The Stovebolt Site Forums The Shop Area Engine Shop 235 Engine Compresion Numbers and Problems

My 58-62 235 has 150 lbs of compression on cylinder #1, 130 on #2, 130 on #3, 90 on #4 and leaked down quick, 140 on #5 and 120 on #6. It smokes like a freight train I assume because #4 cylinder spark plug was fouled with oil. All others looked good. # 1 was a little sooty but the rest were fine. The car had sit for several years and the gas was really bad.

I have a 261 that I can replace it with but would like to save the 235 just to put around in while I build the 261.

Could the valves and/or guides be the problem?

could also be that the rings are a little frozen up or worn.

Kurt

Maybe some Marvels Mystery oil in #4 might unstick a ring?

Worth a shot for sure. Don't run it too hard.

Kurt

Found the culprit, the number 4 cylinder push rod was bent. I seem to remember my old 52 chevy having the same problem 45 years ago. When the push rod would bend the motor would smoke like a freight train. Replace the bent push rod and the smoke went away. Put in a new push rod, adjusted the valves and it purrs like a kitten after sitting in a shop for 12 years. The carburetor needs rebuilt as it won't run without feeding gas by hand. Haven't checked the fuel pump pressure yet and it may also be bad but I am encouraged with the outcome so far. Keeping my fingers crossed....

Hey Snowball -- for us non- mechanic types -- how did you know the push rod was bent? Was it obvious, as in not straight, or was it something you just tried and had success. I have one tapping, not sure which, and lots of smoke. Not to hijack your thread, just wanted to know what you saw, heard, or how you determined it was bent.

Thanks,

Dale

Hey Dale;
It might be as simple to find as pulling the valve cover and watching the pushrods as in this VIDEO

Good luck.

Thanks Waldo! - the video really helped -- it was very clear that pushrod is bent! Now I know what I might be looking for. This has been a good thread.

Dale

I am at a loss to figure out how a bent pushrod makes it smoke. How does that cause it to smoke?

If was an intake pushrod non-opening intake valve would result in vacuum in cylinder when exhaust opens pulling oil past exhaust valve guide directly out into exhaust manifold.

Oh, that is something. So the burning is taking place in the exhaust itself. Thanks for the explanation.

The video shows a push rod that is really bent. I found mine by twirling the rods under tappet and you can easily see one that is even slightly bent.

After rebuilding the carb and replacing the fuel pump, intake/exhaust manifold gaskets, push rod and plugs it started right up and purrs like a kitten. I took it for a spin around the block and it was a blast. The brakes, steering and suspension need some work but not much. I can't wait to get it out on the road.

They are much more interesting to drive than today's vehicles.