Vibration at 50 mph

[Russ B]

I just had the U joint on my cabriolet replaced. To find the problem, we put it on a rack raised the back wheels and I put it through the gears and my mechanic listened with a stethoscope at various locations til he found the noise just behind the transmission.

I had no qualms about driving this car at 50 back in the '60's. Now it has a stronger motor and F150 trans, so I hope and expect to be doing it again once the motor has a few more miles on it. Been up there only for a couple short periods when I hopped on the Interstate.

[marc hildebrant]

Welcome to the forum.

With regard to the various answers, you will find that some members are not very helpful and like to give "smart-ass" answers. However, many here will give you good, honest replies.

Just ignore the replies that aren't helpful.

By the way, a Model A should be able to drive at speeds up to 65 MPH without excessive vibration. With today's drivers, though, I wouldn't go that fast.

Marc

[CWilson]

Originally Posted by marc hildebrant

Welcome to the forum.

With regard to the various answers, you will find that some members are not very helpful and like to give "smart-ass" answers. However, many here will give you good, honest replies.

Just ignore the replies that aren't helpful.

By the way, a Model A should be able to drive at speeds up to 65 MPH without excessive vibration. With today's drivers, though, I wouldn't go that fast.

Marc

Thanks for the welcome!

I live out in the country where our roads are mainly 45 mph, which i drive @ 35. On my way to work, I have a stretch of road about 1 mile long that is 55mph. On that stretch I drive 50 mph.

Back to the original topic, it was the muffler rattling inside the clamp. Like someone suggested, I took a wood shim and tapped it in place, then took a quick drive. No noise, or vibration. Thanks to all!

Chris

[James Rogers]

Originally Posted by CWilson

Thanks for the welcome!

I live out in the country where our roads are mainly 45 mph, which i drive @ 35. On my way to work, I have a stretch of road about 1 mile long that is 55mph. On that stretch I drive 50 mph.

Back to the original topic, it was the muffler rattling inside the clamp. Like someone suggested, I took a wood shim and tapped it in place, then took a quick drive. No noise, or vibration. Thanks to all!

Chris

Be careful with a tailpipe that is mounted solid. You can and probably will break the pipe somewhere in the system. If the pipe rattles, you have a problem somewhere else. These were designed and have been run with the pipe mounted loosely in the clamp for 85 years without problems unless something else is wrong.

Just sayin'.

[1crosscut]

Chris - glad you found the trouble. As James stated having the pipe solid in the clamp will cause troubles. I should have been more clear on my suggestion to use the wood shims only as diagnostic tool. If you do center the the pipe using 3 small wood shims and putting the three small blobs of silicone in the gaps be sure to remove the shims after the silicone has cured. Don't over do it with the silicone. You want it to be able to break one side of the bond from either the tail pipe or the clamp.

[CWilson]

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Yes, I only put the shim in there to there to diagnose! Thanks!

Chris

[CWilson]

Originally Posted by James Rogers

Be careful with a tailpipe that is mounted solid. You can and probably will break the pipe somewhere in the system. If the pipe rattles, you have a problem somewhere else. These were designed and have been run with the pipe mounted loosely in the clamp for 85 years without problems unless something else is wrong.

Just sayin'.

So you are saying that the shim was only covering up another problem? I will investigate a little more tomorrow to see if I can find what might be causing the vibration further up the line.

Chris

[Theo]

i am having the same problem with my car. The mount on my exhaust broke all together. Didnt even think that would cause something like this, ill definitely check this out.

btw i do 55-60 all day long and never have any problems.

[29spcoupe]

After reading this thread, I decided to check my exhaust. I had a bad vibration at 50 mph. I re-adjusted the exhaust and now have a slight vibration at 32 mph but goes away at 35. On deceleration it appears at 32 but goes away at 30. Great advise from this forum. Thanks, John

[CWilson]

For people using the search function.

I still noticed a little more noise and after further investigation found that the floor board was not screwed down, causing a vibration. Installed the screws, nice and solid now. All vibrations gone.

[BILL WILLIAMSON]

Originally Posted by Patrick L.

I'll assume that checked everything external around the area of the noise.

It seems as though you may have a bad u-joint.

WHOA,
How can a u-joint be condemned, with such a small amount of info?? It could be ANYTHING! Statements like this could have the owner tearing into stuff like a chicken with his head missing & to no avail, in finding the noise. "MAYBE" it's just a Model A harmonic "THING" that you learn to accept as part of the "MODEL A EXPERIENCE" Doesn't sound like anything disastrous, if he can drive "PAST" the noise.
A LOT of Model A's get noisier past 45 MPH, sometimes sounds as if you're "TEARING UP YO' MOTOR"
Chief's friend restored a high dollar Fordor & SOLD it, 'cuz it didn't go "HMMMMMMN"!
Bill W.

[steve s]

Here's what I did to isolate engine vibration from being transmitted via exhaust pipe to frame. Used a generic rubber "hanger" from auto parts storeo, plus wrapped the pipe with fiberglass cloth from the lab (asbestos should work as well).

[Chuck Sea/Tac]

I use a strip of asbestos as well. I dropped my exhaust once and it stopped the tailpipe from sliding in the clamp, which broke my exhaust manifold. Bummer

[larrys40]

Originally Posted by BILL WILLIAMSON

WHOA,
How can a u-joint be condemned, with such a small amount of info?? It could be ANYTHING! Statements like this could have the owner tearing into stuff like a chicken with his head missing & to no avail, in finding the noise. "MAYBE" it's just a Model A harmonic "THING" that you learn to accept as part of the "MODEL A EXPERIENCE" Doesn't sound like anything disastrous, if he can drive "PAST" the noise.
A LOT of Model A's get noisier past 45 MPH, sometimes sounds as if you're "TEARING UP YO' MOTOR"
Chief's friend restored a high dollar Fordor & SOLD it, 'cuz it didn't go "HMMMMMMN"!
Bill W.

Bill,
Good to hear you're back! Same thing I was thinking!!! I agree. You can't condem a U-joint based on that.

A few simple things are of course the exhaust clamps as has been covered, engine pans if you have them... as they break at the engine and vibrate tremendously.....transmission /floorboard plates, steering column, horn rod, spark throttle rods, etc. I would suggest to start checking everything for tightness... test drive and listen and feel for vibration. A certain amount is inherent in the cars anyway...

[C26Pinelake]

In my opinion this is not a car to be driven on the freeway or at freeway speeds. It is 80 plus years old and should be driven with that in mind. I am not surprised that a noise is created when you drive 50 mph and I am sure more noises will surfaces at 60 mph. I also don't think we are an accident waiting to happen when we drive 30 to 40 mph when that is the posted speed. Just my humble opinion ! Wayne

[George Miller]

The pipe needs to slide in tail pipe clamp. When the pipe heats up it will grow longer, as metal expands when it gets hot. This will in time bend the rear of the manifold down.

[Will N]

Originally Posted by 700rpm

Simple fix. Don't drive 50 mph. You're overdriving your brakes and your headlights anyway. If you want to go fast, get in your modern car.

Originally Posted by mshmodela

I agreed, 35-40mph is about what a 83 year old block should be pushed... They have only so much life left in them., heatin and cooling cycles that is...

50 MPH is a perfectly reasonable expectation from a well sorted our Model A. Ford advertised 60 MPH capability when the car came out. Of course if your brakes are such that you can't come to a sure and steady stop, you shouldn't be driving the car at any speed. And as 700rpm mentioned, of course at night you should be prudent in your speed.

As far as heating and cooling cycles go, mshmodela- it's going to heat and cool whether you go 35 mph or 50 mph, so that's not a logical arguement. If you have a good rebuilt motor that isn't shaking itself to pieces, there's no need to hold it to only 40 mph.

As for your real concern- the vibration- they all vibrate. It's just a matter of learning what is normal and what is indicating something may be out of whack. My model A's set up a harmonic vibration at a somewhat lower speed, but they smooth out over 45 mph. Your vibration zone may be at the 50 mph level. Although all of this is just speculation, as it is very hard to diagnose a vibration problem even in person, let alone over the internet!

[C26Pinelake]

Certainly worth consideration is that when Ford advertised 60 mph, every part on the car was brand new ! They certainly did not say that you will be able to drive it 60 mph when it is 85 years old. There is indeed a significant difference ! They also did not suggest that you were safe at 60 with on a freeway when you can be required to stop on a dime with miles of cars behind you, in front of you and beside you. Had they considered traffic conditions that we experience today there would have been seat belts and safety glass in every vehicle. To suggest that what Ford said 85 years ago applies today is in my opinion not rationale ! Wayne !

[Tom Wesenberg]

Because a car can go 60 or 65 MPH doesn't mean it's a good idea to go that speed, especially for any distance. My cousin in Michigan had a mint 41 Chevy 1 1/2 ton truck that her dad bought new to haul his fruit to market. 25 years ago her husband let a friend borrow it to haul some hay bales for his horses. That fool friend thought it was fine to drive on the freeway at the same speed modern cars drive. He put a rod out the side of the block, and even though I bought another block for the truck, it never got fixed. It sat behind the garage until it rusted away and went to the scap yard. What a waste of a nice truck. My 1949 1 1/2 ton Chevy truck goes down the road nice at 45 MPH, but I have driven 50 for short distances.

If I wanted to run my Model A faster than 45 I would want a counterweighted crankshaft, and a higher speed rear end or overdrive.

[C26Pinelake]

Originally Posted by Tom Wesenberg

Because a car can go 60 or 65 MPH doesn't mean it's a good idea to go that speed, especially for any distance. My cousin in Michigan had a mint 41 Chevy 1 1/2 ton truck that her dad bought new to haul his fruit to market. 25 years ago her husband let a friend borrow it to haul some hay bales for his horses. That fool friend thought it was fine to drive on the freeway at the same speed modern cars drive. He put a rod out the side of the block, and even though I bought another block for the truck, it never got fixed. It sat behind the garage until it rusted away and went to the scap yard. What a waste of a nice truck. My 1949 1 1/2 ton Chevy truck goes down the road nice at 45 MPH, but I have driven 50 for short distances.

If I wanted to run my Model A faster than 45 I would want a counterweighted crankshaft, and a higher speed rear end or overdrive.

Amen my friend !
Wayne