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hello i tested the compression on my 71 240z and all six cyl.read at 135 after 3-4 cranks...is this a problem too low..ok or ???? also what temp should the car read with a meat thermomiter mine reads at 190 but higher in traffic....
 

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Throttle Blocked Open?

Make sure you have the throttle blocked WIDE open or you will get low compression readings.
Normally on an early car, 180 is in the area of new. For a turbo 140.
Do a "Wet Test" and see if the numbers rise. If they don't, you probably are in need of a valve job. If they do, your rings are wither sticking, or worn...
Therr-to-five cranks on a FRESH BATTERY are all you need to get max compression.
I'm partial to screw-in gauges, but the ones you hold in work in a pinch. I just don't like them--too much work...
 

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Like Tony said, make sure throttle is wide open. Also the manual calls for a WARM engine so be sure to warm is up fully before testing. It also says that it is measured at 300-400 rpms with all spark plugs REMOVED. With a full battery and good starter it should spin fairly close to this but if it is spinning slower you might get lower readings. If this is a daily driver and not a racer I would much rather have all six reading a little low and maybe have to feed a small oil habit than having wide differences between cylinders. At least with all reading the same you don't have a blown gasket.
 
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