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Old 08-29-2019, 07:00 PM   #1
poulrais
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Default Cometic MLS head gasket problems

Brand new build... Very clean B230 NA block, decked and bored. 16V head, resurfaced and tested. Yoshifab forged 16V pistons and rods. 0.045 Cometic MLS head gasket and ARP head studs and bolts. Torqued to ARP specs with their lube.

Started the motor to get a heat cycle in. Noticed that the break in oil was somewhat creamy. What the hell! Maybe some condensation build up in the engine because it was left sitting in the tuner's garage driveway for a good 2 months waiting to be wired for the MS3.

Dropped the oil. Restarted, let the heat build up some. Oil checked and it comes out even creamier. Damn!!!

We pondered on either lifting the cam carrier and re-torque the head studs or lifting the head from the block to check the head gasket. I bought a regular Elring HG just in case the Cometic is crapped. We finally took the decision to lift the head cause removing and reinstalling this cam carrier is such a pain in the ass and I didn't want to put in all this work and have to take the carrier off again if it still doesn't seal right.

So... Here are the pictures. It's quite obvious that the HG wasn't sealing correctly because of the differences in the shapes of the coolant and oil passages between the head and the block. The embossing on the edges of the holes in the HG for these passages is preventing the gasket to seal the spaces between the coolant and oil passages.









Should I notify Cometic about this and ask for a refund and for them to reimburse some of the expense for removing/reinstalling the head? They will probably tell me to go take a hike but I'll never know if I don't try...

Will the Elring be able to hold a good 25 PSI of boost with the ARP studs and a good tune? There will also be knock management configured on the MS3.
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Old 08-29-2019, 07:08 PM   #2
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Those ports in the head don't look right, how much has it been cut? I was holding 25psi on a big cooling port 160 head with an Elring HG and ARP studs. I've also installed a normal head gasket upside down but that leaked coolant out under the intake.
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Old 08-29-2019, 07:10 PM   #3
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Those ports in the head don't look right, how much has it been cut? I was holding 25psi on a big cooling port 160 head with an Elring HG and ARP studs. I've also installed a normal head gasket upside down but that leaked coolant out under the intake.
I'll have to ask the machine shop... What do you mean by "they don't look right"?
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Old 08-29-2019, 07:21 PM   #4
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He says the head was shaved around .0035 but we don't know if it was shaved in the past before we did.
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Old 08-29-2019, 07:46 PM   #5
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I thought those oval shaped ports were supposed to be circular?
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Old 08-29-2019, 07:52 PM   #6
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I thought those oval shaped ports were supposed to be circular?
I doubt it...
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Old 08-29-2019, 07:55 PM   #7
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This is the cracked 530 out of my shed, sorry for the giant size. I'm wondering if yours was cut too far.

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Old 08-29-2019, 09:08 PM   #8
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The 16v heads have oval oil drain-back holes, nothing wrong there.
Did you install the gasket upside down?
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Old 08-29-2019, 09:18 PM   #9
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The 16v heads have oval oil drain-back holes, nothing wrong there.
Did you install the gasket upside down?
Nope... I don't think it can be installed upside down?
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Old 08-29-2019, 09:19 PM   #10
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What is the RA of the surface of the head and block?
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Old 08-29-2019, 09:40 PM   #11
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Quote:
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Nope... I don't think it can be installed upside down?
I did it with an Elring. You can see the witness marks on the gasket where the ports don't match up. Are the 16v gaskets different than 8v?

Last edited by VB242; 08-29-2019 at 09:50 PM..
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Old 08-29-2019, 10:27 PM   #12
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Quote:
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I did it with an Elring. You can see the witness marks on the gasket where the ports don't match up. Are the 16v gaskets different than 8v?
No... same part number.
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Old 08-29-2019, 10:33 PM   #13
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Quote:
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What is the RA of the surface of the head and block?
I have no idea... Is it common for a machine shop to check this value? The head surface is very smooth. Almost polished. The block’s surface I don’t know.
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Old 08-29-2019, 11:57 PM   #14
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So, the gasket can only really go on one way. The locating dowels in the block keep the gasket on correct in that dimension (both dowels on the exhaust side), plus the oil feed hole is towards the front, so there's really no way to get it in wrong.

Next question...you do have the locating dowels in the block right? If not, that gasket could be off center.

The machine shop definitely needs to know a surface finish for the block and head so they know how to cut it. Just from those pics the head doesn't look too bad, but it's hard to say for sure. I believe the spec for Cometic's is 50-52ra.
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Old 08-30-2019, 12:22 AM   #15
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I just looked at my penta 16v head looks the same on those holes, it's been resurfaced also. Why does the mark of the oblong hole go the other way in your pics compared to the way you have it lined up? Did you put the gasket on the other way? Oblong hole goes down on the head but up on the gasket marks next to it? Looks like the gasket was on the other way compared to the way you took it with the pics. Upside down..
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Old 08-30-2019, 04:14 AM   #16
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50ra is the same as 240 grit, according to Google anyway.
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Old 08-30-2019, 06:42 AM   #17
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I just looked at my penta 16v head looks the same on those holes, it's been resurfaced also. Why does the mark of the oblong hole go the other way in your pics compared to the way you have it lined up? Did you put the gasket on the other way? Oblong hole goes down on the head but up on the gasket marks next to it? Looks like the gasket was on the other way compared to the way you took it with the pics. Upside down..
are you referring to the first pic? If so, on that picture, if you fold the gasket to the head, that's the way it was installed.
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Old 08-30-2019, 06:47 AM   #18
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Quote:
Originally Posted by gsellstr View Post
So, the gasket can only really go on one way. The locating dowels in the block keep the gasket on correct in that dimension (both dowels on the exhaust side), plus the oil feed hole is towards the front, so there's really no way to get it in wrong.

Next question...you do have the locating dowels in the block right? If not, that gasket could be off center.

The machine shop definitely needs to know a surface finish for the block and head so they know how to cut it. Just from those pics the head doesn't look too bad, but it's hard to say for sure. I believe the spec for Cometic's is 50-52ra.
Yes the dowels are on the block. I will check with the machine shop for the RA but the Cometic is obviously not going back on the head. We putting on an Elring this time. Even though the holes on the Elring match the ones on the Cometic the lack of embossing will mean that the Elring is going to seal this thing right.
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Old 08-30-2019, 09:35 AM   #19
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Hmm, that seems really strange with the holes being that far off on 2 different gaskets. I did find that on a couple cooling holes on the B20 gaskets as well though, with the front 2 holes only having maybe 1/8" of actual flow due to the offset. Elring and Cometic had the same holes, Victor I think it was had a little better alignment.

How well does the gasket line up with the holes in the block?
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Old 08-30-2019, 09:37 AM   #20
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agreed that it is strange, I can't really see how it could go in properly oriented and end up clamped like that. I've used two Cometics on my 8v b230, first was probably in 2015 second was this year - never had issues.
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Old 08-30-2019, 09:50 AM   #21
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agreed that it is strange, I can't really see how it could go in properly oriented and end up clamped like that. I've used two Cometics on my 8v b230, first was probably in 2015 second was this year - never had issues.
I will try to take some pictures of the gasket on the head and on the block...
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Old 08-30-2019, 09:50 AM   #22
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I've had some issues with Cometics, but not misaligned holes. Mostly I'd get compression leaks after 5 - 10K hard miles.

(edit: on 16V heads, two of them, and different blocks)
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Old 08-30-2019, 09:51 AM   #23
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Quote:
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I will try to take some pictures of the gasket on the head and on the block...
would be interested to see. I don't think you mucked it up, it's basically impossible to put it on wrong.
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Old 08-31-2019, 09:50 AM   #24
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There were some fitment issues with the rivet locations on the mls head gaskets. Also there is some suggested coating to use. Check out the prep and installation on Stealthftis pbase gallery. https://pbase.com/stealthfti/tsna
There is coating the head gasket and also he removes the rivet tabs because they get in the way of the head gasket seating.
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Old 09-03-2019, 01:28 PM   #25
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There were some fitment issues with the rivet locations on the mls head gaskets. Also there is some suggested coating to use. Check out the prep and installation on Stealthftis pbase gallery. https://pbase.com/stealthfti/tsna
There is coating the head gasket and also he removes the rivet tabs because they get in the way of the head gasket seating.
Good info there.
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