MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG TD TF 1500 - Scuttle Shake/Drive Shaft

Approximately between 3400 rpm and 3800 rpm running around 65 mph, I periodically get scuttle shake. I used a dial micrometer checking the drive shaft and found on both ends the shaft are 012 out by the weld on the same side front and back, the center is measuring 025 out also on the same side, other side being 0. Never dealt with such small diameter drive shafts. There also seems to be a little side movement on the spline where it goes into the front yoke. What do you think, replace it or that's not enough to worry about? PJ
Paul161

PJ
In the hot rod world, there are numerous firms that do custom drive shafts and can true and balance existing shafts. They can work to tolerances far in excess of anything needed for our little "T" cars.


Regards,

Jim haskins 1953 TD
J M Haskins

I would normally attribute scuttle shake to the wheels and tyres, but I could be wrong.

Matthew.
M Magilton

DITTO on Matts comment. Your drive shaft doesnt' seem to be out that bad,, Plus, at 60-65, I believe a drive shaft out of ballance would be more like a vibration due to its higher rotation speed, rather than a shake that would be from wheels and tires.


Steve
Steve Wincze

Thanks fellas, I was leaning along those lines also. Soon as I find a shop that does it, I'm going to have the tires shaved for roundness and re balanced. I had that done on our 72 MGB and the difference was amazing. PJ
Paul161

My TF was missing the connecting bar between the fenders. The vibration was nasty at times. Installed one and the vibration is mostly gone. I believe there is a natural frequency that gets excited around 55 MPH where all the fender sheet metal is connected, I have 155 tires I think 165's would move the natural frequency up to 60 MPH plus. Those fenders are a lot of mass flapping around if not secured correctly.
Peter Dahlquist

Paul
I live in a rather rural area, but I found a local "drive line" shop who cleaned, painted and balanced my drive shaft. He also installed the new U joints. All for $30.
I suspect you can find such a shop in your area.
Unfortunately, that action did not take care of my shuttle shake. The FINAL action that completely took away my shake was restoring the car! After I reassembled the TF post painting, the shake was gone. But....I spent many an hour on other actions to try to rectify that damned shake.

Tom
T Norby

Tom, I've come to the conclusion it's the tires, reason I'm going to have them shaved.
Peter, thanks for the heads up, but my fenders are very secure with the factory brace. The only thing loose on my car is me! LOL.
Paul161

Paul,
Reciently you dropped the pressure in your tires,,, did you notice that this made the shake problem worse ??

Steve
Steve Wincze

Steve, no better! Less shake when it started. It only shakes now periodically around 60 to 65 mph, but not all the time. I checked the tires and they are approximately 1/8th inch out of round, likely poor molding process. Their Freestones, should have bought Veredesteins. If they don't true up with shaving that's what Ill do. Nice tire if you don't drive over 60. PJ
Paul161

Just a little more food for thought. I used to study vibration in the lab. The goal was to design around/avoid natural frequency (Fn) of equipment. When I was experiencing the frequency of the "shake" in my TF I was guessing at 12 to 15 Hz.

I have fairly new Vredistein 155-15's. Taking the circumference over time and distance I found approx 14 revolutions per second. Right at the frequency I was guessing. Amplitude might be 1/4" at the scuttle. Again an observation not measured. The 14 rev's per second number is pretty close to the shake or Fn. Could be just a coincidence.

Natural frequency once entered is a freaky thing. Very powerful.There is a driving force from the tires/road thru the suspension to the frame and everything else attached to that frame. There is a lot of stuff that could be excited.

The driving frequency at my wheels of 14 Hz is a gut feeling based on past experience.

I don't know the revs of the drive shaft at 60 MPH. But I would guess the vibration would be in a higher range than 14Hz (maybe 25 to 30Hz and a small amplitude as Paul noted). Doesn't sound like much but hitting Fn really can do a lot of damage.

Just thinking again. And I overthink stuff.

Peter Dahlquist

Well, I'll more than likely have 5 165R-15s for sale cheap. Their a nice riding tire as long as the speed is 60 mph or under. They have abut 200 miles on them.
I think I'm going to put a set of Vredestein Sprints on it, haven't decided yet. PJ
Paul161

Have you checked the balance of the brake drums themselves. I have run into a few that were realy bad.
Sandy
st

Sandy, the low mileage car sat for over 20 years in a dry environment and when pulling everything apart the drums looked near perfect, hardly any wear visible. I had the wheels with the tires mounted balanced to "0" on a computerized machine. I seems like all 5 tires has a slight high spot about 8 inches long and at 60 + mph we believe that's causing the problem. 400 miles to the nearest shaving service, so I decided to put Vredesteins on it as I had them before on the 72 B with no issues. Up to 60+ these tires ride great. Front shocks rebuilt by Peter Caldwell and a very tight front end, little too tight for my liking, but better tight than loose. PJ
Paul161

That is the main reason that I returned my Firestone F 560s,, out of round and could not be balanced properly,, made by a BIG company that makes and sells vintage tires.

Steve
Steve Wincze

When I bought these tires (5) one had a pin hole in the side wall, sent it back to Summit and a replacement was sent. I never noticed to now, but the tire they sent back was made in Mexico. Rotating these tires to get the best two on the front, I found that the Mexico tire is as near perfect in roundness as any could be, no high spots! The others were made in the Ukraine, no more tires made in the Ukraine for me! I also found out later that Vredesteins are now made in India! 10 years ago I ordered them directly from the factory in Holland and they were perfect, now??? PJ
Paul161

I purchases a set of 5 Vredestein's three weeks ago. They were made in Holland and balanced out just fine. They were inexpensive and look correct on my TF. Regards John
JR Mahone

Paul,

Vredestein is a Dutch company with production facilities in Holland. John is right: the Sprint Classics are made in Holland in the town of Enschede. These are excellent tires with the perfect looks for our cars.

That said, Vredestein is a member of the Apollo Tyres Ltd group of companies, based in India.

Jasper
JL Nederhoed

The shake is gone. Last two tires rotated did the trick. 55/65/70 mph gives no shake at all. 20 miles on the Interstate and 16 miles on a secondary road produced a smooth even ride with 24 lbs air pressure and no hint of a shake. If the shake comes back in the future, these tires are history. Took a while but for now all's well. PJ
Paul161

This thread was discussed between 28/06/2016 and 07/07/2016

MG TD TF 1500 index

This thread is from the archives. Join the live MG TD TF 1500 BBS now