Vibration at about 45MPH

[CigarSmokerFella 0]

1969 /302

I get a wobble/vibration around 45MPH. It goes away after 50MPH but shows up wether I’m accelerating or not. I had the wheels balanced but that didn’t seem to do much at all. Thoughts? 

[Mach1 Driver 560]

Anything in the driveline that isn't stock?

Engine rebuilt recently? If so what balance?

How old is your harmonic balancer?

What trans?

I've heard of guys dismounting tires and checking the balance of Magnum 500s and to see if they run true. What company made yours?

The smart guys on here will have some ideas

[RPM 1,190]

To narrow the search, does it do it while only in gear at speed, or does it do it while out of gear?

Did you do any work to it prior to the vibration starting?

 

[CigarSmokerFella 0]

9 minutes ago, RPM said:

To narrow the search, does it do it while only in gear at speed, or does it do it while out of gear?

Did you do any work to it prior to the vibration starting?

 

It does it while accelerating or when slowing down without my foot on the pedal. Is this what you mean?

[Midlife 814]

Magnum 500 wheels need to be lug-centric balanced, nut hub centered.  Very few tire places have that capability.

Bad u-joint, incorrect driveshaft to tranny/rear end angles can also cause vibrations.

[RPM 1,190]

17 hours ago, CigarSmokerFella said:

It does it while accelerating or when slowing down without my foot on the pedal. Is this what you mean?

No. I'm talking about if you have you car parked in the garage and rev the engine to where it would be at 45 mph. Do you get the vibration then? This test will tell you if the vibration is from the flexplate/flywheel forward, or from the transmission back, including tires, wheels, driveshaft, rear end etc. And have you done any recent work to your car?

[bigmal 225]

As someone who was chasing a vibration for almost 7 years I learnt that for me it was multiple sources. Makes if very hard to troubleshoot. I changed lots of things, sometimes more than once, and found each of the following made and improvement.

• Full engine balance
• Rebuilt tail shaft (3 times). Each timer it was out of true.
• Bent axles
• Rear Drums badly corroded. (I know this is odd, but it made a difference)
• Pinion Angles. For me 0deg difference did not work. Had to be 2 deg down at the front of the diff. I experimented with 1, 2, 3 and 4 deg shims until I got the best results.
• I have to be very careful bolting on the Magnum 500s to ensure I tighten the nuts in sequence, a little at a time or I will get a vibration. The holes appear worn. Will be replacing.

While I still have a very minor vibration, it is almost completely gone.

[aslanefe 333]

I made centric rings and installed them on Magnum 500s so they will center from the axle hubs. They can cause vibration when they are centered only by the lugs. 

[Mach1 Driver 560]

4 hours ago, aslanefe said:

I made centric rings and installed them on Magnum 500s so they will center from the axle hubs. They can cause vibration when they are centered only by the lugs. 

something kinda like this?

[aslanefe 333]

5 hours ago, Mach1 Driver said:

something kinda like this?

Yes Terry, that is it.

[Mach1 Driver 560]

10 hours ago, aslanefe said:

Yes Terry, that is it.

I've never seen or heard of them being used on our cars but it seems like a natural.

Do you care to share the dementia, aww the dimensions, if you still have them? They must be different between drums in the rear, and discs up front. The drums appear to be hub-centric so why not the wheels.

 

[aslanefe 333]

7 hours ago, Mach1 Driver said:

I've never seen or heard of them being used on our cars but it seems like a natural.

Do you care to share the dementia, aww the dimensions, if you still have them? They must be different between drums in the rear, and discs up front. The drums appear to be hub-centric so why not the wheels.

 

It has been a while so I don’t remember the dimensions Terry. But disc and drum were the same as far as I can remember. Made the main out side diameter to fit tight inside the Magnum 500, inside diameter was slip fit to hub of the disc and rear axle. Put a lip with a bigger outside diameter so it stays in place and can’t move out (but not too thick so it won’t push the wheel out). If you have access to factory steel wheels, you can use the measurement of it’s inner diameter as the inner diameter of the ring as the factory steel wheels are hub centric.

My vibration was at higher speed (around 100 mph). 

A friend with a 69 428 Cobra Jet also had vibration with his Magnum 500s, rings got rid of it.

[bigmal 225]

13 hours ago, aslanefe said:

It has been a while so I don’t remember the dimensions Terry. But disc and drum were the same as far as I can remember. Made the main out side diameter to fit tight inside the Magnum 500, inside diameter was slip fit to hub of the disc and rear axle. Put a lip with a bigger outside diameter so it stays in place and can’t move out (but not too thick so it won’t push the wheel out). If you have access to factory steel wheels, you can use the measurement of it’s inner diameter as the inner diameter of the ring as the factory steel wheels are hub centric.

My vibration was at higher speed (around 100 mph). 

A friend with a 69 428 Cobra Jet also had vibration with his Magnum 500s, rings got rid of it.

Definitely interested in these!

[CigarSmokerFella 0]

1 minute ago, bigmal said:

Definitely interested in these!

Where can we order these

[Mach1 Driver 560]

aslanefe made them

[aslanefe 333]

Myself and my friend made them on the lathe ourselves, don’t know if they are available for sale. A machine shop (that has a lathe) can take measurements of the hubs and wheel of your car and can make them for you. The dimensions of your wheel may be different due to manufacturer of the wheel, it is best to get the dimension from your own Magnum 500.

[Mach1 Driver 560]

Did you use steel? I could do aluminum on my mini, but steel is hard going on that little machine.

[aslanefe 333]

I made a set from aluminum long time ago for a set of wheels I had. And made a set from steel for the Magnum 500s I currently have on the car.

Can't remember the alloy I used (6061 possibly) but aluminum was fine. Used whatever material I had laying around.

If you find the right size of steel tubing, you do not need to remove a lot of material (especially from the inside) and should be able to machine it on a mini lathe with small passes.

Or you can get 2 different sizes of tubing and slip and weld them before machining. That is what I had done with the Aluminum one, the lip was welded/machined.