Oops, I forgot to adjust for the atmospheric pressure when I did my estimated conversion. It should have read 4.5:1 for #2 and 7.5:1 for the rest. 4.5:1 = 4.5 atmospheres, 1 atmosphere= 14.696 psi. So 80psi minus atmospheric pressure,divided by14.696 = 4.44:1. I don't even know if you can convert like that, but every motor that I've seen specs for worked out like that. My motor is rated at 8.5:1 and 140 psi when checking compression by the book (this works with my conversion).
Either way my readings in psi were; #2 was about 80 psi and the others were around 125 psi without adding oil. After adding oil and retesting they all went up a bit (#2 to 90 psi others to 130-140 psi) so I know the rings are worn. But #2 must have other causes for leakage too (a bad valve)?.
I've already exhausted myself working on the ignition (timing, plugs wires, ig module, distributor etc), The cam lobe lift was within specs but I don't know about the valve timing.
I figured that if I fix the compression issue I could possibly eliminate some of my problems. My so called leakdown was nothing more than guessing at this point, that's why I'm on here asking questions. I'm no expert on internal engine problems like this. My main goal is to get the compression balanced out, I don't want to do a full rebuild really.
89 s-15, 89 xr7 (sc powered
), 95 park ave, 98 24v taurus.
Last edited by jwxr7 : 02-03-2005 at 09:02 PM.
Reason: messed up