Compression Checking on a Small Block Miata

[POS Racing]

I just did a compression check on my 93 with 104K on it.

1=182
2=191
3=163
4=190

I did the test COLD, and I dunno what difference it's gonna make.... Do you folks think the numbers would change drastically?

Now obviously, I'm a bit worried by #3, and I'm gonna guess it's a valve because the plugs look identical across the board. I never bothered to do the oil in the cylinder trick.

Did you depress the accelerator when you tested, it made quite a difference on my car? That 163 psi reading seems off I wonder why the 19 psi difference? I'd like to see the results from a wet test to see if it is s valve or rings, that would help answer the question on why its lower.

[OUTRACE]

The tests were done at WOT. Looking at the plugs, I'm assuming that the low cylinder is due to a valve not seating correctly. If the rings were that bad, I'd have some soot around the plug face.