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MG TD TF 1500 - renew or hold gear ring?

I guess the gear ring on the flywheel ist the first one.

There is wear at a segment where the starter goes into. A mate has the opinoin it was deliberated cut down.

Is it recommended to renew or ist the old stuff sufficient for the next 20 years? It's not because the costs. I suffer under the quality of new products.

W_Mueller

My vote--
Get a new one, and a new starter drive as well as it will be worn as well---
William Revit

Replace it. Think how much time and cost to replace if it wears a little more and fails.
George Butz III

I think there are two different starter drive dogs and two ring gears so make sure you get a matched pair or it will chew up again.
Ray TF 2884
Ray Lee

Thanks to all - so you estimate the remaining life time of a new (may be not the same quality as the old ring) part is better than the rest of the old one.

The gear ring has 120 teeth and the starter drive dog has 9. I have a 7 1/4" clutch. I guess I need a 10 3/8" gear ring. But I will measure the inner diameter. No one knows if the flywheel is an original.
W_Mueller

Would it be possible to turn the gear around and so get a few more years out of it? A poor man's solution sure, but just wondered if it was possible, especially for those who are time rich and cash poor? Cheers
Peter TD 5801
P Hehir

The old-time trick was to rotate the flywheel 90 degrees. Engines tend to stop in only a few positions... by rotating it you put a new bit of the ring gear in the place of the normal stop position.
Kevin McLemore

Peter, the teeth are machined asymmetrically for easier meshing with the drive gear. Bud
Bud Krueger

Peter, the ring gear is a shrink fit to the flywheel. One heats the ring and possibly cools the flywheel, the ring gear will then drop into position. When the temperatures are the same an interference fit results. It would not be possible to heat the ring alone to remove/rotate it, they are taken apart by drilling a hole through the edge of the ring gear then hitting it with a cold chisel.

I don’t think Kevin’s trick would work on a T series as there are locating dowels as well as machine screws.

Chris
C I Twidle

Thanks guys. Just a thought. I was aware of the shrink to fit approach but not the common method of removal. Cheers
Peter TD 5801
P Hehir

Chris gives the correct method of fitting and removal, but its also possible to remove in one piece by carefully tapping with a heavy hammer and brass drift.
Dave H
Dave Hill

Once ready for the new gear, I set the flywheel on a bed of dry ice, put some on top and cover with rags until I get the ring gear fairly hot, then uncover the top of the flywheel and drop the gear into position, let it set until they bond, then take it off the ice and let it return to room temperature. Only work is breaking the old one loose. PJ
PJ Jennings

I changed mine a couple of years back. Removed by cutting a slot with a hack saw to release the tension of the shrink fit.
New one put in oven on highest setting for one hour then using barbeque tongues placed hot ring onto flywheel and simply turn it when you think it is all the way down to check it is correctly in place. Then leave to cool. Worked fine for me.

The wear on my old one was similar to whet yours looks like and it was causing the starter to jamb !
Mel Pascoe

Early Porsche 911s had the ring gear shrunk onto the clutch. I believe this could be "de-shrunk" when the clutch was replaced.

Jan T
J Targosz

I've purchased a new one.

That's what it looks like in detail - what a difference.

W_Mueller

Different thickness in the ring, but I do not see the wear in that picture. What am I missing? Regards, Tom
tm peterson

Tom,
that is not 2 rings, just the lead in machining. Not as elegant as the original,
Ray TF 2884
Ray Lee


That new ring gear (stepped) is something I haven't seen before. Guess I'd be looking for an original design myself. Caution, --- Like Mel from Norfolk said cutting the old gear before removal has worked well for me. Be very careful not to damage the flange on the cast flywheel during removal because it is easily cracked. I had to replace two flywheels because someone got over energetic with a hammer and punch on them.
Richard Cameron

The gear ring came from abingdon spares - is the step critical? Is it a fault?
W_Mueller

I've purchase a new one.

That's what it looks like in detail - what a difference.

W_Mueller

I don't think that machined side is a leed in, the taller side goes towards the gearbox i believe and is the side the bendix comes at it from
happy to be wrong --I'm no t type expert
That ring gear looks wider than your original from the pics , might pay to check up and make sure it's not an MGA one
willy

http://www.mgaguru.com/mgtech/clutch/ft_101.htm
William Revit

From what I can find there are two ring gears available and two matching bendix drives
As long as you have a new bendix that's matched to your new ring I guess it will be ok , but I'd check up just to make sure
William Revit


Yes, I think its a MGA/MGB ring gear not a TD. Confirm what William said, but I wouldn't use it myself.
Richard Cameron

I believe there should be a small bevel on the side that goes to the flywheel to accomodate any small fillet from the machining of the step.
Chris
C I Twidle

I have 3 starters with the same bendix. So the ring should fit like the old one. The flywheel is in the machine shop. At the moment I have no chance to compare.

But if no one has ever seen a ring with a step for the TD it is mysterious.

The ring is embossed "CD120/10R".
W_Mueller

The Moss Europe website photo shows the same machining on their ring.
Ray TF 2884
Ray Lee

The one that I bought from B&G was of the original type with the bevelled edge. From their website, they still seem to be the same.
Dave H
Dave Hill

Hi

This a new never fitted 1950 TD ring gear, the chamfers go on the gearbox side of the flywheel.

Barry

B Bridgens

I'm not realy satiesfied - otherwise than Ray I can't see a step in the picture of MOSS Europe Part P163.

That's what AS emailed to me:

That is the correct ring gear, they all have the bevel or steeped teeth now.

I believe the bevel would go toward the engine side but your machine shop should know. The bevel is for a better engagement with the starter.

W_Mueller

Hi
The bevel goes on the gearbox side I believe as the starter dog pulls in from the gearbox side. This ring gear was bought from UK MG parts (Brown and Gammons) a month ago and still shows the same one on their site.

Barry
B Bridgens

I have never seen a ring gear with those steps in the teeth. I believe I would be asking some questions of the supplier before I installed it.

L E D LaVerne

Winfried,
My apologies, I must see an optician!

Ray
Ray Lee

Winfried,
call me.
Klaus
Klaus Harthof

The part no suggests it's the correct one but it just looks like an MGA/earlyB ring to me
Maybe they've changed the design'
Any chance of a picture of both sides of it
How does the overall thickness compare with the old one and out side diameter

If it is the correct one it fits this way round (in the pic) with that dowel at the top being a clutch dowel


http://www.mgaguru.com/mgtech/clutch/ft_101.htm
William Revit

William

does the picture show what you want to see?

There are small bends (red arrows). I guess they should help the starter to come in.

W_Mueller

If you look at the close-ups on Peter Edney's site there is no step.
https://www.mg-parts.co.uk/index.php?route=product/search&search=Ring%20gear
Regards
Declan
Declan Burns

Yes Winfried
And you are correct in that the starter bendix enters where the red arrows are so the ring gear should be fitted with that side towards the gearbox/clutch side of the flywheel
The other steps in the other end of the teeth are for no mechanical reason ,probably only to save a little weight spinning around
By the time the bendix drive gets that far engaged it probably doesn't need a full tooth if it gets that far
William Revit

I'd purchased one from MOSS and will decide.
W_Mueller

This thread was discussed between 18/11/2018 and 13/12/2018

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