My Cometic gasket failure

[FreddieWilliams]

I decided to give the cometic gasket a try on my stage 1 motor when getting it ready for the West Coast Nationals in Vegas.
I was hoping to have a set of the new TA aluminum heads on the motor for this event but you know that didn't happen.

I decided to port a set of stock iron 8 bolt heads and bolt them on for now.

The stage 1 block has been drilled for the extra head bolts (14-bolt) and the cometic gasket 3.8L I used had the 14-bolt hole pattern as well.

Anyone know what the center of the cometic head gaskets are made of? It appears to be aluminum to me.
If so, what is the temperature aluminum start to soften/melt? ~1200-1250 degF??????

What sort of temperatures does the combustion chamber see? I saw ~1500 deg F on my EGT gauge.

Do you get a since of where I'm going here?

I'm wondering if my stock heads lifted and the exhaust/combustion gases caused the aluminum core to melt/warp severely. Thus leaving a path for exhaust gases to escapes when the head settled back down.

Current Combo:
TA63 Turbo
55# inj
Mod ECM w/ P&H drivers (by BB)
Stock ported Iron heads (8 bolt)
3.8L Stage 1 block (14 bolt)
CC 212/212 roller cam

State of tune:
Boost =~20-21psi
FP = 46psi static (55# inj)
O2 = 800mV to 850mV (Directscan)
Gas = VP C16 (10 gals)
EGT =1480 deg F
Timing = 28 deg

The gasket was gone right at the launch. I heard it leaking all the way down the track.


I plan to flow the injectors. Perhaps the #3 inj is not flowing up to par.

Click here to see a picture of the leak:

TIA

 

[Russ Merritt]

Why is it the gaskets fault? Coulda been a hundred other things. I run the same gaskets and have had no problems at all. NONE! I'd look elsewhere for your problem.

 

[FreddieWilliams]

Russ,

I never said it was the gasket's fault. The reason I decided to run them is because of all the success people like yourself have had using them.
I will also add the passenger side head gasket seems to be perfect still. Only the #3 cylinder on the driver side is leaking.

The end result is the driver side gasket is leaking exhaust. The reason for the post is to get some ideas on where to look for a cause.

I plan to check the injectors by getting them flowed to see if one was running lean in that hole.

ARP pro series head bolt, torqued to 85 ft/lbs, were used. Moly lube on the head/washer and ARP teflon thread sealant on the threads.

If you have any suggestion of something else for me to check into, please post your recommendations.
They will be greatly appreciated.

 

[Russ Merritt]

Silly me, I thought I knew where you were going with it.

OK, ready? You could have something with the injector, perhaps. Both deck and head MUST be flat! I assume you know that already. I also clean both surfaces with brake clean prior to installation. I like studs better than bolts but bolts do work. You came up to torque in correct sequence and in increments? I usually do it in tens starting from 50#. I went to 90# on my GN1s. Next check the coil pack, wire, plug for that cylinder. How bout your boost guage? Make sure it doesn't leak giving the wrong reading. If it was leakin before you ever ran it down the 1/4, something is big time wrong and should be easy to find.

 

[bruce]

Originally posted by FreddieWilliams

O2 = 800mV to 850mV (Directscan)

Have your got a datalog of it?.
Or just a log running whatever chip your running?.

I'd like a gander if so.

 

[FreddieWilliams]

Bruce,

I could send you my Direscan file but you have no e-mail address.

 

[S2V6RACER]

Not the gaskets fault. Just isn't any way you are making that much power to be lifting the head IMHO, especially at launch. I would check the heads themselves. I have seen sets that just keep blowing gaskets IMMEDIATLEY.

Given your facts on fuel, boost, egt you are not detonating the motor.

 

[STP]

Running 11's you shouldn't have any trouble lifting the head like Ted said. After no less than 4 Felpro 1007 locwire gaskets in a two month span, I went with 14bolt heads and Cometics. Heads would lift at anything over 23psi on my 276" engine and pressurize the cooling system. Could have been a reciever groove problem, but who knows.
How much has been milled off the heads? Did you run some allen head set screws into the blind holes? Sounds to me like the heads have lost their clamping ability, are not flat, not torqued properly, or you perhaps need a new set of studs not bolts. According to ARP and a few others I've talked to, the bolts can lose their strength after torqueing several times. I would check the head for flatness and buy a set of studs. Stick with the cometics, works for me. Scott

 

[FreddieWilliams]

Thanks for all the ideas guy's.

Just to answer a few check points you guy's have pointed:

Stock ported (8-bolt) heads have been resurfaced before installing.
Block was surfaced as well. Both surfaces were troughly cleaned before installing the new head gaskets.

New ARP Pro head bolts were installed and torqued in 10 ft/lb increments starting from 25ft/lbs to 85ft/lbs

Set screws were installed in the unused hole but were counter-sunk will below the deck surface.

Dowl pins were also checked to insure they were not too long and would hold the heads up from the block deck.

 

[STP]

Well....What did the spark plug look like? And what's the bore?

 

[Scott231]

Freddie -

You need to pull the heads off and ascertain if in fact that is the only cylinder that had a problem. (Throw a straight edge on there and verify that they are still flat!) Unfortunately the drive home eliminated the chance to read spark plugs (unless you did that at the track and haven't told us your findings). If you have more than one cylinder failing/failed, I would ask "What air:fuel ratio's you are running?"

Don't forget that #3 is the one that is infamous for heat-damaging the injector wires to that cylinder's injector thanks to the EGR that is (or used to be) there. Just because the injectors may check out on the flow bench...is the pulsewidth getting actuated at that injector?

If your EGR is plugged, is there any chances of a leak? (i.e. too much oxygen getting to that one cylinder?)

Another SWAG - did you degree the cam on each cam lobe? Again, #3 is the problem child on a TR engine.

Good luck and let us know what you find when you pull the head.

 

[The Radius Kid]

Dang it all Fred,looks like it was a headgasket afterall.
You might want to compare[if possible]your 14 bolt gasket to the shape and construction of the 8 bolt version.
I'm guessing that the 14 bolt failed because the extra bolts weren't there to support the area that failed...an "unsupported bridge" if you will.
Scott's right,I would wait and see what the other cylinders look like before passing judgement.

 

[FreddieWilliams]

STP & Scott,


The bore size is 3.840

I did not think to check the plugs while at the track so that's not in option after the drive home as you stated.

Both matting surfaces were freshly machined when the gaskets were installed so I have no reason to believe they were not flat to begin with (heads were done by my local machinist I have used for years & block done by Kenny D.).
The car never went over 200 Deg F on the drive up to Vegas climbing the hills.

The egr passage was thoroughly cleaned before installing the intake manifold and the #3 inj harness has been re-routed years ago to prevent contact with the egr valve.
However, I do plan to purchase a new 14gauge inj harness from Casper’s just to cover any hidden issue that might exist.

The cam was degreed by Kenny D. as part of the short block buildup and I did not verify it myself.


Radius Kid,

Do they make an 8-bolt version of this gasket?
Neal Steward was also thinking along the same lines regarding the extra bolt hole being unsupported on a composite gasket but I would think this metal cometic gasket would not have this issue.
Well, I'll just have to wait until I have the energy to pull the engine and see.



Thanks again to you all for your continued suggestions.

Keep them coming!

 

[STP]

They did not make an 8 bolt gasket for my 4.015 bore. If that helps you any. Sounds like you covered all the bases prior to install. How much has been milled off the heads? Scott

 

[FreddieWilliams]

STP,

The heads had been milled twice. Approx .005" each time so a total of .010". I made sure the bolts did not bottom out if that's were your going.

I could not use the standard stage 1 kit from ARP. Most of the kit did work but the short outter bolts were a little too long. I measured the head thickness and had ARP find a bolt in there open stock to fit my needs.

 

[STP]

Well I'm at a loss...I have seen heads lose their clamping ability due to too much material being removed from the head surface. Just wasn't enough "meat" left in the head for the studs to effectively hold them down. This was on a friend's turbo Mustang though, may or may not apply. .010 shouldn't be anything to worry about though. Good luck, I'm all out of ideas. I was never able to keep the 8bolt heads on my block for more than a few passes at a time. Could have been a loc-wire issue, but who knows. Put the 14 bolt GN1R's on it and no more problems...*fingers crossed*

 

[The Radius Kid]

I would think that they do.They make quite a slection of gaskets including head gaskets for the Dodge Intrepids.
You might want to contact Tommy at Champion.I believe he sells these.
He should be able to give you a positive answer.

 

[EightSecV6]

Did you use stock block ARP or Stage1 ARP head bolts? The stock type bolts are longer as the threads in the block are about 3/8" down before they start, stage 1 blocks have the treads all the way to the deck. I dont have any parts in front of me but could it be possible that you used stock type ARP bolts and the bolts are bottoming out (not at the bottom of the bolt, I know the holes are not blind ) with the shank portion of the bolt against the deck before the heads are fully torqued?

 

[Intercooler]

Bill is right on that...I had a set of Stage 1 head studs that I sold to a board member unknowingly. He told me they wouldn't work on his stock block! I think they were shorter and had a different part number. Good luck!

 

[FreddieWilliams]

EightSecV6,


Thanks for asking and yes, I did order the wrong bolts originally (stock 86/87 bolts) but found they were too long for the stage block very quick.

I then ordered the Stage 1 bolt kit 77-85' and checked each bolt length to insure the shank did not bottom out. All but the shorter outer bolts were fine. I had to measure the head thickness and contact ARP to have them pull the correct size short bolts out of their open stock.

I will still check this issue when I pull the heads. Perhaps one head was thinner is bottoming out.

Thanks for the reply.