Alternative to cometic head gaskets?
Thread Starter
Joined: Jun 2006
Posts: 1,429
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From: Spring Hill,Kansas
Alternative to cometic head gaskets? I have been thinking about buying a set of cometics but I hear how hard they are to get sealed up. Are there any other head gasket companies out there than can make custom gaskets that may be a little more 'forgiving" as far as sealing up?
I haven't done any research into what sealing trouble people are having, but I can say that I have used Cometics in a lot of builds and have had ZERO issues. Most of these builds are high compression or power adder engines and I have yet to see one leak. Cometic = money well spent.
people who say that are the people who don't properly clean the gasket surfaces. Get it clean!!! fresh new razor blade and take your time feel all around the block to make sure no peices of debris are left behind, then what I do is use a cloth and brake clean to remove and dirt or oil on the surfaces, you want them to go on dry.
Also get good hardware.. ARP
only other thing is to chase the threads in the block so you get a good tight torque on the bolts to hold everything in place
Also get good hardware.. ARP
only other thing is to chase the threads in the block so you get a good tight torque on the bolts to hold everything in place
I dusted mine with Hylomar spray. Two key things are flatness and surface roughness. Fel Pro makes an 0.041" gasket too which isn't the same design. Some guys have had that leak as well.
The GM gasket is more forgiving but obviously not as thin.
The GM gasket is more forgiving but obviously not as thin.
Very few people have problems with the Cometics when they're done properly. I killed 2-3 sets of Felpro gaskets on my vette before swapping to the cometics. If I'm not running a GM gasket I'd buy Cometic without a doubt.
Give us a call if we can help you, can we can tell you our Cometic install procedure & see if we can help
Give us a call if we can help you, can we can tell you our Cometic install procedure & see if we can help
__________________
Jason
Co-Owner, Texas Speed & Performance, Ltd.
2005 Twin Turbo C6
404cid Stroker, 67mm Twins
994rwhp/902lb ft @ 22 psi (mustang dyno) www.Texas-Speed.com
Jason
Co-Owner, Texas Speed & Performance, Ltd.
2005 Twin Turbo C6
404cid Stroker, 67mm Twins
994rwhp/902lb ft @ 22 psi (mustang dyno) www.Texas-Speed.com
If your Cometic head gasket leaks you did not do proper preperation before you installed them...you must get the deck surface of the block and the heads absolutly clean and dry... and the same with the head bolt holes ... that is something that you must do no mater what brand of head gasket you install....nuff said.
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FWIW I installed cometics on a one of my best friends' cars and they leaked out the back of the head. I challenge anyone who says we didn't "prep it right" because we had a brand new block and brand new AFR heads. The only thing I can think of is that the first time we didn't go heavy enough on the copper spray. But once we got them sealed they were never a problem. There are lots of head gasket options out there now, the good thing about cometics is that you can get whatever thickness you want. 
Used cometics for many years now and never sprayed copper coat on any of them ... been hot rodding since the early 60s and have never had a head gasket leak on a street car or race car.
Very few people have problems with the Cometics when they're done properly. I killed 2-3 sets of Felpro gaskets on my vette before swapping to the cometics. If I'm not running a GM gasket I'd buy Cometic without a doubt.
Give us a call if we can help you, can we can tell you our Cometic install procedure & see if we can help
Give us a call if we can help you, can we can tell you our Cometic install procedure & see if we can help
Felpro MLS (p/n 1160 (3.945"), 1161 (4.100"), and 1162's (4.175") all R&L's), or their composite (p/n 1041), .041" thick x 4.135" has worked well for me on most performance NA apps. The MLS has held 20 psi on a 4-bolt block with no issues. The only snag with Felpro is that they are only offered in one thickness from the MLS standpoint, but they have different bore sizes to choose from. They also have the 6-bolt gaskets as shelf items. P/N 26472's and 26473's both R&L's and measure .053" compressed like the others.
GM works well too, same deal though, only one thickness. But there is usually a reason for that.....has to do with the 'active' layers of the gasket. A MLS gasket with more 'active' layers is a better head gasket and will tolerate more headlift - hence the GM 7-layer. 'Stopper' thickness is also critical, usually a thicker stopper is stronger and can take more abuse.
Usually the headgasket fails prematurely from install procedure, the tune and/or detonation (but "I swear my engine is detonating") LOL!
I only use the Cometics when the thickness selection is critical, but in most times it can be worked around. They have a good marketing approach for offering any bore size and thickness, therefore they are popular and in most cases work pretty well. If it is a HIGH HP deal, I would look to Felpro or GM.
There you go, all manufacturers have been covered now. This thread could go on forever. But there is my .02, as always worth half a cent!
GM works well too, same deal though, only one thickness. But there is usually a reason for that.....has to do with the 'active' layers of the gasket. A MLS gasket with more 'active' layers is a better head gasket and will tolerate more headlift - hence the GM 7-layer. 'Stopper' thickness is also critical, usually a thicker stopper is stronger and can take more abuse.
Usually the headgasket fails prematurely from install procedure, the tune and/or detonation (but "I swear my engine is detonating") LOL!
I only use the Cometics when the thickness selection is critical, but in most times it can be worked around. They have a good marketing approach for offering any bore size and thickness, therefore they are popular and in most cases work pretty well. If it is a HIGH HP deal, I would look to Felpro or GM.
There you go, all manufacturers have been covered now. This thread could go on forever. But there is my .02, as always worth half a cent!
Last edited by helicoil; Feb 7, 2010 at 11:32 AM.
The GM gaskets seal the best from what I've seen in my research. I've also heard of countless problems with Cometic. Of course, countless other people will claim they've used Cometic without problems. I think most people will agree you need to do extra prep with Cometic gaskets.
Cometics work well if the head and deck are prepared properly. Mating surfaces are recommended to have a 50 RA finish or finer IIRC.
I think GM MLS are a little more forgiving and I have no experience with Felpro MLS. The oldschool Felpro stuff always worked well though....
I think GM MLS are a little more forgiving and I have no experience with Felpro MLS. The oldschool Felpro stuff always worked well though....
