Compression checks

[karlp]

Just wondering...
I am planning to pull my motor after xmass to fix the front main seal and may start the " while I'm in there........" routine.
Should a compression check be done while the engine is stone cold, warm, close to operating temperature, with or without a table spoon of oil or all of the above?

When I first got it I checked with it completely cold and it was ~100 psi on all four cyl.
I am burning a fair bit of oil and would like to separate valve guide burnage from P$C burnage.

Any help would be greatly appreciated.

Thanks, Karl

[John Rogers]

The way I do a compression check is as follows: assemble necessary tools, warm engine well, remove all spark plugs, put on batt charger (full batt power), lock open throttle at full, install compression tester on #1, crank engine and count number of REVs till full pressure, record reading, put tester on next cylinder and crank SAME number of REVs, record reading, repeat for others. Return all to before test. Note, you could pull the line at the distributor for the injector points but I found it did not make any difference in readings. Good luck.

[maf 914]

John,

Should the fuel line be disconnected? Cranking an engine without ignition can pump a lot of gas. I know this from removing the plugs and cranking to get oil pressure. That gas really flies!

Mike

[John Rogers]

You did not say what type of induction, carbs or FI? You could pull the fuse for the fuel pump in either case if you are concerned, but I've never done it. If there are carbs, pumping them will shoot fuel because of the accelerator pumps, but I block the throttles wide open so that does not occur. Good luck.