Compression Test

Hi All,

I am new to the H.A.M.B, but have a few questions about running a compression test. I have a 1951 Hudson Commodore 6 with a straight 6, 262, Flathead. I have pulled the engine out of the car, which was seized, and attached the transmission to another 262. I am trying to run a compression test on the ground, but I have ran into a few problems. When I attached wires from the negative terminal to the bolt on the starter motor, and the positive terminal to the block(The car is a 6 Volt Positive ground) the starter motor will spin. But it doesn't receive enough amps to kick the starter motor wheel out so that it can catch on the flywheel. I thought my problem was I wasn't using a starter solenoid, causing the starter motor to not receive enough power.

Am I correct in thinking this?

How can I then wire the bunch together so that I can run a compression test on the ground?

Thanks, Paul

 

I am not in my shop where I have a wiring book for those years. I could have looked to see what system it uses to crank over.

Some cars had a starter foot button, some had starter solenoids or relays, some had a pedal to engage the gear.

So, I don't know what you have. If you think it's a normal vintage starter with the bendix drive that spins the gear in, then try a 12v battery. If you are only jumping the starter, the starter won't care if you use positive ground or not.

Have you looked at the spriral threads on the bendix gear, looking for rust?

 

A picture, or even a good description of your starter will get you a lot more pertinent answers. That said if it has a starter mounted solenoid I would put 12 volts to it, polarity doesn't matter at this point, hook to the main post, and then short from there to the little post on the solenoid that kicks the drive in. Sounds like you could just be motoring your starter. If it has a carb on it, tie the throttle wide open, and do your compression test. Then put a teaspoon of oil in each cylinder and repeat the test. Results should tell you quite a bit about the condition of your engine.