LQ9 LS1 Major problems

[killer69]

WEll I need some help..... we have a 2001 GMC with a 6.0 in it that has now blown the head gaskets 4 Times ( I'm starting to think it's me )
the last time we used Diamond forged pistons eagle rods ARP studs Kometic Gastets resurfaced everything. tthe motor has a comp cam roller everything and a procharger making 6 PSI LS1 edit . bigger injectors dyno tuned makes 420ftlb at the tires with 35" mud tires on it and 380 Hp so it makes good power.
The driver is nuts!!! but still the motor should last more than 5 days. Has ANYONE run into these head gasket issues?? and what the Heck needs to be done to keep the thing together. i have seen many articles about these motors making big power but what gives.

[gen3bu]

did you have the block honed with torque plates with the studs installed?
what is the compression ratio?
is it always the same cylinder?
do you have a postable picof the gaskets?

[killer69]

Hum I am not sure if it was torque plate honed........ i dont think so. i have not seen what cyl it is THIS time but the last 3 times it has been more that one and on the outside of the head and also on the inside between the coolant pasage and the cyl. the compression is at 9:1 and it only makes 6psi of boost and is intercooled, larger injectors bla bla bla. i really have on other ideas as to what can possibly be done to make this thing last more than a week i mean Kometic (SP) gaskets are supposed to be the answer.......... but i guess not, i have no idea what to do

[gen3bu]

have you tested all of the injectors for flow/volume output?

try the gm mls 6.0 head gaskets. i havea couple of freinds running themon a 1530 fwhp 408 iron block race car. they hold 35+ psi.

[killer69]

Every thing seems good on the dyno? all at A/F ratios are good no real hot cyls. we put in brand new GM injectors from the 8.1 i would have figured the Kometic gaskets would have fixed the problem.

[Wildron]

the gm mls gaskets a the ****.work great and there is no scraping when you change heads/they are a 3 peice metal gasket

[Nutsy]

This may be a really stupid question, but did you guys retorque the heads after one heat cycle?

According to ARP (http://www.arp-bolts.com/Catalog/Cat...P2005_0036.pdf )

"Because the head gasket will compress upon initial torquing, make sure studs are re-torqued after the engine has been run."

[myclone]

If the engine wasnt bored/honed with torque plates then I highly doubt the head and deck surfaces were prepped for the cometics. The cometics require an almost smooth surface on the heads/deck compared to the rougher finish that regular head gaskets required. Cometics also require a REALLY flat head surface as well as deck surface.....no slop, for lack of a better term, allowed here like you can get away with when using felpro's.

The ppl with GNs and syclone/typhoons have had mixed results with the cometics from what Ive seen since some have held up fine while others leaked coolant as soon as the engine was started. It could be the surface finish or flatness or even a back yard hack style rebuild on the failed gaskets but none the less Im not ready to jump on the cometic band wagon just yet.

BTW, syclones/typhoons have 5 bolts per cyl like the SBC so the lack of clamping force prolly wasnt an issue on the leaking gaskets and the GN 3.8 only has four bolts/cyl and they seem to have about the same luck with the cometics as we do.....some worked fine while others poured out coolant instantly.

My .02 FWIW.

[killer69]

Other that torque plate honing the surfaces were both re machined and the engine assembled by a professional Pro mod racer so i think he knows how to assemble the motor and 54has used the cometic gaskets in the past.......... i am just looking for others experiances with these motors. as this is the 4th time the gaskets have blown and there are no real signs of wrong assembly procedures and all the good parts have been used talked to ARP prior to the 3rd time and they never said anything about retorquing and i have not asked cometic about it yet.

[Nutsy]

Blake, you may want to post on LS1Tech.com, LS2.com, & LS1.com.

We had an experience with a customers turbo car blowing headgaskets. After doing the retorquing thing resolved our issues, it wasn't a LS1 though.

[ReggD79406]

Also, Make sure you are following the torquing procedure for Gen3 motors. However, the surfaces & the cosmetic gaskets maybe the real issue.. Good luck!

Regi

[killer69]

I will try anything at this point thanks for the info