Hello! I am currently in the process of rebuilding the engine in my 1990 NA, and it looks like the grooves from the side seals and oil seals are within spec.
EDIT: Sorry I was wasn't clear, I am talking about my front and rear iron housings.
However, when I put a straight edge on the housing, a .0015" feeler gauge and move freely under the parallel near the tips of the "footaball" shape.

My first question is, can lapping fix this? Is it normal that the part of the face inside the combustion chamber is "lower" than the rest of the housing outside of it?

My second question is about the durability of a lapped housing. I am putting all new seals and bearings and new rotor housings into my engine and hence I am hoping to get a fair bit of mileage out of it (100K miles). Do you think that a lapped housing will last this long? I have heard that lapping removes the nitride coating and makes them wear faster....

Thanks,
Andrew

 

Andrew, if you have new rotor housings etc you probably should go ahead and spend the extra amount. You can't remove more than 0.002" so they should be as good as new and last as long. If you do lap them, you will need a thicker spacer ring up front which you can get at a reasonable price at mazdatrix.