Cometic head gasket(s) failure

[Rick WI]

Sure wish Pat, at Cometic, was still around. Pat sent me a set of the new Cometic whiteseal gaskets this past winter for "evaluation". At least in my case they failed the evaluation. Been fighting a loss of cooling water into the motor, to the point where on Power Tour it hydroed a cylinder and took out a shaft rocker and pushrod. Although I had issues with the intake gasket sealing as well, due to I suspect a slight milling of the head as well as a .005 thinner head gasket, after resolving that it still huffed oil and water like crazy.

Tore the motor down this week and both head gaskets look horrible. Cylinder 6 and 8 were leaking coolant like crazy (6 was the cylinder I lost the shaft on) and each fire ring was delamed and appeared just like you'd imagine it would under HARD detonation. That would make sense if it detonated but never heard any. All the cylinders, except 6 and 8 look rich as hell with lots of oil in them. Each fire ring appears like it failed right into the bolt holes. This would be not as much of a surprise if after breaking in on the dyno we didn't retorque the heads, then after another few pulls on the dyno we didn't retorque again after cool down as well. All times they were tight. In addition I checked torque after power tour when replacing the intakes the second time as well as checked torque prior to tearing the heads off. All times they were spot on.

So the quesstion:

Absent detonation what else would cause the fire rings to delam and be pock marked like they would if detonation occured.

Anyone know who took Pat's place at Corteco? I have a couple of gaskets I'd like to shove up...I mean send to them for inspection.

Related to the intake. Learned a huge lesson that no matter how little you think a few thou is it really can screw up the relationship on the intake. Taking a skim cut off the heads to flatten and moving down .005 on the gasket was enough, in my situation to hang up the intake on the end rails and not fully compress the gaskets.

[Joekool]

A knock sensor can pickup detonation way before the human ear can hear it, just because you dont hear it doesnt mean it wasnt present. As for the oil, my first suspect would be the intake since you said it wasnt sealing right in the first place. Carbon build up from oil burning and over rich conditions will cause an increase in compression and can cause hot spots which can lead to detonation.

Check the rod bearings, if they look good then you could probably rule out detonation as the cause of the head gasket failure. Also what type of head and block where you using? (aluminum, iron?). Ive seen a head gasket failure where one that was designed for an iron head but used on an aluminum head get all distorted around the rings because of the aluminum growing too much/fast for the gasket.

I have feeling you just had a compound of failures that lead to the damage of your engine.

[Rick WI]

Thanks Joe, these gaskets are designed for the aluminum to aluminum application I was running them on. I have diagnosed already where all the oil was coming from, both the intake and the head gaskets unfortunately.

The damage indicated on the fire ring is not typical of what you would see from an engine that had mild detonation. This type of damage would have been heard, based on my experience. All eight cylinders show very extensive damage to the fire ring area. The drivers side bank being the worse.

The bottom end will be torn down and inspected due to water in the oil. All new bearings are on order whether it needs it or not, as well as new rings and a light hone on the cylinders.

[rsteele]

not to overstate the obvious. but that sounds like a costly evaulation. be nice to get reimburst for troubles like that. but if it wasnt for people willing to try out new products we wouldnt ever find anything out.

so is there any other problems with other cosmetic head gaskets


[This message has been edited by rsteele (edited July 21, 2005).]

[rscamaro73]

Get ahold of Monty and see what he has to say.....

'Crappy pieces for crappy small blocks'

Sorry your 'experiment' failed.....your pieces cost too damn much....

[Rick WI]

Yes, quite an expensive little deal I got going.

Hopefully Monty comes around as I know he's tried these as well. I do have a call into Corteco to discuss the issue as well.

The world though is setup where all they will do though is offer another set of gaskets.

[Quick69]

Rick,

You're not usign a gapless top ring are you?

Any reason you're not using a normal Cometic MLS gasket?

Are you talking Cometic or Corteco? You mention both names.



[This message has been edited by Quick69 (edited July 25, 2005).]

[Rick WI]

Chris, I typed Cometic by mistake. It's the Corteco Whiteseal gasket.

I am running Hell Fire rings gapped for for running nitrous. On teardown the rings look fine still but are being replaced. Rod bearings on 2 and 3 were toast but no damage to the crank or rods. All the other bearings look fine but do show signs of heat on the bottom.

It appears that cylinder #8 might have been detonating as it's darkened underneath (onset of the black death syndrome it appears). The piston though appears in fine shape, with no distortion of the combustion surface or ring lands. All the other pistons are in great shape. It's odd that one piston looks this way and none of the others. It's also odd if it is detonating as I have never had that issue before. My only thought is the O2 sensor might not have liked sucking antifreeze and oil vapors.

[camdoc]

<font face="Arial,Verdana" size="2">Originally posted by Rick WI:
Absent detonation what else would cause the fire rings to delam and be pock marked like they would if detonation occured.
</font>

Same thing that caught the OEMs when they went to non-asbestos gaskets in the early 90s!

[Rick WI]

I don't follow you. There is nothing evident on the composite portion of the gasket to indicate a problem. The fire ring on the Corteco (sorry about typing Cometic before) is no different than that of a Ferrea or Fel Pro.

[f-body]

Cometic MLS gaskets are used in turbo applications a lot of Mustang racers use them. The mating surfaces have to be dam near mirror smooth.
Felpro has an MLS Multi layer shim gasket and it can be used on rougher surface.
I hope Cometic gaskets are ok cause I just installed them but I plan on a retorque due to the new ARP head bolts.

[Rick WI]

I was tripin when I typed that, the gasket I have a problem with is the Corteco Whiteseal.

[Quick69]

I know a guy using a Cometic with 40 psi boost in a turbo application.

Cometics are great gaskets. Mr. Gasket is making a MLS gasket that is almost identical to the cometic.... available from Summit and Jegs... little cheaper.

I like using an MLS gasket sealant from chrysler available at any chrysler dealer at the counter.... it's a yellow spray can. Goes on like water and sets to a thick film... This will help if the head is not perfect in finish.

[SlowSBC]

Rick, sorry to be reading this. I have been using Corteco's gaskets for 2 season. The only problem I ever had was the original gaskets only had .001" white seal applied to them. I asked Corteco to add another .001" to the gaskets for aluminum motors. The reason is that aluminum motor sleeve's sit above the deck (unless you deck the block). Nevertheless the extra .002" total should not make a difference. My block is o-rings and I have never used these gaskets on a non-oringed block. I talked to LSM about maybe trying the Cometic gaskets.. They asked a simple question "have you ever had problems with copper gaskets?" I answered no.. They said to stick with coppers than. They have seen failures with both gaskets. Anyway off track there..

Did you pump the motor after you got done building it? Did you pump it after the breakin for referance numbers? On copper gaskets I always torque the heads down to spec, let the motor sit for 24 hours and loosen each bolt till there is no pressure and retorque the head. This seems to help the bolts from loosening after a few runs. Did you ever recheck the bolts after run in? (you may have posted it but I didn;t read every post.. Sorry )

[Dirt Reynolds]

Rick - I too was offered a set of the white seal gaskets for "evaluation." I declined simply because I've always had great results with Fel Pro's gaskets and maybe I'm just getting set in my ways, but I figured if it ain't broke don't fix it. I've run Fel Pros with steel and aluminum heads and have never had an iota of a problem.

Sorry to hear of your problems - sounds to me like something went seriously fubar with those gaskets. I'm glad I passed on them.



------------------
'Silver Bullet' 1977 Z-28 413" SB
11.73 @ 115.10 on drag radials
Old Vortec combo:
12.15 @ 110.52