1988 RX7 Compression
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1988 RX7 Compression
Good day to all.
i have a 1988 Rx7 and I recently checked the compression. Here is what I got:
T1-70 T2-90
L1-70. L2-90
Question…do these numbers warrant a rebuild NOW - or can a drive a bit and do it later? Car cranks, starts and runs fine.
i have a 1988 Rx7 and I recently checked the compression. Here is what I got:
T1-70 T2-90
L1-70. L2-90
Question…do these numbers warrant a rebuild NOW - or can a drive a bit and do it later? Car cranks, starts and runs fine.
Your compression results do not make sense. Did you use a rotary specific tester, or are you using a piston compressor?
The location where you take the reading is irrelevant (leading or trailing). They should and do show the same results as expected.
What you should be getting is three distinct compression readings per rotor, as there are 3 sealing chambers on each that you are testing.
Your results should look something like this as an example:
Rotor 1 - 92, 90,87
Rotor 2 - 96, 90, 94
If you're using a piston compression tester you'll want to remove the pressure valve and watch for the three distinct pulses and record them as best you can.
What your limited test does show is that rotor one looks more tired than the rear rotor. However, if your car still starts and runs fine, then a preemptive rebuild is just that, preemptive. I would say it's not entirely needed unless you start having issues with starting. Rebuilds cost a lot more than they used to because of part availability if you need to replace something like housings.
The location where you take the reading is irrelevant (leading or trailing). They should and do show the same results as expected.
What you should be getting is three distinct compression readings per rotor, as there are 3 sealing chambers on each that you are testing.
Your results should look something like this as an example:
Rotor 1 - 92, 90,87
Rotor 2 - 96, 90, 94
If you're using a piston compression tester you'll want to remove the pressure valve and watch for the three distinct pulses and record them as best you can.
What your limited test does show is that rotor one looks more tired than the rear rotor. However, if your car still starts and runs fine, then a preemptive rebuild is just that, preemptive. I would say it's not entirely needed unless you start having issues with starting. Rebuilds cost a lot more than they used to because of part availability if you need to replace something like housings.
after you do a proper compression test, so long as those numbers are real +/- then you can drive that car all day everyday. do the test hot and cold though. 70s is really when you should start planning to take it apart. defer the rebuild for as long as it drives. one day you will turn it off and it just wont ever start again.
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[QUOTE=Slofton;12639807]Thank you for the reply.
Yes, I was using a piston compressor tester.
/QUOTE]
these are ok to use but need to remove the schrader valve so you can see the compression pulses of each rotor face.
Yes, I was using a piston compressor tester.
/QUOTE]
these are ok to use but need to remove the schrader valve so you can see the compression pulses of each rotor face.