BMAN in Detroit
New User
I am trying to get an unstuck 720 gas back running. I have removed everything from the tank down to the head block and crankcase sitting in the chassis. I was hoping to find that this engine is tight enough to be reassembled, fired up with fresh oil and able to move under its own power. I just tried to do a compression test and I saw what I believe to be really low numbers. I saw about 70 on the flywheel side cylinder and 80 on the clutch side. I had a note written down from years ago that you should see 120 psi on a cold engine.
First question: Is a compression test a viable diagnostic test with a tractor that is 67 years old? (I used a Mac compression test kit)
Second question: If this engine is 'tight' should I be seeing pressures in the 120-140 range cold?
After doing the compression test, I hooked up compressed air to each cylinder. On the flywheel side, I had a lot of air coming back through the crankcase. On the clutch side I could see water scale dust coming up out of the water jacket of the cylinder head, (this thing has been drained of coolant for a while sitting inside a building).
Third question: With air blowing back into the crankcase, is that a telltale the rings are broken and or shot?
Fourth question: With what I have described, am I at a point the head should come back off and the pistons removed to see how bad they are?
Let me know your thoughts and or insights. Thanks in advance for your input.
First question: Is a compression test a viable diagnostic test with a tractor that is 67 years old? (I used a Mac compression test kit)
Second question: If this engine is 'tight' should I be seeing pressures in the 120-140 range cold?
After doing the compression test, I hooked up compressed air to each cylinder. On the flywheel side, I had a lot of air coming back through the crankcase. On the clutch side I could see water scale dust coming up out of the water jacket of the cylinder head, (this thing has been drained of coolant for a while sitting inside a building).
Third question: With air blowing back into the crankcase, is that a telltale the rings are broken and or shot?
Fourth question: With what I have described, am I at a point the head should come back off and the pistons removed to see how bad they are?
Let me know your thoughts and or insights. Thanks in advance for your input.