vibrations

VW underneath a classic Italian body design.
vibrochimp

vibrations

Post by vibrochimp »

My ghia 1966...feels like it has solid motor mounts ...I have replaced them all in the last year and checked the tightness of the engine bolts as well...and the transmission bracket...around town driving not so bad but I don't feel so good on the the freeway about it..any ideas ? thanks
Air-Cooled Head
Posts: 1684
Joined: Fri Nov 23, 2001 12:01 am

Post by Air-Cooled Head »

When you say changed motor mounts, whadda ya mean? And the tans bracket? Is that a tranny strap that goes around the frame horns, or the rear trans mount that attaches to the ends of the frame horns? A clearer explaination would help.
vibroghia

vibration

Post by vibroghia »

yes the two motor mounts and trans mount were replaced...but not the bracket for frame horns..the mounts are the stock rubber type.
vibrochimp

vibration

Post by vibrochimp »

a slight roughness at idle but feels like a go cart type vibration through out the range...cruising about 40-45 mph in 4th gear is fairly smooth and quiet....engine is a stock 1600 has a new clutch and flywheel .
vibrochimp

vibration

Post by vibrochimp »

I have been trying to think of a description to what I feel...on the car...
It is like it has a solid braket is going from the engine to the body...and I can feel "general" vibration not nessesarily going with engine speed . The engine has good power/performance. thanks for your time
vibrochimp

vibration

Post by vibrochimp »

I have been trying to think of a description to what I feel...on the car...
It is like it has a solid braket is going from the engine to the bodysheetmetal...and I can feel "general" vibration not nessesarily going with engine speed . The engine has good power/performance. thanks for your time
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Max Welton
Posts: 3026
Joined: Mon Jun 03, 2002 12:01 am

Post by Max Welton »

Maybe a few more questions will help us understand.

Does the vibration exist when the car is not moving (reving the engine while in nuetral)? If so, does pushing in the clutch change it at all?

Did the vibration appear recently? Did the appearance of the vibration correspond with any changes to the vehicle, such as maintenance activities?

Max
vibrochimp

Post by vibrochimp »

Ok.... the vibration is present when car is stopped... pushing in clutch has no effect... reving up in neutral only increases it a little bit ...I did put a new clutch and flywheel in a few months ago and had some trouble with a different vibration ..the lower engine bolts got aluminum in the threads so I had to take the engine out clean the threads and now I believe the bolts to be truly tight. I felt the transmission while the cae was idling from underneath and it seemed like the noise was coming from the top of the engine... I tried running it without the belt but noise was still there...just puzzling,, thanks
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Max Welton
Posts: 3026
Joined: Mon Jun 03, 2002 12:01 am

Post by Max Welton »

Good. We have now established that nothing in the transmission is likely to be the root cause. And the belt-off test rules out the fan and generator.

Two things come to mind.

One: The flywheel may be loose.

Two: The engine's combined rotating mass (crank,pully, flywheel, pressure plate) is out of ballance.

Since you recently replaced the clutch and flywheel, I strongly suspect the latter. What prompted the replacement?
vibrochimp

Post by vibrochimp »

I replaced the clutch and flywheel before because of the other vibration that did vary with engine speed ..the old flywheel checked out ok ..it was tight...but I changed it anyway since I had the engine out and put a fresh
clutch in it...this was when I discovered the aluminum in the threads of the lower bolts..A little problem in stabbing it the previous installation no doubt....so I wasn't getting proper torque on the trans-eng connection...
after installing it then it was a lot better with respect to the engine speed to vibration ... I even went through the sheetmetal to replace missing screws....the front crank pulley is the original since I've had this engine...about 70k miles.... thank you
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