MY99TAWS6

iTrader: (3)

Who is running these. Did you do anything to your afr heads or block in terms of special surface preparation. Did you put them on dry or use copper spray or hylomar..not sure you can get hylomar in North America.
What boost levels are you running , what head bolts or studs? Any problems with the cometics. Either going to run these or ls7 mls gaskets. And need to decide right away.I am running cometic in my 97 talon and noticed no problems. Used copper spray even though cometic said dry in the instruction but confirmed spray was not going to hurt anything when talked to them directly about it. Pushed over 25 psi on that car with no problems.Arp heads studs in the 97 talon as well. A bit of head and block prep but nothing crazy.

And did you retorque the cometics and if so when?

nvmy2000ss

iTrader: (17)

I run them with no problems. I never retorqued them. I believe I went to 80 ft lbs.

MY99TAWS6

iTrader: (3)

How much difference in compression would I get from say .51 to .60 to .74 in the gasket thickness.Is stock gm gaskets .50? Last minute trying to decide between these and the ls7 mls ones. ls7 are cheaper. But don't want to cheap out at the expense of problems down the road.

helicoil

iTrader: (104)

Cometics, Felpro, GM MLS are all fine choices. Go with at least a 4-layer. No need to copper coat although it wouldn't hurt, just makes a un-necessary mess. If the block and heads have the right surface finish and the heads have been torque correctly it won't leak water.

Have your machinist shoot for less than a 30Ra on the heads and block, you can't be too smooth with MLS, but you can be too rough.

No need to re-torque if your fasteners have been run in at least 4-5 times. I don't think it really matters with a 4-bolt set-up, getting much beyond 18-20 lbs is not reliable if you are leaning on it.

And yes, hyloamr is available in the states, works good for those rocker bolts potruding into the intake runner on those AFRs

MY99TAWS6

iTrader: (3)

Well its too late to do anything with the RA on my engine. The afr heads are new and not cut or messed with stock from afr. The engine was built not exactly sure by who. Canadian performance sent it out to some shop in states need to find out more details. So would I be better off running gm mls gaskets or are they as fussy for RA as well? and why do I hear you can run some gm part number mabye for 6.0 heads but also guys are saying they run ls7 mls gaskets on the afr 225s. This whole thing is getting very confusing.

DeltaT

iTrader: (5)

I wouldn't go thicker than say .050" on the head gasket or you start messing up your quench. Piston or combustion chamber size change is the right way to lower your compression, unless there's something I'm missing about LSx engines.

I have Cometics for my new SBC/AFR/Whipple combo and am still debating the copper spray. Boost target is ~12(street), ~15(track) and am using ARP head studs. My AFR 227's came with a really smooth finish that easily exceeds Cometic's guidelines.

Yours sounds like a runner!

Jim

My Site: http://home.mindspring.com/~jim_fisk/id1.html

MY99TAWS6

iTrader: (3)

My compression ratio was supposed to be 9.5 to 1 and custom wiseco pistons were orderd to meet that goal . but can't ask my engine builder any questions to clear things up as he was Dave from Canadian Performance and passed away.
So am assuming he was going to use a standard type of gasket thickness which I would think is .50 or so? So figure then just get .50 cometics and call it a day.
I am going to be running alc injection anyway maybe e85 if we ever get it here.

As for being a runner well IT BETTER BE! Crossing my fingers.

HUNTER02SS

iTrader: (24)

I have the Cometics on my motor with AFR's. Work well, except I cannot keep from turning the boost **** up! LOL

eb02z06

iTrader: (18)

Bro, I'm running Cometic's .040 thick-wanted a tight quench since my compression is north of 10.1. I sprayed them copper sealant on both sides.
The GM LS7's are .054 thick and need no sealant.

Torque the heads down to 85-90 ft/lbs. I have no issue having them seal at 18 psi and 900 rwhp through a auto on pump gas and meth.

Big Bird WS6

iTrader: (9)

i have heard that for ever .01 in think is about .12 on compression on a 4 in bore.

now this is what my builder told me. so stock is .051. at 10 to 1. so you go to .041 you went to 10.12 to 1. and visverse for the other way.

hope this helps

MY99TAWS6

iTrader: (3)

ARUN do you have any idea what RA my block surface would be or what RA my stock AFR 225 heads are ? Is the RA on the heads and block good enogh as is for cometic or the ls7 mls? I think might put a light coat of copper spray on either gasket can't see it hurting .Cometic of course says not necessary but I did it on my 97 talon and it was holding like 25psi on it . Arp head studs as well.

I wonder what head gasket thickess Dave intended for my build up.He ordered custom wisecos to give 9.5 to 1 but not sure what thickness of gasket was presumed. If you can access any notes there let me know.

I wil likely be calling there today for sure on a few things.Do you stock the ported ls6 pumps and are they shimmed as well? What timing chains do you stock?

eb02z06

iTrader: (18)

Bro, the pistons are -15cc with a .280 thick deck. With the LS7 gasket at .054 you should be right around 9.45-9.5 with your AFR's@72cc's.

Dave figured the LS7 gasket with your build to get the compression you desired. It won't require any sealant either-just drop it on.

The block had a surface "cleanup" deck and can be used with Cometic if you desired.

I would use the Melling's 296 pump with the hi-pressure spring for sure. Your going to have alot of extra underhood heat with the turbo's and when the oil get's hot the oil pressure will drop.

MY99TAWS6

iTrader: (3)

Ok..thanks Arun that clears things up for me. The 296 don't fit well with double chains so for that reason think sending it back most likely for credit.
I don't want to have to mod or dremel the pump to get it to clear the double chain. Also while high pressure might be good for various reasons it might also cause oil out the turbos and require restrictors? And a bit worried about the high volume of the melling as well. With stock oil pan and pickup and all that won't it suck the pan dry even at planned 7000 rpm ? This oil pump stuff gets confusing!

MY99TAWS6

iTrader: (3)

Ok managed to locate some ls7 head gaskets off sponsor on the board..SPDC had them in stock .They were half the canadian stealership price and the canadian dealers had no clue as to when exactly they might show up but two to three weeks was thrown out. Not acceptable. Trying to get this finished.

As for pump went for slp pump and roller combo in stock and that was critical also as want it here yesterday.. and no grinding required and have choice of pressure think still going with lower pressure spring. I was just not into modding the melling or front cover to make things work. I am going to have enough grinding and modding when go to 4l80e most likely next spring! And the slp is just a melling think 296 that has been tweaked casewise to work with double roller no grinding required. Plug and play baby thats what I like! And no way would run single roller with my power goals. Want as much peace of mind as I can get!

Nice to know I can go with cometics also if the ls7 don't work out for me.
I am going to be staying likely 15psi or less, for sure under 18psi so doubt should have much problem with head gaskets.Have arp head studs and those afr 225 are thick deck heads. Be tuning conservative on timing as well. Think excessive timing is main reason guys go thru head gaskets. Greed is not a good thing when it comes to FI.

Thanks for the quick help Arun, Suzie sent me more data, a build sheet and stuff last night. Wish lived there so could bring it down and let you dyno and tune it. Oh well mabye get out there someday with it.