1994 Mazda Miata Engine Rebuild – Part 2
- March 29th, 2013
- By Martin Iwanowicz
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Well, in my previous post I wrote about some interesting cylinder marks on the #2 and #3 cylinders. Today I measured the head and found .033″ runout on the plane. I was so surprised, I literally measured it 9 times. The tolerance is .004″
After accepting that it was badly warped, I decided to do a more thorough inspection, and quickly found these little treats on the #2 and #3 cylinders:
#2 head crack
#3 head crack
So that explains it. #3 had the worse looking cylinder, and also the bigger crack.
For what it’s worth, I was never expecting to find this in my engine. The car burned oil, but it’s well documented that these engines seize their oil control rings. It never used any coolant as long as I’ve had it, and thought I was just going in for some routine (every ~150,000mi) maintenance.
Boy was I wrong.
Well, I guess I’m in the market for a new head, and seriously considering getting some more extensive work on the bottom end. I was content with just deglazing the cylinders, but now I know that the engine has had some bigger issues in the past (probably overheating) and it makes me much more suspect about the bottom end.
