OEM MLS RA Requirements

[aspekt9]

Does anyone know what the minimum RA is on an OEM MLS head gasket? I just had my entire motor machined and everything is great, but I'm not 100% sure if the deck and head surface are smooth enough for an MLS. I rub my finger down it and I can just BARELY feel mild unsmoothness. Before I left I asked what kind of machine they use to deck heads and blocks and he showed me and said it uses carbide bits and that they're looking to get a CBN machine soon. Here's a picture of it one their website: deck machine. I told them that I was running an MLS head gasket so I don't think they would give it an RA that was not capable of sealing with an MLS, but I don't know how to be sure. Looking at it from above I can see what look like half circles. This is a very reputable shop and they do a lot of 4g63s as well as v8s.

 

[LiquidX]

You'll be fine if it was resurfaced with that machine. Belt sanding would be a no no however.

 

[aspekt9]

You'll be fine if it was resurfaced with that machine. Belt sanding would be a no no however.

Yeah, I know for a fact it was not belt sanded. So even though it doesn't look / feel glass smooth I should be okay?

 

[91gst]

If you have doubts and want to put them to rest then I would get a straight edge and check the level of the block and head with a feeler gauge at multiple locations and make sure that it is still within spec according to the service manual. Here's a post with the procedure. Hope this helps.

http://www.dsmtuners.com/forums/cyl...ock-deck-got-feeler-gauges-straight-edge.html

 

[aspekt9]

If you have doubts and want to put them to rest then I would get a straight edge and check the level of the block and head with a feeler gauge at multiple locations and make sure that it is still within spec according to the service manual. Here's a post with the procedure. Hope this helps.

http://www.dsmtuners.com/forums/cyl...ock-deck-got-feeler-gauges-straight-edge.html

My worry is not whether the surfaces are straight enough, more so whether the surface itself is smooth enough. I've been reading 50 microinches or finer for an MLS. I have no way of checking if both surfaces are that fine.