355TurboLT1

iTrader: (11)

Trying to get a general feel of what is standard practice regarding cometic head gaskets and the addition of copper spray at time of install. This is for a buillt and boosted LT-1.

The heads and decks on the block have been prepped for the cometics but my engine builder used comp pro head studs! so I am going to have to remove the heads, install new ARP pro studs and maybe reuse the Cometics.

Lately I have heard if you dont use the copper they tend to push water, although a few LT-1 guys I know have never had this issue even with high boost. Thanks

J&J Speed Shop

iTrader: (8)

Cometic recommends you use NOTHING when you install their gaskets. They are already coated with a Fluroelastomer coating. I guess some people tend to use MOPAR sealant spray for their MLS gaskets.

Are you removing head studs to install new head studs? Why not just do 1 stud at a time and not even remove the heads?

355TurboLT1

iTrader: (11)

Yes I am replacing the cheap chinese head studs he put in with the ARPs. The only reason I would remove the heads while doing this is to coat them with sealant. I have heard that the cometics are coated as you confirmed and that they recommend against any additional coating, though many racers push water which might just be the result of a poor surface finish??

What seems to be the ticket as far as a sealant on the studs that enter the water jacket? I know ARP makes a thread sealant but I want to use what really works as I know studs like to leak at times.

J&J Speed Shop

iTrader: (8)

You can still coat the threads and do them 1 at a time. As long as you have room to remove the studs under the cowl area. ARP makes a thread sealer, but for a SBC/LTx block I usually use Permatex #3 Aviation sealant

elias_799

iTrader: (8)

i would not re use the headgaskets if the heads have already been torqued down on them

355TurboLT1

iTrader: (11)

Great news. I love it when i have to spend a few hundred dollars because of somone elses ignorance! So permatex #3 huh. I will check it out. Luckily the engine is out of the car. Has yet to be fired as it was just recently finished. For the life of me I can't see why he used the comp pro crap. I asked for ARP and he actually installed the arp main studs I gave him.

If I have to replace the cometics, oh well beats the **** out of pushing water when the motor is in the car. Thanks guys appreciate the advise!

Elite_Hot_Rod

As long as the gaskets weren't damaged during removal there is absolutely no reason not to reuse Cometics, I've done it several times without issue. When my set up was for N20 I used Yamabond on the gaskets, it's set up for a S/C now and we used copper spray on sealant when we replaced the crank just recently, no issues.

355TurboLT1

iTrader: (11)

So you used copper spray? I just spoke to a cometic tech who recommended against any sealant. But I realize there are other opinions based on real world trial and error so Im open to ideas. I dont want to push any water. That would **** me off even more than I already am looking at these chinese head studs!

Elite_Hot_Rod

Yes we used the copper spray this time around, no issues.

355TurboLT1

iTrader: (11)

Thanks. One more thing, what did you use for head stud sealant? Permatex. I have used there high performance thread sealer in the past and arp of course has a similar product.

elias_799

iTrader: (8)

no reason ? the gaskets are slightly compressed after you torque the heads down on them.

i understand that you have done it a million times and without a problem, but that is just not the proper way of doing it. plus i am almost certain that the head gasket that was torqued down once will live longer then the one that was torqued down twice.

355TurboLT1

iTrader: (11)

Well if I have to replace them then so be it. Just more fing money right! Need a recommendation on thread sealant for the ARP studs. What has been working well? Thanks

elias_799

iTrader: (8)

^^^ use the moly lube they supply with the head studs

please keep in mind that the torque numbers are different for arp moly against oil, just read the little paper that comes with the head studs and you should be ok.

355TurboLT1

iTrader: (11)

Copy. Thanks again!

Elite_Hot_Rod

Never said I've done it a million times just several times. Go ahead and replace those $150.00 a set head gaskets, we'll keep reusing them. Cometics are MLS gaskets, how far do you think they are going to crush? Do what you want I'm just saying that Cometics can and have been used more than once. We reused the cometics on my current F/I set up and it makes over 1000 RWHP.

Elite_Hot_Rod

ARP recommends using their assembly lube which is what we use, no sealant.

Firechikn

iTrader: (15)

I've used copper spray twice with no problems. I would do the one at a time trick.

elias_799

iTrader: (8)

ill replace 150 dollar head gaskets without thinking twice about it.

but i guess me and you have a different ways of doing things

355TurboLT1

iTrader: (11)

Well I have no issue buying new cometics. **** happens. If I cared about blowing money I wouldnt be building this kind of car right!lol. Still makes me angry though. I should have just assembled it like my last few motors. That way it would have been the way I wanted it the first go round. My main this is I have NEVER used cometics and want to be sure about the copper spray. They say no, but alot of you are saying yes to using it..... The last thing I need is a leak. I trust real world experience and appreciate all of your insight on this.