compression

1948jr · Dec 21, 2013

what is the best way to do a compression test on a tractor

Janicholson · Dec 21, 2013

Charge the battery
Remove all spark plugs
Open the throttle
Use a screw in compression tester that has been tested against a standard
Be sure it is in neutral, and block down the clutch pedal (easier to spin the engine)
Crank the starter six long enough to compress each cylinder 6 times. Mark the results on paper.
Squirt about a teaspoon of oil in each cylinder.
Spin the engine about 10 strokes or so to spread the oil, then recheck the compression. and write it down under the first set of numbers. Jim

super99 · Dec 22, 2013

I would add; put a clothes pin on each plug wire numbering them so you don't get them mixed up when finished. Chris

Allan in NE · Dec 22, 2013

Actually Jim

That "checking compression with oil" is an outdated procedure (by about 80 years).....as a used engine will ALWAYS show bad rings.

Either the engine has compression or it doesn't; if compression is bad, the head has to come off anyhoo.

Allan

Janicholson · Dec 22, 2013

in discussion/not disagreement, I have found it to be helpful distinguishing between the beginnings of an intercylinder head gasket leak, and rings. Valves are usually so bad that a dramatic low pressure is going to be found in one hole. Just me. Jim

compression

1948jr

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Janicholson

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super99

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Allan in NE

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Janicholson

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