1966 Vibration starting at 45 MPH

[Ohjai]

I am considering a 1966 that is on Bring a trailer. It mentions a vibration starting at 45 MPH and I am wondering how big of a deal this is to remedy before I place a bid on it. I have a 38 Cadillac that had a vibration issue, it turns out the engine was not rebuilt properly, it is now in the process of complete rebuild.

Here is the comment the seller made of this 66

"It’s not a suspension issue. Tires are all balanced. The driveshaft has new u joints and has been balanced. The car has been driven about 2000 miles since my dad has owned it with no changes with the things that have been done. It is most noticeable from 45mph on up and stays the same frequency. I have gone on several trips with him without any problems."

Your comments and advise is most welcomed.

Jim

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[74 Harley]

There are many things that could cause a higher speed vibration,it could be an issue in the rear axle. It appears to be a very nice car, bid with the idea you may need to spend another 1500.00 or more on it. Good luck!

 

[Tigerone]

I am considering a 1966 that is on Bring a trailer. It mentions a vibration starting at 45 MPH and I am wondering how big of a deal this is to remedy before I place a bid on it. I have a 38 Cadillac that had a vibration issue, it turns out the engine was not rebuilt properly, it is now in the process of complete rebuild.

Here is the comment the seller made of this 66

"It’s not a suspension issue. Tires are all balanced. The driveshaft has new u joints and has been balanced. The car has been driven about 2000 miles since my dad has owned it with no changes with the things that have been done. It is most noticeable from 45mph on up and stays the same frequency. I have gone on several trips with him without any problems."

Your comments and advise is most welcomed.

Jim

I have a 66 with the same problem. Is it a 428, that seems to be common with that engine if anything has been changed on the internal part of the engine. I am about to pull mime down and go through the engine and balance it.

 

[74 Harley]

@Tigerone , have you removed the inspection cover off the trans and checked to make sure you have the proper flex plate? A 428 needs external balance weights. Front and rear.
The car in question is a 390 car.

 

[Frankie the Fink]

Its not the poster's car to diagnose; its an auction car.
It makes a difference if the vibration is a specific speed related or RPM-related vibration.
It sounds like its driveline related but could be wheels/tires...
Also U-joint alignment, bent yoke or pinion, etc could be the culprit.
Frankly, I'd never try to sell a car with a problem like this because the discount you have to offer to score a sale will far exceed the cost to repair the issue.

 

[Poppy Red]

I am considering a 1966 that is on Bring a trailer. It mentions a vibration starting at 45 MPH and I am wondering how big of a deal this is to remedy before I place a bid on it. I have a 38 Cadillac that had a vibration issue, it turns out the engine was not rebuilt properly, it is now in the process of complete rebuild.

Here is the comment the seller made of this 66

"It’s not a suspension issue. Tires are all balanced. The driveshaft has new u joints and has been balanced. The car has been driven about 2000 miles since my dad has owned it with no changes with the things that have been done. It is most noticeable from 45mph on up and stays the same frequency. I have gone on several trips with him without any problems."

Your comments and advise is most welcomed.

Jim

The above problems sound very familiar to me. I had a 66 with the 390 eng. and a vibration that started about 40MPH. Kind of a rolling drumming noise. Bought new tires had the wheels balanced, driveshaft balanced, new universal joints, springs re-sprung (a member said if the rear springs were sagging, it would mis-align the driveshaft angle), replaced the harmonic balancer, replaced the torque converter, did everything possible except re-build the engine. I believe the vibration must have been in the engine, because, with the transmission in Park, bringing the revs up to 3200 you could feel the vibration in the seat and steering wheel, and the only rotating parts were the engine and torque converter. Could not get rid of the vibration, and wasn't about to spend a further 8K$ on an engine rebuild, so sold the car.
Bought another 66, with a 428 this time and was absolutely gob-smacked when at about 45MPH, it did the same thing! The vibration is not as pronounced as the first car, but still annoying. Started the elimination process again, but have not found the problem yet. I think it is a curse Ford put on the 66's!

Anyone else reading this post with suggestions or comments please let me know!
Cheers

 

[Ohjai]

Thank you all for your comments. I just became a paying member of this club and a new owner of a 1966 Thunderbird.

1966 Ford Thunderbird Town Hardtop

Bid for the chance to own a 1966 Ford Thunderbird Town Hardtop at auction with Bring a Trailer, the home of the best vintage and classic cars online. Lot #70,069.

bringatrailer.com

 

[74 Harley]

Congratulations on the new car! I'm sure you will enjoy this car and get it sorted out soon.

 

[Ward 57]

I had a '66 landau but had to sell it because of a growing family. A wonderful road car. Plenty of power and good brakes. The interior was themed on an airplane cockpit and the rounded rear seats were so comfortable.
Other than the '57 I think the lines are the best. Enjoy your new to your piece of classic history. Great looking car.

 

[Frankie the Fink]

That is one beauty, when you compare that car to today's econoboxes, SUVs and sedans; it stands out like a stag among hounds.

 

[TropicalTBird]

Thank you all for your comments. I just became a paying member of this club and a new owner of a 1966 Thunderbird.

1966 Ford Thunderbird Town Hardtop

Bid for the chance to own a 1966 Ford Thunderbird Town Hardtop at auction with Bring a Trailer, the home of the best vintage and classic cars online. Lot #70,069.

bringatrailer.com

View attachment 21634

Looks great enjoy!