Allis Chalmers B Barely runs

[thdrduck]

Years ago when I did more engine work I took an old spark plug, knocked off the insulator and brazed an air quick connect on it. You bring the cylinder being tested to TDC compression stroke, screw the thing in the plug hole and put a little air to it. Air rushing out the crank case vent = leaking past rings. Air out the muffler= leaking exhaust valve. Air out the carb= leaking intake valve.
I even used one once to change valve seals without taking the head off. I had a couple different sizes laying around, don't know what happened to them. Might give you a better idea of what you are dealing with before you tear into it.

 

[jimtrs]

(quoted from post at 10:14:46 03/08/23)
Understood, I changed plugs and wires and it runs far better than it did, it will idle but with slight surging

Surging is probably a minor governor adjustment

but I am concerned that I will have to replace the valves since adjusting the carb and timing on the mag had little affect on run quality and I adjusted the valves prior to startup

Adjusting valves to correct lash and not seeing a change in how it runs is not the way to identify bad valves. Especially if the adjustments were minor.
A compression test and a leak down test will identify a valve problem.

however it still sputters a little

I'd be looking closer at the carb again. Possibly running lean ??

also what is a decent oil pressure for these engines, the original gauge did not work so I put one I had lying around on and it holds 20-23 psi.

Not sure of original spec but holding 20+ is very good, especially when hot

 

[CONSERVATIONMAN]

WOW

A lot of good ideas, I hope I can remember them If I ever have any trouble

( everything is runing OK now )
Wally