How to check a head for warp
 

How to check a head for warp.

The first thing to do is remove all carbon and old gasket material.

Then with a machinist straight edge, Check all 8 positions.
If .003 can be fit under the straight edge, the head needs to be resurfaced.
Also Note the fire ring grooves from the head gasket, if the head has these, and checks flat. The head needs to be resurfaced.


First position.
https://www.miataturbo.net/attachmen...ine=1333032655

Links to the other 7 positions.
http://i261.photobucket.com/albums/i...o/DSCF3976.jpg
http://i261.photobucket.com/albums/i...o/DSCF3974.jpg
http://i261.photobucket.com/albums/i...o/DSCF3977.jpg
http://i261.photobucket.com/albums/i...o/DSCF3978.jpg
http://i261.photobucket.com/albums/i...o/DSCF3980.jpg
http://i261.photobucket.com/albums/i...o/DSCF3979.jpg
http://i261.photobucket.com/albums/i...o/DSCF3981.jpg

I love machine-shop porn.

We check the same way, but .003" with an MLS gasket would make me nervous. I would want to see .0015", preferably less.

.003 is for a composite gasket.

For a MLS .0015 would be on the wide side. Since I do not get to check the block most of the time.

If I know the head takes a MLS, it is about automatic to surface it, if I have seen wher a rol-loc has been used, or any sort of fire ring imprinting.

Our head guy does the same - surfaces every head no matter what. The factory HG on the 1.8 is MLS so it's critical.

Luckily the blocks are very stout - I've yet to come across a warped BP block.