Head warp tolerance.

[02V70]

I have a straight edge and feelers coming in the mail. How flat does the head need to be? Also, do some gaskets allow for more warpage than others? A fiber composite victor reinz gasket says .03mm for the short side and 0.05 mm for the long side. Some other gaskets I found says it is coated in Viton, elastomer, or silicone. How much better would they be for warp tolerance? Would an MLS gasket require a flatter surface? A fiber composite gasket and MLS are not the same right?

Here is a photo of my gasket options

Screenshot 2022-01-11 210224.jpg (97.71 KiB) Viewed 2209 times

[abscate]

Per Volvo in units of millimeters

Maximum machining allowed 0.30mm

Maximum displacement from front to rear 0.50mm

Maximum displacement side to side 0.20mm

With 20 hours on a proper head job, it’s insanity not o use an OE Volvo head gasket

[vtl]

MLS is multi-layer steel. MLS requires better finish, but seals better. Cracked MLS means a total self-destruction of the engine. Something went so wrong that even MLS cracked/burnt.

The factory finish on the Volvo cylinder heads is not very smooth. You can definitely do better even with DIY polishing.

Also you have to use the same kind of head gasket that was in the engine originally. Agree with abscate you better stick with the original gasket. On the other hand, OE gasket may last you, say, ten times you'll be owning that car. While Victor Reinz will last only twice less than OE, which is still longer that you may need.

[02V70]

I probably won't be owning the car that long as it has 250k miles. As for the better finish that MLS requires, can this be achieved with the DIY head resurfacing you talked about? Would it need a flatter glass to stick the sandpaper too? Is the Volvo OE one MLS? As for MLS sealing better, would that mean I have a better chance if my block is slightly warped?

[vtl]

Volvo switched to MLS type of gasket somewhere around 2003 (?). You have to use the same kind of gasket you've found in your engine, they are not interchangeable.

DIY head polishing is good enough for any kind of gaskets, MLS including. In fact, it is smoother than the factory milled surface.

[02V70]

A different user said to use 600 grit sandpaper for MLS gaskets. I would use this one after I go through the rougher sandpaper right?

[vtl]

Right.

[02V70]

I am going to cut the bad gasket to tell if it is MLS. Am I correct that if it has metal inside, it is MLS, and if not, it is not MLS? Would some gaskets be single layer steel?

[02V70]

I just cut open my gasket, and it looks only that there is a single layer of steel.

[02V70]

So if my gasket has one layer of steel, does that mean it is not MLS, or are the multiple layers hard to see? I can post a picture if that helps.