TO-20 Compesssion Test...and Maybe a Screw-up...

I ran a compression test on my 1950 TO-20 today. (First time ever doing a compression test on anything. Thanks, O"Reilly loaner tool program!)

Dry numbers (1 through 4) were 90,90, 85 and 90.

Wet on #4 was 100, but it"s the only cylinder I checked wet - my pump oiler quit, and I didn"t have a good way to squirt a small amount of oil into the cylinders. (I didn"t want to make another trip to town today.)

I"m investigating a small coolant leak on the left side of the engine at the head gasket, between cylinders 1 and 2, as described in the linked thread below.

The previous advice was (a) check compression, and (b) re-torque head.

I didn"t think those compression numbers looked too bad, based on what I"ve read in the archives, so I"m inclined to retorque the head, while I have some other stuff apart, rather than jump into replacing the head gasket. Does that sound reasonable?

Also: the loaner gauge was designed to fit two different sizes of spark plug holes. On the TO-20, the smaller fitting just goes right into the cylinder, and the larger fitting threads into the spark plug hole, and seals with an o-ring.

The problem: the smaller fitting also has a o-ring, and at some point during the test the smaller o-ring disappeared.

I couldn"t find it on the floor, so I"m assuming it fell into one of the cylinders.

When I was through, I re-started the tractor, and after the smoke cleared from the "wet" test, everything seemed fine.

Should I worry about that where that o-ring might be?
Other Thread About Head Gasket...

small coolant leak?any in oil?if no,and it doesnt bother the way it runs,leaveit alone.and the o ring-never mind.it"s gone wont hurt anything.been there screwed up!

Thanks, Jon.

No, there"s no coolant in the oil, and no oil in the coolant. Starts and runs fine.

Now, I am planning to remove the gas tank to clean/seal/paint it, and I need a new manifold gasket, so "while I"m at it" I"ll probably re-torque the head.