Ford 350 engine vibration

oldthreetimer · Aug 20, 2015

My 1956 Ford 850 (not 350, as I posted a minute ago) has suddenly developed an engine vibration at around 1200 rpm. I've got it apart now, so I can't do other tests, but it vibrated at that speed even in neutral. An oil leak that developed at about the same time might be related or it might just be that I inadvertently overfilled it, because it stopped once the dipstick stopped showing a little bit overfull. A tractor mechanic doubts my theory, that it's a main bearing going, and my tests for play on the crankshaft pulley tend to agree -- they show hardly any play at all. He thinks it might be a clutch problem. Any ideas?

tmajor · Aug 23, 2015

I had a car with a standard transmission, which would vibrate the starter off .... or loose, if you caught it in time. Turned out to be, the flywheel was out of balance. I believe, I had changed to standard shift from auto. ?? Or, I might of had the engine rebuilt.

oldthreetimer · Aug 24, 2015

tmajor said:
I had a car with a standard transmission, which would vibrate the starter off .... or loose, if you caught it in time. Turned out to be, the flywheel was out of balance. I believe, I had changed to standard shift from auto. ?? Or, I might of had the engine rebuilt.

Thanks for your theory. New info -- about the front-mounted hydraulic pump system. I found a bent bolt and some loose ones in the pto shaft and on the pump mount. That shaft is always spinning when the tractor is running. I wonder if the created enough wiggle to make the vibration.