I bought myself a 1951 Ford Custom not long ago and had a question. When I'm driving around 45 mph, I get a vibration. Don't get it at 50 or 40 just at 45. Also, when it's parked and I rev the motor, I can get the same vibration. Is it possibly the clutch assembly or an unbalanced flywheel? Or is it maybe in the motor itself? It is a rebuilt 239 flathead V8 with low miles. Runs great otherwise.













61 F100 292.







51 Ford Custom

Try it with the fan belt removed to rule out the fan.  If the vibration remains, all that is left is the flywheel/clutch or the engine itself.

John - "The Hoosier Hurricane"

Does the engine have the same vibration with the clutch depressed?  Have seen some clutch disks with high amounts of imbalance but these can usually be identified as the engine being vibration free with the clutch pedal depressed.  After doing as John suggests, the pressure plate would be the next item to check and then you're into the flywheel.  Beyond this, you are getting into the engine itself.

Lorena, Texas (South of Waco)

Ignition timing/curve? Too much vacuum assist advance at cruise could induce a rough-running engine vibration. Turn down your initial timing and see if vibration comes at a different speed?

6 VOLTS/POS. GRD. NW INDIANA

Thanks guys, I'll try your ideas and hopefully find the problem. Too busy with car shows this weekend

61 F100 292.







51 Ford Custom

I know this is going to sound weird but......I entirely rebuilt a 1967 corvette 327 and it's 4 speed and had a vibration. The engine had been balanced etc. I thought the rebuilder had done something wrong. They checked it out and found the engine and tranny were fine but still the vibration. I had put in a new Borg Warner pressure plate and disk. The plate had been balanced with the flywheel. I drove the car and while on the freeway, kept my foot on the gas simulating cruising and depressed the clutch. Everything was still spinning.... except the frigging disk!!!!!! It was hugely out of balance. Of Course Borg Warner never makes a bad product so they shined me on. I bought a new disk, not BW, and had it checked for balance and it was fine. Vibration GONE!!!!!!!

John Casey

1950 Ford Woodie-Rodded

1957 TBird-somewhat rodded

San Diego,CA