I've got a vibration in my forty one ford. It's got a rebuilt 8cm mercury flathead And the stock rebuilt transmission and old stock rearend. New Fort Wayne clutch that works beautifully and smooth. Between 2220-2800 RPM just about cruising speeds It has a bad vibration in the driveline and if I push the clutch in and keep the gas where it is and then let it back out. I can find a spot where the car doesn't vibrate all and keep driving. When revving the engine stationary, sometimes it will vibrate and sometimes it will not. IVe taken all the belts off to eliminate that and no difference. Almost seems like the clutch and fly will are out of balance with each other. I did not get these balanced when I added a part. When I got the Rebuilt trans,I figured I should inspect it just because and found that the thrust washers were missing And maybe I missed something else in there. Like the front bearing, but it seemed new. Any thoughts anybody?
They forgot the thrust washers?! What kind of end clearance did they have? Measure in tenths instead of thousandths. With work like that, my first suspect would be the transmission. Each of the flywheel, pressure plate, and everything rearward of there should be balanced individually. We hope that parts are good ( new and old), but plenty of opportunities for “not quite”.
First, thanks for the full description and pictures! Really helps to wrap the noggin around the issue. The thing that jumped out was driveline angle due to the lowering. I doubt this is really causing it, but I'd check things. With your description of it being able to be 'reset' not to vibrate using the clutch, I'd suspect it's in this area. Pilot bushing/bearing wear, clutch uneven, front input shaft bearing (front or rear), and check bellhousing and trans mount bolts.
Yes, that's the weird thing, as I can basically reset it as you said and make the car not vibrate. Everything was new as far as the pilot bushing. And the clutch and the throw out bearing. And I'm pretty sure I may have replaced the front bearing in the trans.
Needle bearings between the main and input or surfaces? Just a WAG... If you have a helper, have them push in the clutch and see what moves when side load is applied to the disc?
I had a vibration problem with my 58 Impala that I could solve by pushing the clutch in and letting it back out. What I found was the pilot bushing in the crank had split and part of it was gone. I always step on the clutch pedal before starting the engine. The weight of the clutch disc would cause the disc and the trans input shaft to get off center causing the vibration. With the engine running the disc would end back on center when you pushed the clutch in. Don't know if that is your problem. I really don't understand your description about pushing the clutch in and keeping the throttle steady.
As far as keeping the throttle steady. I'M going down the road at 50 miles an hour and I do not remove my foot from the gas pedal. Keeping it the same RPM and I just push the clutch in and out a couple times. I'm thinking the pilot bushing may be bad even though I replaced it. Can't remember if I put a bearing or bushing in it. Maybe I have some pictures.
Well, it sounds like it's either or both of the pilot bushing,Or the input shaft bearing . Either way, something's gotta come apart.
It could also be imbalance additive. In other words, if the flywheel/pressure plate have a slight imbalance, and the clutch disk also does, when the imbalances end up in alignment they could cause a vibration. Pushing the clutch in a couple times would realign the imbalances such that they could be cancelling each other.
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