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-   -   Compression readings and smoke (https://www.rx7club.com/general-rotary-tech-support-11/compression-readings-smoke-100979/)

JamesC 07-30-02 11:44 AM

Compression readings and smoke
 
I'm about to buy an RX7 in the UK, subject to a compression test.

I've not done a compression test before. Do you take out one plug at a time, remove fuel pump fuse and spin on the starter, or turn by hand?

What readings should I look for?

THe car smokes for a second or two when started from cold. Is that normal for rotaries?

Also, the exhaust smells quite fumey on idle. Is that normal?

The car pulled smoothly from low revs, but had less torque than most cars (but lots of power) is that normal?

It's a 2nd Gen N/A

Any help most appreciated - thanks!!!

JamesC 07-31-02 02:12 PM

Can anyone help with this, or am I worrying about things I needn't?

Cheers

Damnfuct 08-01-02 08:29 PM

Re: Compression readings and smoke
 
if the smoke is white, that's coolant.. if it's blue or greyish, that's oil. Considering rotaries burn oil, might or might not be normal. Compression numbers should be as high as possible.. i did a cmop test on some ol TII that i never bought.. it was like 69 69 69 and 71 71 71, that equates to about 5:1 compression, nevertheless, i still didn't buy the car (don't know if that's normal or means it's just old). Been in a friend's 2nd gen NA and it smells like gas most of the time (gas smells good), and i believe a compression test is done by cranking the engine over.. normal compression testers do not work because it only shows teh highest reading.. since rotaries have 3 faces you need to somehow make the needle return to 0.. search the forum and i'm sure you'll find some instructions.


but had less torque than most cars (but lots of power)



Torque and power are related.. torque equals power in RPM's below 5250. possibly explain more


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