Seems like I've been hearing alot about leaky cometic head gaskets lately. What's the word on this? I have a set sitting here ready to go on my 422 but I've been thinking about getting a set of felpro's instead. Help me make up my mind. I can't afford down time for a leaky gasket and wait for a new set to get here.

 

go ahead and use the cometics.
i would never use anything other than a cometic gasket on my car. the leaking happens when the middle layer peices are not alligned or properly seated. when the oring portion of the middle layer doesn't sit flush in the surrounding layer that's when the leaking occures and you junk the gasket if you tighten the heads down on them like that.

hope this helps

 

Thanks for the explanation. I'll keep my eye on that when I put them in.

 

Make sure to get the "HP" Cometic gasket. Don't buy the standard Cometic gasket. The HP stands for high perfomrance and will hold up to a lot more horse power. The standard gasket will not hold boost..... <img border="0" alt="[bang head]" title="" src="graemlins/gr_banghead.gif" />

 

As a added note; make sure that both the deck surfaces (head and block) are absolutely true. The MLS style gaskets don't absorb too much in surface imperfections.

Stick with the HP's! If the engine is still on the stand it will be much easier to install the HP's with the O-ring.

 

I had a set leak on me. Might try the Felpros now.

 

Felpros are junk i had a set on for 2500 miles and the water jacket blew out. Use the cometics just make sure every thing is true and that u put them on right.

 

Maybe JPR will chime in here. I am going through the same dilemma. I have a big bore and was going with the cometic until I heard of many of them leaking. JPR told me that 4?? of his 422's leaked because of the Cometics. He said he is now using Fel-Pro's and haven't had a problem, based on that I went with the heavy duty Fe-Pro and am keeping my fingers crossed.

 

Ive used Cometics on three seperate occassions. All worked flawlessly. They are a very tough gasket. I have blown them a few times and each time all they did was allow the coolant system to pressurize slightly. The car was even drivable on motor...just couldnt spray or it would pressurize the coolant system. And this was after spraying a 325 shot on my 383...probably around 725 rwhp with too much timing and lots of detonation.

 

I hope that JPR does chime in we had many problems with the cometic's. Personally I wouldn't use them again i had TWO sets leak on me and got no restitution. So i guess its just personal choice. Ask JPR for any more info.

 

They had a faulty design on the 98 head gaskets because they didn't seal all of the coolant passages. My friend showed them the error in their design, and now the correction is being used. I am about to use these on my engine. I just got both surfaces machined to ensure a perfect mounting surface. I am not worried about having them leak. They appear to be of very high quality pieces.

 

Just used a set on a 427 - definetly leaked coolant. Will never use again. Head (LS6) and block (C5R) were (and still are) perfectly true. The stock bolts/torque specs are apparently not enough for these gaskets. Replaced with fel-pros, no problems.

 

I had a problem with my Cometics on a 01 TA.Loss coolant,oil in the coolant.Replaced with Felpro's.
Also installed a set in a friends car and his are holding up fine.
A problem or fix I noticed is that you need to torque Cometics atleast 4 times to get them to compress all the way.If this is not done they can easilly leak.

 

We built 3 engines with Cometics, I am a very detail oriented motor builder, our block / head surfaces were true, needless to say, almost 1,000 dollars worth of Cometic gaskets leaked, one motor pulled, pressure tested, decks checked, (upon Cometics advise) re-installed with Cometics and leaked again. I switched over to the Fel Pros which were not available at the time we originally started these projects, still in use with -0- problems to date so all is well now. Situational? doubt it.. Installers error? Fat chance.. All I will say is I am the last person on earth to say a bad thing about another company, BUT when I lodge several complaints about a product and there is no refunds/apologies/replacement gaskets, I get a little upset. This above mentioned situation had me apologizing to a few people because I accused them of shoddy machine work for no reason. Sorry for the vent, but I was asked buy 3 board members to weigh in on this subject.

Joe Prince.

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by JPR:
<strong> We built 3 engines with Cometics, I am a very detail oriented motor builder, our block / head surfaces were true, needless to say, almost 1,000 dollars worth of Cometic gaskets leaked, one motor pulled, pressure tested, decks checked, (upon Cometics advise) re-installed with Cometics and leaked again. I switched over to the Fel Pros which were not available at the time we originally started these projects, still in use with -0- problems to date so all is well now. Situational? doubt it.. Installers error? Fat chance.. All I will say is I am the last person on earth to say a bad thing about another company, BUT when I lodge several complaints about a product and there is no refunds/apologies/replacement gaskets, I get a little upset. This above mentioned situation had me apologizing to a few people because I accused them of shoddy machine work for no reason. Sorry for the vent, but I was asked buy 3 board members to weigh in on this subject.

Joe Prince. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Doesn't take a geniues to realize this guy is right. Look how many posts show up on leaky cometics. There can't be that many install errors. Few people have trouble with stock gaskets on stock bore motors.

 

Below is a link to a thread I posted on another forum regarding my problem with Cometics during a h/c job I did on my '02 C5 and the final solution.

http://forums.corvetteforum.com/zerothread?id=489800

 

I work next to Lingenfelter shop here in Dallas. They will only use Cometic on all their motors. They have many 427 big bore twin turbo motors, putting out over 600 rwhp. They have never had a problem. They said that they spray permatec HI TAC (same as the copper sealant spray)on all the gaskets before using. Never had a leak. I have used Cometic on all my motor rebuilds and never had one leak. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

<small>[ March 26, 2003, 11:12 AM: Message edited by: Fastest 35th SE. ]</small>

 

<img border="0" alt="[bang head]" title="" src="graemlins/gr_banghead.gif" />


I just got Cometic's......Hopefully I don't have any problems.....I wlll torque those dang things till the cows come home....

 

Thanks for the reply JPR. Is the Felpro a mls gasket as well?

 

Hey Ferris,
The Fel Pro's are not MLS's there regular run of the mill flat composite gaskets with firing rings.

Joe.