viberation at mid speed

J

jerry shook

Well-known member
I have a 1931 slant window. at idle the engin runs smooth as you increase the rpm at about half throttle it viberates the steering wheel real bad as you increase to a higher rpm its smooths out. this in only in the wheel very little any were else. this is with car setting still, when you are driving it does it to the same way . HAVE ANY SUGGESTION ???. I did put the float a motor on front and back.
 
Hi Jerry,

I have seen that the front and rear float-a-motor mounts together will sometimes cause the motor to move more excessively than only using the rear ones.

You might also want to look at what mechanical linkages might be causing the vibrations to migrate to your steering column (Throttle and advance rods might be bound up, telegraphing the vibrations) the column might be a little loose a the frame mount, a steering rod touching the oilpan, or even loose front end or wishbone connection under the transmission might be telegraphing the vibration.. These cars do vibrate a bit and often they will have a sweet spot on the upper 1/3 of their RPM range where the vibration is less..

Hope one of these ideas helps-

Dave in Boise
 
First, try the easy stuff:
Run it with the fan belt off to see if its fan or belt related

Those front float o motor mounts that require you drill the cross member are notorious for increasing vibration. If the bolt touches the cross member it will shake your fillings out. The original ford design mount works better.

If the problem existed prior to installing the front mount follow these threads for much discussion on that matter:

http://69.61.21.195/forum/showthread.php?t=8984&highlight=engine+vibration

http://69.61.21.195/forum/showthread.php?t=6707&highlight=engine+vibration
 
I have found that my stock '28, with original motor mounts, sometimes vibrates more noticeably between 35 & 45 mph, according the speedo, depending on what sort of "mood" the car is in on a given day...

Some days and some roads it "buzzes" more than others... if it's being particularly "buzzy", I try to speed-up or slow down enough to get-out of that vibration.

Not saying you shouldn't check-out the itmes mentioned in the other posts, but I believe there is some inherent harmonic vibration around this speed range that is somewhat the nature of the beast...
 
Mine has no vibration unless it gets over 60, then it is very
slight. Not a problem for me since I seldom drive over 55.
My sweet spot is about 45 to 50, and that is where I drive
90% of the time.

Jack
 
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