I'm not convinced by the carbon argument. Your cold 99 engine with 135K also has much higher compression than the 100K D16Z6. Just seems curious, though the leak down numbers are good for the D16Z6.

 

Yeah the compression tests don't really make sense to me either. The '99 Civic showed higher numbers than my '95 Civic. Also the numbers comparing both cars for hot/cold compression test are all different, even though I did the tests the exact same way on both cars.

I've just read that higher compression numbers can be caused by carbon buildup.

At this point, the leak down test's I've done for the motors seem to make more sense than the compression tests. I have yet to do a leak down test on my '99 but that should also provide more definitive answers.

Regardless, I'm getting the "new" motor sometime the middle of this week. Hopefully I can do the swap soon and get things running..

 

Good luck with the purchase.

On a separate note, I'm looking for an SRS unit for my 97 Civic DX sedan. If you know where I can find one, please PM me.