Quote:
Originally Posted by Flathead Fever
Did the engine sit for awhile? It might have a stuck open intake valve. That will disrupt the flow in the intake to the other cylinders. It really messes with an engine. The piston is pushing air back into the intake and screwing up the flow to the other cylinders. It would also probably have a fairly loud lifter noise if it an intake valve were stuck open.
My 82 year old dad has a 8BA powered, '32 roadster (see photo) that has sat in his garage for years and years. It ran perfect when it was last driven. It was probably ten-year's or more since it was last started. The fuel was so old that new fuel would not flow through the metal fuel line, it turned solid inside the tube. I can't even get a welding rod to go in the tube. I gave it an alternative fuel supply and got it started. One lifter is loudly hammering away and it will barely run. Its a unique sound, it sounds like its running on 4-cylinders but its a different sound than if you just had 4 cylinders not firing. I'm positive an intake valve is stuck open. One of these days I'll pull the intake off and unstick the valve.
They took away dad's driver's license because he refused to try and control his blood sugar. Apparently eating a tub of ice cream a day is more important than being able to drive. If he could drive I'd fix the car.
Diagnosing.
First thing to do is put a vacuum gauge on it when its running. Any valve problems and that gauge needle will be jumping.
When you do a compression test make sure to have the throttle open so the air can get sucked in past the throttle plate.
Pull all the plugs and pressurize each cylinder on top dead center of the compression stroke with a rubber tipped blow gun. If the air comes out the intake you have an intake valve problem. If It comes out the exhaust you have a exhaust valve issue. If it comes out the oil breather you have bad rings or a hole in a piston. If it comes out the next door cylinder you have a blown head gasket. If it comes out the radiator you need go get a box of tissues to wipe away your tears.
Before bore scopes we use to also have what we called the "dipstick test" at work. If you pull the spark plug and can check the oil through the spark plug hole with your dipstick, it fails the "dipstick test". Your valve went through your piston. This was a real test. It saved us from wasting time pulling the engine apart. We then ordered a factory rebuild.
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That roadster looks like a beautiful car. Too bad it has to just sit.... Mark