Is my deck and head surface good to go for OEM Mitsu MLS head gasket?

[packinkimber45]

Hello everyone, I have already asked this on one of my threads, but I figured I would make a separate thread just for this issue so it doesnt get overlooked. I've only gotten one opinion from one member on here and I would like to get more input from everyone. When my machinist decked my block and resurfaced my head he asked me if I was going to run composite hg or mls... unfortunately at the time I was going back and forth which one I wanted to use since I was worried about sealing of mls gaskets. So in that case, my machinist said he did the finish smoothness right in between. He said the ra should be 12-16, but he does not have a tool to gauge it's smoothness. I believe he called a proliferer or something. It's not mirror finish, but not too rough I guess so I could go either way. I dont know if I should run the oem mitsu mls I bought or use a composite one. Looking at the surfaces they are shiny but I see lines that I can feel with my finger nails.
The surfaces are a little dirty from when I picked them up.
Here is the finish on the block

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and the head

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These last two pictures shows the lines I am talking about that I can feel with my finger nails. These same texture and lines are of the same on my block surface.

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Am I okay to run the oem mitsu mls, or should I use oem mitsu composite? I'm going to the dealership asap today before they close for the weekend and I would really like to get lots of input here. Thanks.

 

[BogusSVO]

I posted in your other thread.

But from what I see I would not run the MLS, get a composite either OE or the felpro.

 

[DSMnoobsause]

i think you will be fine ive seen block surfaces alot worse that have and they put mls on them and there fine.

 

[packinkimber45]

I posted in your other thread.

But from what I see I would not run the MLS, get a composite either OE or the felpro.

i think you will be fine ive seen block surfaces alot worse that have and they put mls on them and there fine.

Crap! This is why I have been teetering back and forth. I read both regarding the surface finish. I really wanted to go mls, but now I am getting worried. Might just exchange the mls with composite... I'm torn

 

[agentorange313]

remember the head gasket can change the compression ratio of the piston.

make sure you know what you compression ratio goal is and then find the headgasket that will allow for that compression ratio.

 

[LiquidX]

What are your reasons for wanting to run a ML gasket? The OEM composite gaskets hold fine until about 28psi.

 

[packinkimber45]

remember the head gasket can change the compression ratio of the piston.

make sure you know what you compression ratio goal is and then find the headgasket that will allow for that compression ratio.

This I know. That was one of the reasons why I wanted mls. To bring down my compression ratio. Aacording to the sheet from the machine shop I would be at 8.9 to 1 with the oem mitsu composite. If I went mls it would be lower. I want to run the mls but don't want to deal with sealing issues and have to redo the hg again. This sucks.

 

[agentorange313]

I think that if you stick with 91 octane, 93 if you have it in your area, I know NJ has 93 everywhere, you should be fine. with a 8.9:1 compression ratio.

the evo 7 bolt set up is 8.8:1 stock compression ratio. You should stick with the oe headgasket like liquid said.

question: what level boost are you running (psi)?

oh yea liquid, I started to look up headgaskets after this and couldn't find the oem composite gasket. You have a link for one?

 

[DSMnoobsause]

do you have ARP head studs? if so i think you will be fine

 

[Jerkychew]

I'm going to go ahead and say you would be fine putting in the MLS gasket. Ive machined plenty of these heads and have never had an issue with sealing. The surfaces look good to me.

 

[ramsack]

He said he can feel the machining lines with his fingernail, so no good for a metal headgasket. The surface needs to be perfectly smooth, almost like a mirror!

 

[LiquidX]

oh yea liquid, I started to look up headgaskets after this and couldn't find the oem composite gasket. You have a link for one?

EXTREME PSI : Your #1 Source for In Stock Performance Parts - OEM Composite Head Gasket : Mitsubishi Eclipse 90-99
Mitsubishi OEM Organic Head Gasket (DSM) - Modern Automotive Performance

www.jnztuning.com will have them as well. Just can't get the page to load for OEM parts.

 

[DSMnoobsause]

He said he can feel the machining lines with his fingernail, so no good for a metal headgasket. The surface needs to be perfectly smooth, almost like a mirror!

really? you should see the MINI block and head surfaces then. they use mls and have no issues ever. i had plenty of honda motors with lines in the head and block surface with no issues when i used D16y8 mls gaskets. he will have no issues unless he has some sort of containment on the surface of the gasket.

 

[dsm8883]

really? you should see the MINI block and head surfaces then. they use mls and have no issues ever. i had plenty of honda motors with lines in the head and block surface with no issues when i used D16y8 mls gaskets. he will have no issues unless he has some sort of containment on the surface of the gasket.

None of these engines have the cylinder pressure that a 4g is going to have at 20 pounds of boost and when u get higher in the boost levels is when it starts to push coolant. If u can see marks in the head or deck i would not run a mls headgasket it would be a 50 to 50 shot it will seal good. I also instal mls headgaskets on vw and bmws all the time but they are not built engines or altered.

 

[Rex2342]

I would listen to BogusSVO. He really knows his shit when it comes to this. As was stated already the surface HAS to be a nearly mirror polish for a MLS gasket to seal properly. Also make sure you clean that head surface and block properly before putting anything together. It may look clean but the oils and debris from machining tend to linger. What are your plans for this engine? How much boost you plan on running would easily determine the type of gasket you should use. I'd say for 20-25psi a composite gasket would be fine. I know others have run higher with success but every motor is different. I run 20psi with my Fel Pro gasket all day every day and it's been fine for a few years now. From the looks of that surface and going by the fact that your machinist cannot properly gauge the smoothness of the surfaces I would go composite.

 

[Zex4g63]

The OEM multilayer is not constructed like a Cometic or Felpro MLS. And is pretty damn forgiving as far block surface goes. If it were mine it would be going on.

 

[90tsiawdturbo]

If you don't use the one you just bought I'll probably buy it from ya if ya want

 

[rimmbrme]

I vote should be fine with mls gasket

 

[Red Alert]

I vote you shouldn't listen to a bunch of different people with varying experience on an online forum. Try getting in touch with a shop(try one of the vendors, Darren @ FFWD was extremely helpful when I did mine) who do these things day in a day out. Just because a few people here have had success when they did theirs doesn't mean it will work for you.

 

[Borgratt]

I vote you shouldn't listen to a bunch of different people with varying experience on an online forum. Try getting in touch with a shop(try one of the vendors, Darren @ FFWD was extremely helpful when I did mine) who do these things day in a day out. Just because a few people here have had success when they did theirs doesn't mean it will work for you.

+1 call a shop, don't gamble ### losing isn't something you want to do.

 

[kidtsi]

I posted in your other thread.

But from what I see I would not run the MLS, get a composite either OE or the felpro.

lisen to this guy^^^ the surface is not that good to use and mls head gasket.

 

[ramsack]

BogusSVO is a machinist, he is not some random board person chiming in, he is giving a professional recommendation.

 

[Red Alert]

BogusSVO is a machinist, he is not some random board person chiming in, he is giving a professional recommendation.

And the machinist he had do the work said that finish is ~12-16, which if he is able to grab anything with his nail it clearly isn't near that smooth since that would be like the surface of a magazine or a plastic spoon. I'm not saying Bogus is wrong, but what I'm getting at is he should call up a trusted shop for information on these sort of things instead of a forum where he's going to get 20 different answers from 20 different people. When it comes to motors I only talk to 2 different people, I don't come onto a forum asking advice from other people like myself...

 

[Zex4g63]

BogusSVO is a machinist, he is not some random board person chiming in, he is giving a professional recommendation.

*reads my profile*

 

[packinkimber45]

Already returned the multi layer yesterday. I will be running the oe composite. I dont want to chance not getting a good seal. Thanks to all that replied. Bogusvo... thank you. You are always providing answers for me on my pms and on my threads as well. Again thanks everyone.