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Discussion Starter #1
I got a set of cometic head gaskets through my local machine shop. the reason is they offer a .025 thick for alittle more compression. They have three layers, the two outer layers are some kind of composite material (they feel like metal to me) they are perforated around all the coolant passages, like a factory steel shim gasket and the middle layer is just a steel shim. the machine shop said just to clean everything good and install them, not to put any spray or sealer on them. I am kind of leary about doing this I don't want to have leaks, and they were alittle pricey. If anyone else is using these I would like your input on how good they are and some installation tips.

thanks, mike
 

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I have a buddy that is using them on his N/A engine. He is running around 15to1 compression and never had a problem out of them. The guy that built my motor really likes the gaskets he uses them on everything. I would have used them on my motor but I already had the block and heads set up for copper gaskets. I think they are a really good gaskets and i don't think you would go wrong with them. My engine builder sparys a light coat of copper coat on the gasket just to make sure they seal. He said they told him not too but he was also alittle worried about them leaking. He as never had any problems with them leaking. So just to be on the safe side I would spary them with a light coat of copper coat.
 

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Discussion Starter #3
My next question is: I am currently at 9.22-1 compression with a .039 head gasket, and will jump to 9.57-1 with the .025 head gasket. My question is will it be worth the trouble to gain .35 compression? will I feel a difference?

thanks, Mike
 

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depends on assembly, if the pistons are down the hole and the .039 compressed head gaskets were causing you to exceed .045 quench, you might really be surprised with your gain. Lower octain gas requirement, more initial timming without detonation, resulting in more performance and less cost.
 

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Discussion Starter #5
I installed cheap flattop pistons and the deck to piston clearance is .033, yes I know it is alot. with the .039 gasket added it ends up to be .072 quench. with the .025 gasket it will lower it to .058. still not the optimal .045 but it should help. Could this be the problem why my engine seems alittle sluggish? Oh, I forgot to mention I had .040 off of the heads.

thanks, mike
 

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I used Cometic head gasget on my quad (LT250R, Quadracer) 8 years ago. It was also constructed the same way and was graphite lined. My quad is puting out around 17:1 compression, turns 14K RPM, firing every other revolution (2-stroke) and to this day has never failed. I didn't put a thing on the gasket or heads.....never even a seep.

Yes different from a v-8, but definitely satisfied with the gasket!
 

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Screamin' 90LX said:
My quad is puting out around 17:1 compression, turns 14K RPM, firing every other revolution (2-stroke) and to this day has never failed.
Doesn't a two stroke fire every revolution? :confused: It doesn't have a compression stroke and an exhaust stroke.
 

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SSSTANG said:
Doesn't a two stroke fire every revolution? :confused: It doesn't have a compression stroke and an exhaust stroke.
Yep. One down stroke, then up stroke of the piston, then BLAM. Hence, "two-stroke".
 

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What ever you do, don't put anything on the gasket, just clean the block good and the heads and bolt them down, before you bolt them down, make shure that the brass rivet is not in the way of the head, if it is, take off the brass rivet with a pair of needle nose pliers. My don't leak at all, I love these head gaskets, very good product.


Edgar

Sent me an e-mail address and I'll send you pictures.
 

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What are you guys torquing the head studs to and what lube on the threads for the cometics. Im about to try some I have the 7/16 arp studs.
 

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cometics

i am using cometics in a blwn applicaton (22-25psi) with no problems at all. u do know that the head and block surface must be prep. with a smoother than normal finish for proper seal? i also used a bottle of bars leak like the factors does during initial start up.
 
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