a ding in the block surface?


BTW, I've looked @ the seal that spray provides when pulling my heads. It heats up & flows into even the smallest defect. So, when using enough copper spray, it should seal. Maybe a litter thicker spray coating can be used on your re-install; just a thought.

Intercooler2

iTrader: (24)

Burned too many times by them. Didn't see anything and coated 2x both sides. I'm going to just use the GM's... guess dry on those?

LS1-450

iTrader: (33)

GM's are fine. Was just talking about what you have now. You don't have to spray the GM gaskets. They have a coating that flakes onto the heads & block, but, I would anyway. Guess I've got a copper habit.

JFM-jr

iTrader: (23)

I used GM MLS gaskets on my LS2 no copper spray and they are fine. I'd think about having 2 thousandths milled off the head to provide a fresh flat surface for the gaskets. As for the flycutting the stock piston crown is around 220 thousandths thick. I have flycut .080 on my LS1 and currently have .060 on my LS2 (intake side only) both motors never saw nitrous and were spun to 7200.

abi

These can be had in 0.040' thick compared to GM 0.052' so tighter squish for power/compression gains.

on2

iTrader: (4)

Can't beat price and reliability of GM MLS head gasket. I just ordered a set today, $50 bucks.

260B4U

iTrader: (4)

where did you get yours ? my local dealer just quoted me 40 each

blsnelling

iTrader: (4)

I'm glad to find this thread, as I'm preparing to assemble my LQ4 with 243 heads. I'm not the least interested in anything other than 100% reliablilty. As abi asked, are there an .040 gaskets with a proven reputation?