Anybody have any thoughts on this?

[Rumble1960]

Hello all, new here and recently purchased a 1960 D100 the last year the flathead was available in a Dodge truck. I've been working on an intermittent vibration since I got it, so far I have replaced spark plugs, coil, wires, cap, rotor and points. Set the timing, removed the distributor checked and lubed the advance weights, and just yesterday set the valve adjustment. I set the valves the static way (engine not running) and also with the engine running and found either way yielded the same results. The engine compression is 120 to 125. Even though this vibration is also apparent in neutral when revving the motor I did pull the drive shaft so I could insure the U joints were good and they were, I did find that the arrows on the drive shaft and yoke did not line up so I corrected this, it made no noticeable difference. Now I am at the point suspecting the clutch because it seems that if I'm in 3rd gear going down the road and I feel the vibration I can push the clutch in rev the motor a couple of times and release the clutch almost every time it smooths out and as long as I don't push the clutch in again it stays smooth, I can slow right down speed up what ever it stays smooth till the next time I have to stop. I'll go through the gears same thing all over again. I pulled the inspection cover off the bell housing the clutch has a rebuilt label on it but from what I can see looks ok, the release bearing seems to have a lot of play but does not make any noise. Anybody have any thoughts on this?

[55 Fargo]

How are the motor mounts, you mention the clutch,maybe it's not aligned correctly when last installed, maybe there is a balance or some problem with the flywheel.

Not sure if either of these items can cause what problem you are experiencing, or if this has something to do with the engine internally.

I take this engine is a 251 Canadian built engine being your in Ontario?

Hope someone else will chime in with better advice, welcome to the Forum BTW..........Fred

[greg g]

Hello and welcome. Before tearing the thing apart to check the clutch, give a quick check to the condition of the Vibration damper. These can sometimes begine to delaminate causing a shake. Also check the condition of the front motor mount. There is a rubber isolator between the pieces at the top where the engine bolts on. This Floating power piece is also prone to delaminating from its surrounding metal. Both pieces should be available from Vintage Power Wagons. Or as in a previous post, the DAMPER DOC can repair your damper. You might also give a look to the parking brake and make sure it is releasing all the way and make sure the drum is not bent.

What is the frequency of the vibration, is ti timed to the engine or timed to the drive train??

[Rumble1960]

How are the motor mounts, you mention the clutch,maybe it's not aligned correctly when last installed, maybe there is a balance or some problem with the flywheel.

Not sure if either of these items can cause what problem you are experiencing, or if this has something to do with the engine internally.

I take this engine is a 251 Canadian built engine being your in Ontario?

Hope someone else will chime in with better advice, welcome to the Forum BTW..........Fred

Thanks for the welcome, the truck came out of the US and is a 230 motor, when I had the inspection cover off I did loosen the pressure plate hoping it may align itself better, but this did not make any difference. As far as the flywheel I'll have to wait till I pull it apart to check it's condition. I just went on a 30 mile drive and I could get rid of the vibration every time in 3rd gear by pushing in the clutch and letting it up slowly while coasting along, it seems to be very sensitive to how it is engaged.

[Rumble1960]

Hello and welcome. Before tearing the thing apart to check the clutch, give a quick check to the condition of the Vibration damper. These can sometimes begine to delaminate causing a shake. Also check the condition of the front motor mount. There is a rubber isolator between the pieces at the top where the engine bolts on. This Floating power piece is also prone to delaminating from its surrounding metal. Both pieces should be available from Vintage Power Wagons. Or as in a previous post, the DAMPER DOC can repair your damper. You might also give a look to the parking brake and make sure it is releasing all the way and make sure the drum is not bent.

What is the frequency of the vibration, is ti timed to the engine or timed to the drive train??

Thanks, a couple of good suggestions I will check both. The frequency of the vibration is related to engine rpm.

[Rumble1960]

Well I did check the other thinks mentioned and everything checked out good. I'm now convinced it's the clutch, depending on how it engages it will vibrate or it will be smooth. I'll be pulling it out in a couple of months when classic car season comes to an end here. It will be interesting to see what I find I suspecting broken or week springs or maybe a bent release finger.

[Norm's Coupe]

I suppose the clutch could cause a vibration. That said, I bought a new 1965 Dodge Cornet slant six in 1965 with 3 on the tree. Not long after I had it I noticed a clunking noise in high gear at freeway speeds between Louisville, KY and Chicago, IL. Got to Chicago, took it into the dealer. They said the pressure plate had tightened up against the flywheel. Not sure how that happened, but that's what they said they fixed and it never did it again. Was under warranty so really didn't care about the details at the time.

Don't remember any vibration at the time except when it clunked. Of course that was long ago. I do remember stopping about halfway at a dealer in Indiana to check it out though due to the noise it was making. They said it should be ok to drive to Chicago that way, so I did.

[Dodgeb4ya]

Another thing to check besides just the clutch is if the flywheel surface is machined perfectly perpendicular to the crank-ie surface runout. I had a Camaro that had a bad flywheel resurface job that caused a real bad engine vibration . Runout was .020". Should be about a max of .005. The flywheel was turned on a brake lathe! Bad idea! Always should be machined on a flywheel grinding machine by a good machinist.They can check it out for you if you don't have a dial indicator.

Bob

[Oldguy48]

This may or may not be related to your problem, but I had a 57 Dodge pick-up clunker with the flathead in it, & one day it make a heck of a clatter. Turned out to be the bolts holding the flywheel to the crankshaft. Pulled things apart, and discovered the loose bolts. After tightening them, the problem disappeared.