I took it on it's final drive...My MS3 motor has finally bit the dust.
ROD knock... 283,010 miles.
Such a shame, I was really hoping to get it and the original clutch over 300k. The rest of the car is still in excellent condition.
Finally did a compression test on the MS3- only because I was doing one on the Miata and thought I should go ahead and get it over with so I actually know rather than assume. The numbers weren't terribly awful, better than I was expecting, honestly.
Cylinder 1- 155/165
Cylinder 2- 150/175
Cylinder 3- 150/162
Cylinder 4- 150/178
I expected to see at least one, if not two, below minimum spec. This puts me at about ~19% down on each cylinder from healthy spec.
I'm almost done with the Miata and if I can get it running and driving dependably, I'll use it as a daily so that a rebuild can be done on the MS3.
If it is not too late, try a leak-down test. Compression tests are subject to all sorts of variation: was the throttle open? Is the starter good? What was the battery SOC? Were the other spark plugs out? Is the o-ring on the gage good? And at the end of the day you still have no idea where the engine is leaking from. I hate it.
A leak-down test is subject to fewer variables and will identify where any leakage is coming from.