Cometic HG Failure

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Cometic HG Failure

Post by supakat » Fri Feb 08, 2013 7:32 pm

Hey guys, just wondering if any of you guys had failure like this. I am just happy my bottom end is good though.

This guy had the same issue.

http://www.yellowbullet.com/forum/showt ... p?t=472982

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Post by F1Altima » Fri Feb 08, 2013 7:57 pm

So basically the entire gasket failed around every cylinder? Epic fail. I'm currious to know if it was over/undersized. Usually when a head gasket fails because of tuning it gets blown out near one cylinder:
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That headgasket failure looks like assembly/over under sizing error..
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Post by jholman05 » Fri Feb 08, 2013 7:59 pm

I'm about 2 weeks away from assembling my built long block... I have a cometic sitting on a shelf in the garage but now I'm getting scared. I had the head and block resurfaced for a metal headgasket and I'm going to be running the saturn main/ka head studs with 20psi. Wonder if I should suck it up and just get a cosworth?
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Post by supakat » Fri Feb 08, 2013 8:16 pm

F1Altima wrote:So basically the entire gasket failed around every cylinder? Epic fail. I'm currious to know if it was over/undersized. Usually when a head gasket fails because of tuning it gets blown out near one cylinder:

That headgasket failure looks like assembly/over under sizing error..
Just 1 and 4 failed. Block is .020 over. All Cometics are 90mm (.040 over) and Cosworth's are 90.5 (.060 over). If tuning did this, I know when this happened. I ran a 600cc bike but my tune was still in the making. Oh well, you live and you learn. Still happy I ran him though. :lol:
jholman05 wrote:I'm about 2 weeks away from assembling my built long block... I have a cometic sitting on a shelf in the garage but now I'm getting scared. I had the head and block resurfaced for a metal headgasket and I'm going to be running the saturn main/ka head studs with 20psi. Wonder if I should suck it up and just get a cosworth?
To tell you the truth, I would just for better insurance. They have a folded edge on the cylinder bore to help seal. Cosmetic do not have this and you can get one from THmotorsports for $164 shipped which is not bad. This is the first time in two years I opened up this motor and I am happy it is a little issue. I was going to try and use Felpro but eff it, I do not feel like testing the 500whp threshold limit. One member said he ran 600whp on felpro but I am just going to stay mls.

I have seen your vids and you don't baby your motor which is the way to go. Beat the living piss out of it and drive back home from the track.
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Post by Berserker » Fri Feb 08, 2013 9:38 pm

I ran @ 500 whp @ 25lb for 2 summers with felpro headgasket. Had 11mm arp bolts. I beat on the car alot. Only started leaking passed 600. But also b4 that had 1 fuel pump burn out and leaned out twice @ 20+ psi. That proly helped it leak.
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Post by F1Altima » Fri Feb 08, 2013 10:28 pm

How come all four pistons are clean around the edges and dirty in the middle?
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Post by supakat » Sat Feb 09, 2013 7:48 am

Berserker wrote:I ran @ 500 whp @ 25lb for 2 summers with felpro headgasket. Had 11mm arp bolts. I beat on the car alot. Only started leaking passed 600. But also b4 that had 1 fuel pump burn out and leaned out twice @ 20+ psi. That proly helped it leak.
I am trying to disregard this lol. I don't want to resort to felpro just cause I don't feel like opening this motor again if I have a hiccup in boost. But if all else fails, I still have this option.
F1Altima wrote:How come all four pistons are clean around the edges and dirty in the middle?
I see what you are talking about. With e85, it has this gunk. It was caked on my head, valve, etc. It would make its way into the chamber and it is like burnt sugar on the piston tops. Hard and crusty. I had to scrape it off on my head when it was still soft and caramelized. This explains the smoking I would have sometimes. I thought it was my turbo seals going or valve stem seals at first. Another glad it is this causing the issue rather than something major.
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Post by PuNcHdRuNk » Sat Feb 09, 2013 9:35 am

i already posted this in your thread supa but i thought i would post it here as well. my cometic did the same thing except mine cracked out and peeled in between each cylinder, i ran it for about a year at low boost levels (10-15psi), when i started getting into the 20+psi range is when it failed. i have since went with a felpro and have had no issues for the last year and a half or so. when i do my teardown this year i will go to bigger studs and do the cosworth gasket because i have heard nothing but good things about thier gaskets.

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Post by F1Altima » Sat Feb 09, 2013 11:39 am

I thought e85 cleaned everything? I guess it's still a good idea to run water injection even with e85 to clean things up. Those hard deposits can heat up and lead to preignition, not a nice way to go...
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Post by supakat » Sat Feb 09, 2013 12:17 pm

Yea, I am going to try and scrape some away. 2 and 3 will be a pain to do but needs to get done.
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Post by TryingToTurbo » Sat Feb 09, 2013 2:27 pm

I just had an issue last night, that I still need to verify today, but I think it is a Cometic failure as well. I've been running the Cometic for a little over a year now, and am running 14 degrees of timing on 93 pump at 12-15psi on 9:1 wisecos. I dont THINK it was tuning, but maybe it was? To be quite honest, I am not a tuning expert by any means. But felt like I was running safe tming. If not, then at least you know where my failure came from. I'll probably get it pulled apart before too long, and post pics.
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Post by supakat » Sat Feb 09, 2013 4:38 pm

I am sure it was not the tune but it was probably bad gas. Then with the higher than normal cylinder pressures, HG failure.

Even though you want the HG to fail before rods/pistons, the cylinder pressure to make 500whp is high compared to 10psi and it should hold. Oh well, Cosworth is getting my money.
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Post by airman » Sun Feb 10, 2013 8:38 am

My cometic had the same issue in cylinder 1. Had to reuse it and it would push air into the coolant system under long-heavy throttle.
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Post by ViperGT » Mon Feb 11, 2013 2:07 am

cometic does make a gasket like cosworths with the folded edge just not for our engine maybe we should nudge them.
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Post by duncan351 » Mon Feb 11, 2013 7:48 pm

Cometic should trying selling metal exhaust gaskets or maybe even intake but stay the hell away from trying to make head gaskets. They are horrible. Been saying it for years. Want a good reliable ka engine, stay with Fel Pro.
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Post by i_slide » Mon Feb 11, 2013 10:00 pm

I've been running my Cometic with 11mm studs on wastegate 20-21psi (550whp). I had the block and head resurfaced prior install. Fingers crossed for when i change clutches and go for more boost!

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Post by wesamiss » Mon Feb 11, 2013 11:32 pm

I thought most of the guys here knew about this? There has been at least 2 other threads about it. I had already decided on putting a top of the line felpro gasket on my build. :3

In all seriousness, I have seen more than 1 thread about how these things aren't what they are cracked up to be. Also, I will be using a felpro on my build, this just confirms that the "top of the line" isn't what they are cracked up to be.
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Post by schmauster920 » Mon Feb 11, 2013 11:55 pm

Im on here too much and Supas issue is the first i have noticed with the cometic, some builds go under the radar perhaps
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Post by wesamiss » Tue Feb 12, 2013 12:44 am

maybe it was a different brand. humm i swear i have seen at least 2 other people having issues with cometic, i could be wrong though. i usually am.
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Post by schmauster920 » Tue Feb 12, 2013 1:25 am

Im usually wrong too, so theres still a good chance here
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Post by supakat » Tue Feb 12, 2013 5:29 am

wesamiss wrote:I thought most of the guys here knew about this?
I have not seen anyone post how they separated only saying they do not seal. Then 8 million people jump on saying your block and head were not decked correctly or some other retarded crap. At least now, we have a thread with quite a few members having the actual metal gasket rip.
schmauster920 wrote:Im on here too much and Supas issue is the first i have noticed with the cometic, some builds go under the radar perhaps
Yea, that is why I posted. I thought I was having issues with pressure seeping through the layers and I could separate the gasket and copper spray like v8's do. But when I took a closer look, the darn fire ring was lifted. I was like WTH.

All in all, the gasket held in terms on sealing. If this never happened, I know I would be pushing 25 psi. So if the edges were folded or a floating firing ring was used instead of an embossed ring, Cometic's would work.

Well the two members who I talk about with Felpro HG and 500whp setups chimed in. I am going to give Cosworth a try. I know it will work cause AndreEMS has been running his for awhile. He is around 840 whp now I believe and my other friend is running strong with 530 whp.
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Post by F1Altima » Tue Feb 12, 2013 2:06 pm

If you get the consworth please confirm it has a folded edge on the cylinder bore to help seal, instead of the stamped edge the cometic has. I saw pics of the consworth and it seems to have a stamped edge not folded edge on the cylinder bore, but maybe/hopefully it was a generic pic...
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Post by supakat » Tue Feb 12, 2013 3:40 pm

Will post it up. Apparently the gasket has the folded seal because my friend who recently got one told me that. I cannot find pics of the gasket up close.
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Post by schmauster920 » Tue Feb 12, 2013 4:49 pm

If i remember correctly I read about a folded wire core seal around the cylinders a long time ago when it was coming out
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Post by ViperGT » Wed Feb 13, 2013 12:24 am

lol my cometic leaked compression into water jacket N/A lol so i took off the head and copper sprayed it (should have done the first time) still good now. but ill probably also go to cosworth if this thing ever pops, and get new valve seats and a valve job done by a reputable machinist.
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Post by Miami240 » Wed Feb 20, 2013 6:34 am

... and this is why there are threads about Cometic gaskets being bad... not because of their quality, but because of their users. I have yet to have a problem with a Cometic in any motor.
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Post by supakat » Wed Feb 20, 2013 6:40 am

Mine lasted 2 years so I can't argue but this happened to one person I know personally, and another person in Ft. Lauderdale who he knows personally. One in Ft. Laud was making 700whp+. The gasket could be good and the issue could be the head lifting letting the embossed part break at the crease. It is just a learning experience for me.
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Post by jholman05 » Thu Feb 21, 2013 8:05 am

Miami240 wrote:... and this is why there are threads about Cometic gaskets being bad... not because of their quality, but because of their users. I have yet to have a problem with a Cometic in any motor.
Enlighten us :dunno:
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Post by supakat » Wed Feb 27, 2013 5:39 am

Got them in and installed yesterday.

The gasket is heavier than Cometic and feels sturdier as well. It is made up of 4 layers vs 3 layers Cometic. As you can see from the pics, the seal is rounder vs Cometic semi straight edge so it will not create a create a sharp crease and separate.

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Post by RosadoRacing » Wed Feb 27, 2013 11:04 pm

Same thing happen to me cylinder four from head lift i'm assuming. the motor ran fine only way I found out was when I changed the studs. do cosworth offer for .020 boreI only seen them sell for .060 I believe. My new cometic is holding up fine but I also want to go with cos in the future.

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