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Received my compression tester in the mail. Tried it out and got no readings (but engine did not turn over that strong either). Put my finger over the spark plug holes and could feel compression but read somewhere that doesn't tell much. So got my carburetor rebuild kit and took off my carb today. I think you are right with the stuck intake valves. The intake manifold was full of gas. I am thinking that must be gas not getting in because of stuck valves? If that is the case do I pull the valve access cover or pull off the manifolds to check it out? Or is it something else? Have my resistor and seafoam coming. Maybe i will work on cleaning up my carburetor while I ponder and wait for your suggestions. Thanks as usual. Phil
Yes, stuck intake or exhaust valves will prevent a vacuum from forming in the cylinder when the piston is on the intake stroke, so any fuel mixture that was drawn in will just get pushed back out into the manifold. You may also have stuck exhaust valves as well. In my case with the updraft carburetor and high exhaust manifold in the COE cab it was easier to just pull the head (opportunity to inspect the cylinder walls for ridge and wear) and squirt Kroil down the stuck valve stems and gently and carefully tap the valve down with a plastic hammer as I turned the engine over. This was the final result (it wouldn't idle down due to a vacuum leak):
Well, I have the carburetor off, I might as well pull the head and take a look at everything. And hopefully unstick some valves. I'll let you know what I find. Thanks.
Things slowed way down for me, but I finally was able to remove the cylinder head. There are no stuck valves. As I turn the engine over by hand they all seem to go up and down with none staying up or down. I can't really understand the sequence but they all seem to know what they are doing. The pistons seem to be okay. No scarring on the walls and they go up and down smoothly. Everything seemed a bit dry though. I honestly don't know what it all should look like. Since everything is open should I do some sort of lubricating in the cylinders and pistons? And how about the valves, any lubricating? At this point I am wondering if I should remove the manifolds just to clean them up or is that a difficult job? And is that going to make a difference in trying to start the truck? They look pretty rusty and I am worried about breaking bolts. Suggestions? Have been unable to get time to do my carburetor. Maybe this week. And I don't know what to do with the gas in the manifold. Is there a way it should drain out or should i use a turkey baster and try to suck it out?
The engine has been overhauled at some point because the valves are aftermarket. Can you tell if there is much of a ridge at the top of the cylinder walls? Are there any numbers stamped on the pistons? All in all it appears pretty good and clean, but some of the valves may not be closing completely - you can test with a strip of paper. And having sat idle for so long the rings could be frozen in the lands. Try putting the pistons at half way and soak them with penetrating oil for a day or so, it may unstick them. It really shouldn't be necessary to remove the manifolds, but you could blow compressed air through them to prove all the passages are clear while turning the engine over.
Okay, the valves passed the paper test. All pinched the paper so I could not pull it out. I have included some pictures of the valves. Only one had a number on it and others had ford usa. It looks like there is a difference between the valve types on mine (yours were all the same). I also have included a picture of the number on the piston and a close up of the top of the cylinder wall. I have some left over marvel mystery oil. Should I use that to soak the pistons? I have a close up picture of the vacuum line which shows it's okay. Thanks. Phil
Standard bore. Nice! Maybe it just had a valve and ring job at some point. It looks like there is maybe a .002" to .005" ridge on the cylinders, see if you can catch a fingernail on it. Might need a ridge ream, maybe not if it was performed with the ring job. The Marvel Oil would be fine for a soak but I would mix it 20% with a clean aromatic hydrocarbon such as lacquer thinner or MEK for deep penetration. I might add that the pistons and upper cylinders look remarkably clean, so that suggests that the engine was tuned correctly and it wasn't an oil burner.
Got the piston soak going. There is a very slight ridge on the cylinder walls but not enough to catch a fingernail. I can just kind of feel it. If I needed to slide a piston out it would easily come out. I think they are okay. Do I need to do anything else with the valves? Phil
This is what I did:
After un-sticking my valves I cleaned the seats and valve faces with a small brass wire brush and lacquer thinner for a better look-see. All looked pretty good so I put a film of grease on the seats and rolled the engine over a few times, took another look, and slapped the head back on. Having an updraft carburetor makes it a little more difficult to start under those conditions so I gave it a shot of ether, and after about four revolutions it took right off as per the smoking video. I also used Rector Seal on all of the cleaned headbolts, torqued in two stages, and re-torqued after running. Make sure your spark plugs are clean, gapped, and dry.
Still don't know why the gas was not getting to the cylinders. Mixer man said maybe some stuck valves. But I did not seem to have any that were stuck. I tried to use high pressure air to blow into the manifold. My next thing is to get the gas out of the intake manifold and then blow air again. Rotate engine and blow some more (as had been suggested). Still have to rebuild my carburetor. Maybe I just dumped too much gas down the throat of the carburetor and flooded it to the point where nothing could happen. I don't know, Mixer man? I'll keep plugging away. I feel like my chances are improving with the pistons, valves and cylinders looking pretty good. Again, thanks for the help. Phil
Maybe I just dumped too much gas down the throat of the carburetor and flooded it to the point where nothing could happen.
I wasn't aware that you poured gas down the carburetor. Yep, that can easily flood it to that point. Next time just use a full choke for a few revolutions, then half choke to start. A small shot of ether may be required because of the residual "soaking solution" dampening the spark plugs.
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