Spraying GM Performance MLS Gasket
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Teching In
Joined: Feb 2014
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From: Richardson, TX
Spraying GM Performance MLS Gasket Hi everyone,
I’ve read multiple post on spraying copper during head gasket installation and have a question about the procedure. If I choose to spray the new head gaskets, do I spray the entire front and back to include the rubber that is around the perimeter etc? Thanks for any responses in advance.
I’ve read multiple post on spraying copper during head gasket installation and have a question about the procedure. If I choose to spray the new head gaskets, do I spray the entire front and back to include the rubber that is around the perimeter etc? Thanks for any responses in advance.
MLS gaskets already have a sealant on them and can be install dry and many will say that's what's recommended . I've done it both ways with success so its okay to spray a light coat on each side prior to installation. You should still be able to see what the gasket looks like after spraying a light coat so if your going to spray them just don't over spray them.
Thread Starter
Teching In
Joined: Feb 2014
Posts: 49
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From: Richardson, TX
Trust me I’ve been torn between spray vs no spray. This is my second go around with head gaskets. First time I did a HCI swap with the motor in the car. It’s not easy with minimal space on a 02 Camaro. I originally used ARP studs and must have muffed the install. This time I pulled the motor and picked up GM Performance Gaskets. I was worried about getting the copper on the rubber surrounding the coolant passages. Do I spray the copper and let it sit for a few (get tacky) prior to putting the heads on or let it fully dry?
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From: Thibodaux LA
MLS gaskets don't need to be sprayed. They have viton rubber on all the sealing surfaces. The more important thing is to make sure both mating surfaces are super clean/dry and straight. I work for Honda. They used MLS gaskets for over 20 years. We never used copper spray. Just use the GM .051 think gaskets. They are very forgiving. Iv been doing research on this because I'll be doing heads and cam soon as well. Just make sure you prep the surface very well.
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Verdad Gallardo I'll be sure to post on here warning others not to spray them if and when I ever run into an issue with spraying them. Like I said I've done it both ways with success and I'll continue to take the advice of professionals who do this for a living.
I’ve sprayed MLS gaskets without issue. I do it because I’ve MLS gasket failure without spraying. I’m not saying I’m right and you should spray them. But it works for me...so far anyway.
The question I have is...and we’ve talked about this before on Tech and gotten nowhere...has anyone ever had a MLS headgasket fail because it was sprayed?
The question I have is...and we’ve talked about this before on Tech and gotten nowhere...has anyone ever had a MLS headgasket fail because it was sprayed?
I’ve sprayed MLS gaskets without issue. I do it because I’ve MLS gasket failure without spraying. I’m not saying I’m right and you should spray them. But it works for me...so far anyway.
The question I have is...and we’ve talked about this before on Tech and gotten nowhere...has anyone ever had a MLS headgasket fail because it was sprayed?
The question I have is...and we’ve talked about this before on Tech and gotten nowhere...has anyone ever had a MLS headgasket fail because it was sprayed?
That's the test we need to be able to prove what's best.
I got a 5 dollar bill that says it wouldn't have mattered. I venture to guess that 99.9% of the failures were in such a manner that spray wouldn't have changed a thing. It's just a sticky coating, what can it really do?
When I think on this subject I always think to myself that there are tens/hundreds? of thousands of LS motors that have been built in the last 20 years, all of them survived their standard duties without the spray. All of the performance builds I have been around did as well. And all the repairs I have done have held. And if they hold together with the spray and without, how will we ever know what's better.
Then going down the bunny trail further you think of the millions of engines out there that don't have copper spray on their headgaskets that out last the car they came in, and really start wondering..
Last edited by 00pooterSS; Apr 7, 2020 at 08:33 PM.
The biggest issue/question is, would that exact engine in that exact scenario that exact same moment (everything being the exact same) have held if it had had the spray on the gaskets.
That's the test we need to be able to prove what's best.
I got a 5 dollar bill that says it wouldn't have mattered. I venture to guess that 99.9% of the failures were in such a manner that spray wouldn't have changed a thing. It's just a sticky coating, what can it really do?
When I think on this subject I always think to myself that there are tens/hundreds? of thousands of LS motors that have been built in the last 20 years, all of them survived their standard duties without the spray. All of the performance builds I have been around did as well. And all the repairs I have done have held. And if they hold together with the spray and without, how will we ever know what's better.
Then going down the bunny trail further you think of the millions of engines out there that don't have copper spray on their headgaskets that out last the car they came in, and really start wondering..
That's the test we need to be able to prove what's best.
I got a 5 dollar bill that says it wouldn't have mattered. I venture to guess that 99.9% of the failures were in such a manner that spray wouldn't have changed a thing. It's just a sticky coating, what can it really do?
When I think on this subject I always think to myself that there are tens/hundreds? of thousands of LS motors that have been built in the last 20 years, all of them survived their standard duties without the spray. All of the performance builds I have been around did as well. And all the repairs I have done have held. And if they hold together with the spray and without, how will we ever know what's better.
Then going down the bunny trail further you think of the millions of engines out there that don't have copper spray on their headgaskets that out last the car they came in, and really start wondering..
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We use Hylomar spray on our mls head gaskets. Works way better than the copper coat. On a stock or basically stock engine there is no need to spray, but when you get into high compression or boost applications you tend to have some coolant seepage out of the mls head gaskets. So its better to spray it. Better safe than sorry.
This is how i look at it. Does the manufacturer say to spray them? No. Does the factory mls gaskets on ANY car come sprayed? No? So why would you even consider it? Never sprayed, never a problem. Now used gaskets, thats a different story. I work at a dealership, I've seen leakages from the Techs spraying new gaskets. I have not seen one leak without spray, however.
But dont get all nervous, chances are if the block and heads are flat, you wont have a problem if you sprayed them. Its just not needed and the manufacturer doesnt recommend doing it....but I've never seen a gasket say not to do it either.
But dont get all nervous, chances are if the block and heads are flat, you wont have a problem if you sprayed them. Its just not needed and the manufacturer doesnt recommend doing it....but I've never seen a gasket say not to do it either.
I agree with you. My experience is with big bore engines. Not a lot of area between cylinders. Big compression engines. Some engines were blown big block off shore race stuff. We found the spray to help seal the headgaskets. Trial and error. We were a big shop that did a metric ton of R&D for big money teams. Honestly probably doesn’t do didley for the average mild LS build. But again my question remains...does it actually hurt anything? My Cometics for my 434 said right on the box do not use gasket spray. Who colors between the lines anyway? I sprayed them. Both times I assembled the engine. But in fairness it’s 12.42:1, but that is mild compared to a lot of race stuff I have been involved with.
I was picturing standard issue LS stuff and other too close to stock type of stuff.
And like TTur said I could see it helping seal a very minor coolant seep.
But you open up the gap very much at all and nothing is gonna save ya lol. I feel that most scenarios out there are going to be a it's not gonna leak either way, or a whoopsie happened and spray or no spray aint gonna matter.
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Not sure if you guys know anything about Hylomar spray. It is what they use to put turbine engines together. It is designed to act like a combo lubricant/sealer. When you use aluminum heads on an iron block during the heat cycle the heads actually move around during high boost. The Hylomar spray lets them do so and keeps the water passages sealed as well as the cylinders. When you torque down the head gaskets initially it lets the gaskets move naturally as they crush so they don't have a chance of binding anywhere at all. Because of this there is no added thickness to the head gaskets like you get from cooper coat or other sealers. There really is no comparison. When we started spraying north of 500 we noticed a little seepage on some of the water passages when we did the off season refresh. With the Hylomar spray we no longer have that problem. It can handle whatever heat your engine can produce.
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These aren't turbine engines.
These engines can go 400,000 miles on the original non sprayed gasket. I've seen it.
You don't need to spray an ls engine head gasket unless you're building junk that should be resurfaced.
These engines can go 400,000 miles on the original non sprayed gasket. I've seen it.
You don't need to spray an ls engine head gasket unless you're building junk that should be resurfaced.
Not sure if you guys know anything about Hylomar spray. It is what they use to put turbine engines together. It is designed to act like a combo lubricant/sealer. When you use aluminum heads on an iron block during the heat cycle the heads actually move around during high boost. The Hylomar spray lets them do so and keeps the water passages sealed as well as the cylinders. When you torque down the head gaskets initially it lets the gaskets move naturally as they crush so they don't have a chance of binding anywhere at all. Because of this there is no added thickness to the head gaskets like you get from cooper coat or other sealers. There really is no comparison. When we started spraying north of 500 we noticed a little seepage on some of the water passages when we did the off season refresh. With the Hylomar spray we no longer have that problem. It can handle whatever heat your engine can produce.
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Hylomar is probably what I should have used then, I just wanted it to help make cleanup a little easier if I removed the graphite gasket sometime in the future, not really for increased sealing as it's not intended for graphite gaskets.