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MG TD TF 1500 - Wobbly tacho drive

I have a wobbly tacho drive.

I've isolated the problem to the length of the shoulder on the sleeve that fits inside the screw coupling (see image attached). When assembled this shoulder is long enough for it to protrude out from the coupling cheek making it impossible to tighten the clamp up against the coupling cheek.

I seem to remember seeing a drawing somewhere showing a fibre washer that fits in here but I can't remember where I saw the drawing. Perhaps its my imagination!

Can anyone confirm whether or not I have a piece missing, whether its just wear and tear or whether it was designed this way and will always flop around.

Thanks

AJ


A R Jones

AJ

I have a rubber washer that fits between the generator and the drive (like a washer on a water hose). Tightens it right up.

Dave
Dave Braun

Dave,

Thanks for responding so quickly. Is this where you fitted your washer?

Thanks

AJ


A R Jones

AJ, please post your results with the washer. Mine wobbles as well and I don't remember a washer in there.
Ed
efh Haskell

Hm, that's the problem Ed, I can't yet remember where I saw it! I'll post it if I can find it.

AJ
A R Jones

Couldn't find the drawing I thought I'd seen but this is what I thought I'd seen. The washer needs to be selected carefully so the spindle on the generator isn't fouled.

The coupling assembly is screwed on over the washer. It seems to stop the brass coupling sleeve from tilting but doesn't interfere with the smooth rotation of the shaft but I'm not sure if it will wear away and what will happen if it does.

Any comments would be welcome. I tried fitting an O ring but it compressed snagging on the shaft and it didn't turn as freely.

AJ


A R Jones

A fiber or metal washer will work, as long as it doesn't foul the rotating shaft (for many years I used a metal washer that I filed a slot into the inside diameter so it would fit past the swagged portion of the shaft that slides into the slot of the armature). 'O' rings or rubber washers will fail over time as they are softened by the oil/grease that oozes out of the tach drive gearbox. Another source of wobbling can be a worn boss on the tach gearbox that the coupling clamps onto. I had to shim the OD of the boss of the tach gearbox on our TD to stop it from rotating freely. Cheers - Dave
David DuBois

That looks like the repro generator or Lucas replacement that was available some years ago(spade terminals). The threads on some are much shorter than the originals, thus requiring a pretty thick spacer. I would stick to metal or fiber, rubber will also allow movement. Also, search the archives- there is as bunch of other info in there regarding tach drive mounting issues. It is not one of the most brilliant pieces of engineering on the car! George
George Butz

AJ _ I missed the picture first time around - the fiber washer shown in the picture is in the wrong place. It is too large and makes the problem worse by stopping the threaded collar from screwing all the way down. The washer should sit on the every end of the threaded boss on the generator such that it then tightens on the center portion of the adapter when the threaded collar is tightened all the way down. Cheers - Dave

PS that is a generator from an early midget.
David DuBois

Sorry David I'm not sure what you mean. I did a (poor) sketch of a side elevation of threaded boss to clarify the position of the washer.

Did you mean position 1 or 2 in the attached. I put mine in position 2 and the collar screws down all the way. If I put a washer in position 1 then tightening the collar causes the generator drive shaft to tend to turn the sleeve that the brass clamp fits onto. In position 2 the shaft is free to turn without turning the clamping sleeve.

I have assembled it in position 2 and it stops the drive from wobbling about and the pulley wheel is free to rotate.

Thanks

AJ


A R Jones

AJ - Going back to the second picture you sent, I have edited it with the position that the washer should rest on. The washer has to have a fairly large outside diameter so it just fits into the collar of the adapter and a small enough inside diameter to seat on the top that I show with the yellow arrow. As I remember, I used something like a fender washer that I filled a slot into the ID to accommodate the key on the shaft of the adapter. If you need more clarification, e-mail me at SUfuelpumps@donobi.net and I'll take some pictures of my set up. Cheers - Dave


David DuBois

Dave, I didn't know that was an early Midget unit. That is what Moss sold as a replacement back in the day. It was on my car for years until I rebuilt the original. I just grabbed it from my closet-it is dated 3/74, and #22744. The threads area lot shorter, which of course causes the wobble. George
George Butz

George - I should have said a Midget, rather than early Midget and it is what Moss has been selling as a replacement for the TD generator (or was until they started selling a version made in India). Yo are correct, the threaded portion of the boss is short and it is (I believe) a British Standard Brass thread, which is 20 or 26 TPI regardless of the diameter of the item being threaded. Dies are available for this thread from Uni-Thread in England http://www.uni-thread.com/ which might be a consideration for Alan as he wouldn't have to pay postage across the Atlantic. The other possibilities include using several washers or cutting the brass fitting on the adapter kit shorter. Cheers - Dave
David DuBois

In case anyone is following this thread, with the help of David D the gearbox drive is solid as a rock. Many thanks DD.

A fibre washer sits on top of the generator boss as shown in the third picture above. The coupling tightens down nicely. The generator is made in England by Lucas and is labelled 22744D 40-10-67. All I have to worry about now is whether the smoke leaks out.

Thanks

AJ


A R Jones

I see the clever extra support bracket. That should help it stay together.
George Butz

AJ
I am noticing a "steady strap", on the right of your drive , in the photo, that attaches your drive housing, to the gen. housing....Is that stock, or something that you have added....
Mine doesn't have it, but it looks like a good thing to do.
Edward
E.B. Wesson


While we are here, what type/kind/weight
of grease is used in the tach reduction greaser....?

And what type/kind/weight of oil is used
in the generator oiler....?


Many TIA.


DrRx.
drcrougeux

Alan - If the fiber washer you are using crushes down to the point where you tach drive gear box is floppy again, you will need to put a second washer on top of the existing one. I notice that in your picture there are no more threads showing below the knurled sleeve as there are on the older generators. This is what George was talking about when he commented on the boss being shorter than on the original generators. Cheers - Dave
David DuBois

Conrad,

I use lithium grease. It seems to perform well under the heat of the engine compartment. I've tried other lubricants, but they always seem to squeeze out of the crack separating the two halves of the tach gear housing.

Gord Clark
Rockburn, Qué.
Gordon A Clark


Gord.

Thank you.

What about the generator oiler....?
There is supposed to be a felt pad in there.
Do you soak it...?
If felt is missing, then what...?


DrRx.
drcrougeux

Cut a chunk of felt, or roll up a strip of craft felt and stick it in the hole with the spring.... soak it with oil/grease and your done....
gblawson(gordon- TD27667)

1 The WSM says the gearbox should be topped up with EP90 gear oil.

2 The additional support isn't my idea . See

http://www.ttalk.info/picture_this.htm#Tach Box Stabiliser

It attaches under the oil nipple and I glued a short piece of studding in one of the blank holes in the top of the geny casing.

3 WSM says to take the spring and felt out of the housing, half fill the cup with hight temp grease, I used Castrol LM, and fit it all back together.

4 Yes David it is screwed right down but it does secure the drive. I will need to keep an eye on it. If I ever get it back on the road! I didn't realise restoring an MG took your life over for such a long time.

AJ
A R Jones

http://www.ttalk.info/picture_this.htm#Tach%20Box%20Stabiliser should work better Bud
Bud Krueger (TD10855)

"I didn't realise restoring an MG took your life over for such a long time."

Like marriage - It's a lifetime commitment ;-)
Cheers - Dave
David DuBois

Yikes, what a mess. See:



Bud Krueger (TD10855)

and, thanks to John Twist:



Bud Krueger (TD10855)

This thread was discussed between 25/06/2011 and 28/06/2011

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