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.

 

[viprez586]

Yep, I'm running a MLS HG and my surfaces were shiny smooth. Of course I told my machine shop.

 

[DSMnoobsause]

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.

so youve never seen a MINI running 20+lbs of boost the r53 and r56 can handle way more boost then 20psi and have never had any head gasket failures. also ive never seen 135's or 335's blow any gaskets due to what you are stating
i agree that a stock block and head should be milled for a true surface but his will be just fine.
i think you're more likely to have contaminants on the gasket or head/block surface before you put everything together. if the gasket were to fail.

if you have any questions just look up Alta performance and Mini Madness

 

[vannaksgsx]

Your surfaces were fine to run a MLS. I'm in the same situation- just ordered a OEM MLS. I called Precision Engines, where my head was pampered...AND I called JAM, where I got my Stage 1 block (you can see picks in my blog). Per JAM, it's nearly impossible to get a "mirror" finish on cast iron. You would have been absolutely fine with MLS. Use some copper spray and you're all set.

When in doubt, yea...go with composite- AND listen to Bogus. He has never given me advise directly, but I've seen his posts and people trust him. +1

Vannak

*This is a very good topic. Important and useful.

 

[aspekt9]

Your surfaces were fine to run a MLS. I'm in the same situation- just ordered a OEM MLS. Called Precision Engines, where my head was pampered...AND I called JAM, where I got my Stage 1 block (you can see picks in my blog). Per JAM, it's nearly impossible to get a "mirror" finish on cast iron. You would have been absolutely fine with MLS. Use some copper spray adn you're all set.

When in doubt, yea...go with composite- AND listen to Bogus. He has never given me advise directly, but I've seen his posts and people trust him. +1

Vannak


*This is a very good topic. Important and useful.

I also got all my machine work done at Precision in Dighton. My block and head surfaces looked EXACTLY like that. My MLS sealed fine once I torqued my ARP head studs to what they were supposed to be, I didn't experience any pushing coolant and before my rings shit the bed I had 180 compression across the board. I did however experience some exhaust smell in the oil, not sure if it was the HG or PCV / ventilation setup. Randy at Precision said he uses those surface finishes with plenty of MLS and sprays them with copper and torques them down wet and has yet to have any issues. I trusted him and it worked out.