JustAnotherVictim said:
I donno...I was going off this:
Seven M said:
Looks like a recommendation to spray it to me.... :dunno: His reply to me included my quote from an earlier post on the 1st few lines.
cometic gasket question
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I donno...I was going off this:
Looks like a recommendation to spray it to me.... :dunno: His reply to me included my quote from an earlier post on the 1st few lines.
JustAnotherVictim
Supramania Contributor
Seven M said:
Looks like he corrected himself, your quotes had that paragraph so I thought that's what you were reffering to. He did contradict himself though.
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JustAnotherVictim said:
He was trying to quote me in rebuttal...that's word-for-word what I said in post #15
JustAnotherVictim
Supramania Contributor
ok so if the dude doesn't want to do it then don't do it!!! all i know is that its working.
One guy that suggested it has a 10 second DSM with a MHG on his car and its been fine for a year and a half. he recommends it. I put it on and it aint done shit but form a good seal. Don't do it if you don't want to but i did it and its fine.
And if a manufacturer told you you didn't need Bearing for your rods on a rebuild if you use their forged rods would you listen to them???? be my guest my friend. All i know is that if spraying copper seal was so bad for them why does it say "for use with MHG Cork HG and Copper HG right on the can???? hmmm interesing
like i said do what you want but mines perfectly fine have a nice day
One guy that suggested it has a 10 second DSM with a MHG on his car and its been fine for a year and a half. he recommends it. I put it on and it aint done shit but form a good seal. Don't do it if you don't want to but i did it and its fine.
And if a manufacturer told you you didn't need Bearing for your rods on a rebuild if you use their forged rods would you listen to them???? be my guest my friend. All i know is that if spraying copper seal was so bad for them why does it say "for use with MHG Cork HG and Copper HG right on the can???? hmmm interesing
like i said do what you want but mines perfectly fine have a nice day
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Listen to JDub, he know what he is talking about. Instructions directly from Cometic attached.... but I'll just pull out the key point in question.
"Additional sealer is not required with Cometic MLS Head Gaskets. The outer layers of the gasket are coated with a .001" thick coating of viton (a high temperature flouroelastomer)."
The entire instructions are below if you care!
Installing a COMETIC MLS (Multi Layer Steel) Head Gasket
The first thing you must do before installing the gasket, check all associated hardware thoroughly for nicks, scratches, or
damaged threads as well as checking all threaded holes. If the hardware is inadequate or damaged, gasket failure may be eminent.
Also chase all the bolts and tap all threaded holes with the appropriate thread chase or cleaning tap. All hardware and mating surfaces
should be free from any old sealers, rust, or carbon.
Check your dowel pins as they register the gasket and head into proper location. Replace worn or damaged dowels. The gasket mating
surfaces must be smooth 50RA or finer. Additional sealer is not required with Cometic MLS Head Gaskets. The outer layers of the
gasket are coated with a .001" thick coating of viton (a high temperature flouroelastomer).
Check brass rivet location to ensure the brass rivet does not interfere with the sealing surface on both the block and head. If the
brass rivet needs to be removed a pair of side cutters will give the best results. Remove only the brass rivet.
Once the gasket is in position double check all passages and overall fitment paying special attention to the bore and chamfer. The
gasket should not fall in the bore or lay on the chamfer in any area. A gasket lying on the chamfer or in the bore will most likely cause a
hot spot and lead to pre-ignition, possibly causing severe engine damage or gasket failure.
"Additional sealer is not required with Cometic MLS Head Gaskets. The outer layers of the gasket are coated with a .001" thick coating of viton (a high temperature flouroelastomer)."
The entire instructions are below if you care!
Installing a COMETIC MLS (Multi Layer Steel) Head Gasket
The first thing you must do before installing the gasket, check all associated hardware thoroughly for nicks, scratches, or
damaged threads as well as checking all threaded holes. If the hardware is inadequate or damaged, gasket failure may be eminent.
Also chase all the bolts and tap all threaded holes with the appropriate thread chase or cleaning tap. All hardware and mating surfaces
should be free from any old sealers, rust, or carbon.
Check your dowel pins as they register the gasket and head into proper location. Replace worn or damaged dowels. The gasket mating
surfaces must be smooth 50RA or finer. Additional sealer is not required with Cometic MLS Head Gaskets. The outer layers of the
gasket are coated with a .001" thick coating of viton (a high temperature flouroelastomer).
Check brass rivet location to ensure the brass rivet does not interfere with the sealing surface on both the block and head. If the
brass rivet needs to be removed a pair of side cutters will give the best results. Remove only the brass rivet.
Once the gasket is in position double check all passages and overall fitment paying special attention to the bore and chamfer. The
gasket should not fall in the bore or lay on the chamfer in any area. A gasket lying on the chamfer or in the bore will most likely cause a
hot spot and lead to pre-ignition, possibly causing severe engine damage or gasket failure.
SevenM: Chill it's not worth getting bent out of shape over!
I recently had a BHG and believe using Permatex Brake quiet was a contributor.
This only became a problem over 30 psi/8000 rpm and I'm guessing there aren't too many 7M's going there.
I recently had a BHG and believe using Permatex Brake quiet was a contributor.
This only became a problem over 30 psi/8000 rpm and I'm guessing there aren't too many 7M's going there.
Besides the finish, the surfaces must be flat. That is checked with a machined straigt edge and a .00" feeler gauge. This is true of the stock headgasket also.
For those that did not refinish, it is because your surfaces are flat.
For those that did not refinish, it is because your surfaces are flat.
3p141592654 said:
Yes notice that its says NOT REQUIRED..... that doesn't mean OMG DONT PUT IT ON THERE CAUSE YOUR GASKET WILL MELT DOWN TO NOTHING AND YUR ENTIRE ENGINE WILL DISAPPEAR!!!
so i used it and everything is PERFECT.
Yes IJ i will not be going that far with the 7M but i will be going that far with the 2J
Why don't you just resurface the head... it's about $50 and the reassurance is well worth it. i didn't think mine was even warped, but i had it done anyway, and the machinist said it was very warped.
fyi- i got a cometic mhg and arp studs and they work great. i torqued to 85 lbs
fyi- i got a cometic mhg and arp studs and they work great. i torqued to 85 lbs
jdub said:There is no MHG that is plug-and-play...proper prep is the key to installing a MHG. The Cometic is a very good MHG, but here are a few things you need to do:
- You check the head for warpage with a machinist straight edge and a set of feeler gauges...0.1mm (0.0039") is the max. The TRSM tells how to do it. A hardness test on the head is highly recommended.
- Both the head and block have to be re-surfaced to the RA spec required for the MHG used. 50 RA max is the spec for a Cometic...you want the lowest RA on both the head and block the machine shop equipment is capable of. (Seven M...you got lucky on your block)
- The proper thickness of the MHG is determined by how much material is removed from the head/block. The stock thickness is 1.0mm...there is .039" per 1.0mm...you can do the math
- You DO NOT want to use any type of spray coating on a new MHG. They come pre-coated with a very thin layer for the initial seal. Cometic specifically warns not to do this. Spray coatings can turn the factory pre-coat into goo. (Seven M...that's twice for you...buy a lottery ticket ASAP) If you re-use a MHG, then using a spray coating is fine...basically you are replacing the factory coating.
- The Cometic MHG uses rivets to hold the MHG together...any rivet that touches the surface of the head must be removed prior to install or you risk a bad seal.
- Using ARP hardware, use the torque spec included in the box...studs vs bolts are different.
- When the block is decked, the front plate has to be machined as well so it doesn't stick up on top. This will prevent a seal as well. Make sure you use RTV per the TRSM on the top of the front plate, otherwise you will have an oil leak.
jdub,
can you give more info on this
- When the block is decked, the front plate has to be machined as well so it doesn't stick up on top. This will prevent a seal as well. Make sure you use RTV per the TRSM on the top of the front plate, otherwise you will have an oil leak.
I just recived my block back from the machine shop but I know I never talked to them about this.......
Seven M said:
Dude...that's not what I said. I said that NEW MHG's come pre-coated and do not require nor recommend a spray sealer....and that using a spray can destroy the factory coating making it useless. Based on what I've seen (and what I've read at every site I've been to on the subject), I said you got lucky...I'm glad it worked for you. However, I would never recommend using a spray sealer on a new MHG...ever. And when you posted on the subject, you made it sound like it was the thing to do. I merely pointed out that your recommendation goes against what the manufacturers recommend.
ismns - that is a great pic (I stole it for the archives
)...that is exactly what I was talking about and it answered jkbmkiii's question perfectly!
resurface just the head? dont you have to do the block too? and when they resurface the head do they have to disassemble it?
well according to the instructions STRAIGHT FROM COMETIC it never says anything about them NOT RECOMMENDING IT. it says not required thats it. so if someone wants to do it then let them. dont tell them that they are wrong for doing it. I put it on there for extra safety. that shit is like super glue.
Seven M said:
Look...you can use spray sealer if you want. What you should not do is make it sound like it's the recommended way to do it...that is just flat wrong. Did you read the MHG link I posted? Here's a quote:
"Another installer error is using a sealer on a coated composition head gasket. "Some sealers will react with the gasket coating and turn it into goo," claims McKnight. "Our philosophy with Victor-Reinz gaskets is if a gasket requires a sealer, we will include it with the gasket. If no sealer comes with the gasket, it doesn’t need any, and no sealer should be used."
Note the words "installer error"
I'm still wondering why you would blow TWO MHGs and believe this is the way to do this. I'm done arguing with you Seven M...
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