Ketchmi

I have had problems with Cometic headgaskets and recieved the same response...pull them out and we will replace them. They say it like it's an easy thing to do! I have used a ceramic block sealant and the coolant leaks stopped but they continue to leak oil. There are now ways to make them seal before installation and you will find nothing tougher if you are boosted.

928SS

I've heard about that, think we may have considered it but it seemed to quit on it's own before we messed w/it... I think it's too late for a magic can of fix-it-shyt now though...

ps we don't want you to die before you tell us EVERYTHING

928SS

I remember you tellling us that course I didn't listen I think I even had the chance to swap them before I put them in, but they couldn't tell me for sure if my set was part of the "problem series", so I just rolled the dice cause I was impatient/felt lucky at the time... oops

GregBBRD

I gave up on Cometic gaskets six months ago. Rob's gaskets were the first that we had ever tried on the 928 engine (he brought them to me to install). They leaked like a sprinkler system when the engine was first started up. This decreased when the engine was run through a couple of heat cycles. We have used several other sets (over a period of a couple of years....so I assume we have gotten the latest and greatest gaskets from Cometic) and they all have leaked. We thought we might have solved the water leaks by using a sealing product in the water, but they all leak oil from the area of the oil pressure passage through the heads, which is not acceptable. I have read that others have used these gaskets without any problems, so obviously they have a different way of setting the gasket onto the block than we have (we use our hands). We had no problems using 968 gaskets unless the engines had detonation......which might concern the guys with the superchargers), and we have returned to using these gaskets in engine construction. Sure, it is a pain in the neck to correct the reversed cooling direction on the 5-8 side of the engine, but this is much better than dealing with the "928 Rainbird" effect.

Others, in Southern California have tried the Cometic gaskets (you out there Rob?) and also have the "928 Rainbird" effect.

greg brown

Tony

Ive still got set of the "faulty" cometics on my shelf...one of these days i will exchange them.
Kock on wood, but im at 159K..stock gasket..9-10psi. and i may just put a new stock one in when the time comes.

928SS

good idea based on the tiny sample set of 928 rennlisters in the last 72 hours/ what we're seeing here alone - it seems arguable there's a definite trend/issue... no wonder they'll take them back w/out much fuss

hopefully they'll learn from this and create a better product. in that regard - mine are leaking coolant in the right rear corner btwn last two cyls and the rain man noted where they leak oil - but where have the other coolant oil leaks been?? ketchmi?? tim??

I'll call them on monday and see what happens/they were pretty easy to work w/in the past, imo. maybe we can get one of them on the list to tell us what they've learned/any magic tricks... might be cool or maybe they'll just give us free stickers (or catch pans)

fwiw, I got 135k out of my stock OEM set before they started leaking oil...

928SS

guess the date was 08/04 - not spring 05... part numbers: C5783/C5782 (left/right).

here's the response from cometic/Kevyn:
"Each case must be taken individually. If they have a concern they can contact me
directly as well via this e-mail address.
Kevyn Kistner
Technical Sales
Cometic Gasket"

website: http://www.cometic.com/ (go to the "contact us" page to send an email)
guess they don't want to share anything here, so we'll have to respect that....

SwayBar

Rob, I'm sorry to hear about your engine.

When you take it apart, make sure to measure the bore at the top of the cylinder(s) to check for possible ballooning from the hydro-lock.

SwayBar

Are you sure about this? I was not aware he had any problems with them.

I'm curious because Cometic's are going into my wet-sleeve motor.

WICruiser

It would be a good idea to pull the plugs to confirm which cylinder has the lock condition before you pull it apart, makes it easier to feel comfortable that you checked everything for that bore before it goes back together.

atb

On the RMT motor, I did not put the Cometics in dry (Yes I ignored the instructions). I used a spray on copper-based gasket sealer. The deck and cylinder crowns were sprayed, the head mating surface was sprayed, and both sides of the gasket were sprayed. Two coats each, with about 30 minutes cure time between coats. After the heads were torqued the block was allowed to sit for a several days before anything else was done in order to allow the gaskets to take a set.

So far, so good. But no boost yet. I guess we'll know soon.

928SS

we'll be checking everything for sure

from what I've learned so far - the cometics require an "50 RA" finish on the surfaces, according to their website. given it's a bugger to do w/our stuff and not a Pcar std procedure - this MAY be a source of some issues folks have been having... also they are supposed to be installed dry, although some guys have been using stuff on them and claim it's the only way they'll work...

I had a hot rod 440 mopar that simply wouldn't stop valve cover leaking till I put cheap cork gaskets/none of the premium stuff would hold... I'm kinda also wondering if there's a design issue on our motors that makes them difficult to seal in a similar way... some stuff is fickle by nature, and we all know dr P's gang had a method for everything for a reason (well, maybe except for the 951 hehehe)

I'll be sending my set to cometic for analysis... guess we'll see what happens.
got'er on the trailer now, going down tomorrow.... keep those candles burning!!

928SS

hey adam, that beast should be a hoot

fwiw, my motor sat for about a month before I got the car down for them, but gaskets went on dry. hmmmmm... iirc, garrity also uses something on his too... not sure what devek uses/used...

hacker-pschorr

Don't worry about it You know Todd - Cometic doesn't even make a gasket for the bore size he runs - yet he is still using a Cometic gasket.