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cometic head gaskets #3207755
01/24/24 11:06 AM
01/24/24 11:06 AM
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BigFish69 Offline OP
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SBM do you spray coat mls cometic head gaskets ? if so what are you spraying them with, also what are you torquing them to with head studs.
thanks Tom

Re: cometic head gaskets [Re: BigFish69] #3207780
01/24/24 12:41 PM
01/24/24 12:41 PM
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AndyF Offline
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No, put them on dry in most cases. There are a few engines where sometimes you might need some RTV around certain water holes but that is rare.

Re: cometic head gaskets [Re: AndyF] #3207790
01/24/24 01:17 PM
01/24/24 01:17 PM
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dvw Offline
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I put them on dry unless They're being reussed. Then I spray with copper coat.. Torque to 85lb/ft with ARP lube.
Doug

Last edited by dvw; 03/20/24 06:37 PM.
Re: cometic head gaskets [Re: dvw] #3207798
01/24/24 01:29 PM
01/24/24 01:29 PM
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6PKRTSE Offline
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Originally Posted by dvw
I put them on dry unless They're being reussed. Then I spray with copper cote.. I torque to 85lb/ft with ARP lube.
Doug


Same here. Dry when new, copper coat spray when re-using.


1963 Belvedere 440 Max Wedge Tribute
1970 Charger R/T S.E. 440 Six Pack
1970 Challenger R/T, 528 Hemi
1970 Charger 500 S.E. 440 4 BBL
1970 Plymouth Road Runner 383
1974 Chrysler New Yorker 440
1996 2500 RAM 488 V-10 4X4
2004 3500 Dually Cummins 4x4
2012 Challenger R/T Classic.
Re: cometic head gaskets [Re: 6PKRTSE] #3207800
01/24/24 01:32 PM
01/24/24 01:32 PM
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On the parachute mount
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n20mstr Offline
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SBM , last one i did, small amount of orange/red hi temp rtv around the water ports. other than that...DRY


....BAD A$$ STREET CAR.....
Re: cometic head gaskets [Re: n20mstr] #3207803
01/24/24 01:37 PM
01/24/24 01:37 PM
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GY3 Offline
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Always dry.


'63 Dodge 330
11.19 @ 121 mph
Pump gas, n/a, through the mufflers on street tires with 3.54's. 3,600 lbs.
10.01 @ 133mph with a 250 shot of nitrous an a splash of race gas. 1.36 60 ft. 3,700 lbs.

Re: cometic head gaskets [Re: GY3] #3207862
01/24/24 04:53 PM
01/24/24 04:53 PM
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Marion, South Carolina [><]
an8sec70cuda Offline
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I always spray them w/ coppercoat. Never had an issue.


CHIP
'70 hemicuda, 575" Hemi, 727, Dana 60
'69 road runner, 440-6, 18 spline 4 speed, Dana 60
'71 Demon, 340, low gear 904, 8.75
'73 Chrysler New Yorker, 440, 727, 8.75
'90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt
'06 GMC 2500HD LBZ Duramax
Re: cometic head gaskets [Re: an8sec70cuda] #3208034
01/25/24 08:54 AM
01/25/24 08:54 AM
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blowndart Offline
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Originally Posted by an8sec70cuda
I always spray them w/ coppercoat. Never had an issue.

Same

Re: cometic head gaskets [Re: blowndart] #3208035
01/25/24 08:59 AM
01/25/24 08:59 AM
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pittsburghracer Online work
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Cometic Multi-Layer Steel (MLS) head gaskets go on dry because they are coated with a sealant. Each MLS head gasket is coated with a . 001" thick Viton rubber that is bonded to the outer stainless steel layers. Adding an additional sealer can hinder the performance of an MLS head gasket.


1970 Duster
Edelbrock headed 408
5.984@112.52
422 Indy headed small block
5.982@112.56 mph
9.42@138.27

Livin and lovin life one day at a time




Re: cometic head gaskets [Re: pittsburghracer] #3208049
01/25/24 10:49 AM
01/25/24 10:49 AM
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an8sec70cuda Offline
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I've talked to different builders and it seems to be 50/50 on spraying them versus not. Dan Costello (DRAM here, RIP) at Performance Only recommended I spray them, so I did. Never had an issue since 2006. Even after hurting some pistons w/ nitrous, I've never hurt a head gasket. Can't be too detrimental to their performance.
The hemi head gasket gets REAL thin near the pushrod on a big bore too.


CHIP
'70 hemicuda, 575" Hemi, 727, Dana 60
'69 road runner, 440-6, 18 spline 4 speed, Dana 60
'71 Demon, 340, low gear 904, 8.75
'73 Chrysler New Yorker, 440, 727, 8.75
'90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt
'06 GMC 2500HD LBZ Duramax
Re: cometic head gaskets [Re: BigFish69] #3208057
01/25/24 11:26 AM
01/25/24 11:26 AM
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jwb123 Offline
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as what others said dry when new spray with copper coat when reusing. One thing I want to mention is that if you are putting cometic style gaskets on an older engine the surface finish of the block and heads are critical to getting them to seal the best. Cometic gaskets are layers of stainless steel wich is very hard and durable, but they don't conform for any irregularities. The stock surface finish of all older muscle car engines is too rough.

file:///C:/Users/Hp280G/Downloads/FPTB-108-Surface-Finish.pdf

Re: cometic head gaskets [Re: jwb123] #3208063
01/25/24 12:11 PM
01/25/24 12:11 PM
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dvw Offline
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I've reused them as many as 3 times at 15-1. 100's of passes with no issues. The only reason that they get sprayed is that some of that runbber coating gets a little shreaded.
Doug

Re: cometic head gaskets [Re: dvw] #3208069
01/25/24 12:34 PM
01/25/24 12:34 PM
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moparacer Offline
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I copper coat them when new. And when I reuse them, I drill the rivets out, and clean and spray both sides of the thin pieces that have the coating on them.


67 Barracuda street/bracket car 11.27-119
68 Dart 502 BB 8.70s-152
414 cid SB Dragster 7.65-174
Re: cometic head gaskets [Re: moparacer] #3208113
01/25/24 03:11 PM
01/25/24 03:11 PM
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n20mstr Offline
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Oh i forgot i do spray mine......with lots of NITROUS

grin


....BAD A$$ STREET CAR.....
Re: cometic head gaskets [Re: n20mstr] #3208159
01/25/24 07:58 PM
01/25/24 07:58 PM
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BigFish69 Offline OP
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Thanks for the reply seems both ways work for everyone. also this one will see its fair share of nitrous.

Last edited by BigFish69; 01/25/24 08:09 PM.
Re: cometic head gaskets [Re: BigFish69] #3208248
01/26/24 10:19 AM
01/26/24 10:19 AM
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Brad_Haak Offline
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The Mr. Gasket MLS gaskets I put on dry before the last dyno session showed indications of fluid seepage, even though they are coated and supposed to not need anything else. When I put the heads back on, I switched to Cometics and used the Mopar spray-on sealer the dealers used when replacing all the blown-out Dodge Neon head gaskets with MLS years ago. The heads' gasket surface are definitely smooth enough for MLS, but the block deck may not be and I didn't want to take another chance with leaks.


2021 Challenger 6.4L Scat Pack 1320
100% stock: 1.680, 11.894 at 113.75 (DA 175 ft)
weight reduction, wheels, tires, Hellcat air box: 1.661, 11.686 at 115.97 (DA 710 ft)

1973 Challenger 452 ci street/strip [2008]
pump gas, DOT radials: 1.454, 10.523 at 126.44 (DA 514 ft)
Re: cometic head gaskets [Re: Brad_Haak] #3208254
01/26/24 10:43 AM
01/26/24 10:43 AM
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HardcoreB Offline
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Originally Posted by Brad_Haak
The Mr. Gasket MLS gaskets I put on dry before the last dyno session showed indications of fluid seepage, even though they are coated and supposed to not need anything else. When I put the heads back on, I switched to Cometics and used the Mopar spray-on sealer the dealers used when replacing all the blown-out Dodge Neon head gaskets with MLS years ago. The heads' gasket surface are definitely smooth enough for MLS, but the block deck may not be and I didn't want to take another chance with leaks.
I remember reading this with yours and maybe a couple others using that Mr, Gasket headgasket. I play with headgasket assemblies very often and have evolved my 'process' to use small films of easily displaceable sealers around water. Permatex pipe-dough etc. I have used that same 'failure-prone' gasket a few times and have had 100% success. IIRC the Mr. Gasket one lacks raised beads around some cooling areas? But again, use what you are comfortable with! I wasn't going to chime-in because I knew there'd be many techniques and obviously they'll vary with what I do out of respect for abilities. One of the main reasons for me is like DVW has mentioned is typically you get that sealing film delaminating in areas so when you start stacking up overlapping 'hanging chads' you'll get a recipe for a leak. I have never thrown out a MLS gasket, always reusing them. Respectfully, Sean

Re: cometic head gaskets [Re: HardcoreB] #3208264
01/26/24 11:25 AM
01/26/24 11:25 AM
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Brad_Haak Offline
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I'd have reused the Mr. G's with the same spray coating, except I figured out I needed to use the 4.50" instead of 4.41" while it was torn down. The price difference was moot at the time, so I decided to give the Cometics a try. Still have the Mr. G's hanging on the wall in my garage, FWIW.


2021 Challenger 6.4L Scat Pack 1320
100% stock: 1.680, 11.894 at 113.75 (DA 175 ft)
weight reduction, wheels, tires, Hellcat air box: 1.661, 11.686 at 115.97 (DA 710 ft)

1973 Challenger 452 ci street/strip [2008]
pump gas, DOT radials: 1.454, 10.523 at 126.44 (DA 514 ft)
Re: cometic head gaskets [Re: Brad_Haak] #3221626
03/20/24 10:24 AM
03/20/24 10:24 AM
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Always did dry, last time I sprayed them with copper coat and got a very small amount of water in a cylinder. Went back to dry and no issues so far. I don’t reuse them. I know you can, but I’m lazy and hate doing things twice. Oh, watch out that the center rivet doesn’t get pinched between the block and head it you are using stock castings.

Last edited by FurryStump; 03/20/24 10:25 AM.

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Re: cometic head gaskets [Re: dvw] #3221841
03/21/24 08:26 AM
03/21/24 08:26 AM
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Minn
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SportF Offline
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I appreciate that info.
Originally Posted by dvw
I've reused them as many as 3 times at 15-1. 100's of passes with no issues. The only reason that they get sprayed is that some of that runbber coating gets a little shreaded.
Doug







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