Just picked up a new vibration in my 69. Soon as the car hits 50mph it starts vibrating. Could this be the drone from my Flowmaster exhaust system or could it be in the drive train.
The tires are like new and balanced and the suspension is all new.
The motor mounts are also new and so is the trans, clutch etc.
Schoon

Heres some stuff I found for you, I just copied the whole thing

My chevelle is a 19000 mile car but it sat from 1978 to 2004 The car is fine below 50mph but vibrates badly from 50 on.... I am going to replace the U-joints since it is a 4 speed car. Could it possibly have a bad tail bushing also? The vibration is worse off power but does vibrate on power as well. Only abouve 50 mph though.


Have the driveshaft checked for straightness and have it ballanced too and you will hopefully correct the vibration.

If it still vibrates after that check the trany yoke and tail hosuing bushing and replace them if they are worn/sloppy.

Hows the pinion bearing?

Just a thought,does it vibrate with car stopped in neutral when you rev the motor (with the clutch out/engauged) to the same rpms as when your running down the road and its vibrating?

If yes then its an out of ballance rotating assembly in the motor,or a bad harmonic ballencer,out of ballance clutch assembly & flywheel,etc.

The car is very smooth until 50 mph no engine vibe or tire wobble. pinion bearing seems tight. I guess I'll know more after the u-joint replacement

Check for a bent wheel or tire with a broken cord. Cords will sometimes cause a bulge and sometimes not. Good luck.

U-joint- A friend of mine bought a clone '69 Trans Am, that had sat for 8+ years, and had a major vibration. Both U-joints had seized up , and as he approached 45mph, it started vibrating. Anything above 65mph, and it was all he coud do to hold it in the road. He changed them out, and the problem went away.

Rob

Thanks!
I will check it out.

http://csgbenefits.org/camarovibration.pdf

Try that PDF file. It is all about vibrations and tracking them down.

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Regarding the Flowmasters drone making you think it's a vibration. Try driving the car, and then put ear plugs in, to see if the reduction in noise makes the vibration go away.

Man, I love my Flowmasters, but I hate the interior drone. I just wish there was some way to tune the exhaust to get rid of interior droning.

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tried that link, leads to an emty page.

Link works for me.......................

You may have security setting that is preventing your computer from opening the PDF file.

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Awesome PDF Dave, thanks, saved it here. :)

Cool Jim, glad you liked it. I got it from someone else as a Word document, then cleaned it up, added a little bit, and saved it as a PDF............

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I had this exact same problem when I first got my 69 car! I was told that it was most likely the way the tires are balanced. Got a reblance...still vibration above 50ish mph... Replaced every suspension component! Still vibration. Balanced driveline=vibration. Turns out, I had a slightly bent axle shaft! When I got the rear axle replaced, it went bye bye! These types of problems can be tough to figure out, and annoying to put up with! Good luck...
Dano:thumbsup:

Chevy SS, thanks for the link. Lots of valuable info. I too have a vibration above 50mph.

I had the same in my '69 mine ended up being the driveshaft was out of balance