memmi

I suspect the motor may have popped, see here for a description:

https://www.rx7club.com/showthread.p...hreadid=248301

So I performed a compression test by removing and checking the pressure at each lower plug, one at a time.

Here's where I'm stuck... upon turning over the car the pressure tester reads 0, nothing, on both front and rear rotor. I tried 2 compression testers to verify that the tester was not the issue. I removed the tester and can feel pressure escaping the chamber.

So I can only see 2 possible explainations:

1. I blew every apex seal that the little engine contained.

2. I am a complete moron and am doing something wrong in the process.

Given that I've never heard of the primary option and I should still see some compression even under this secnario... I'm unfortunatley leaning towards the latter option.

Any suggestions to save me from subscribing to the latter option?

911GT2

Well technically you'd only need to blow 2 apex seals on each rotor to have no compression. Each chamber needs 2 seals to hold compression, so if any 2 were gone, you'd have no compression.

memmi

Right, I'd thought that would still be just as unlikley and I should still see some compression reading on the meter, no?

paw140

Just because you feel air escaping from the spark plug hole doesn't mean that you have much compression. You are probably doing the test right, and have just broken a bunch of apex seals. It's pretty hard to screw up a compression test. You just thread the thing in and go.

93BlackFD

unless he bought a vaccum/pressure test kit instead of a compression test kit

also be sure to remove the check valve with a valve stem tool

Trexthe3rd

When you say turn over, how long did you keep it cranking? Because, to do it right you need two people for this (unless you have a really long hose for the tester)
You'll need a compression tester with a hold function.
After setting up the tester (screw into plug hole), with the hold function on crank the engine for a couple of seconds. The reading should show you your max compression.
Step two, turn off the hold function(or keep your finger on the pressure release button for the mechanical ones). Have someone crank the engine for about 10 sec. Keep your eye on the gauge. You should see the needle fluctuate from 0 to close to your max reading. If you have a bad seal, some of the fluctuation will not reach near the max reading.

Sprockett

Well, unfortunately, either way you will more than likely need to rebuild it. So why not just get it out and look? I know that sounds overly simplified, but I think you get what I mean)

memmi

yea, everything i'm doing is consistent with the suggestions here (except I've only been cranking for 3-5 seconds, not a full 10). I just cant imagine that I'da killed compression on both rotors!

89Turbo944

Dont crank for 10 sec. Cronk for 4-5 full rotations fo the rotor.

Also check that the check valves in the compression testers arent blocked open. Because if they are then you will read 0 psi. Also if they arent threaded in properly. Leaky fitting. Check the compression tester over very well and try again. And pray to the rotary gods that the engine is ok.