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MG TD TF 1500 - Gearbox weakness

Hi guys,

It seems that some lay-gears are weaker than others. The IMAGE shows four lay-gears. The two top ones have broken teeth near the holes drilled by the factory. The bottom right one has the holes drilled (wisely) well away from the teeth. The bottom left one has not broken despite having the weaker drilling. A currentent Y-Type thread shows another lay-gear with broken teeth by TWO of the holes.

My questions are:
How common is the problem ... how many other T-Typers have had similar tooth breakages near the holes?
What proportion of lay-gears have the offending hole placement?
Was it a problem fixed later in production (or vice-versa)?

Bob Schapel

R L Schapel

G/day Bob

Are the gears all out of the same model T series? Is this where the TC box differs to the TD/TF units?
G Evans

The gears in the image are all TD/TF/Y-type. (They are all the same.) The TC gearbox is much bigger and stronger. All the TC lay-gears I have seen have similar holes but they are drilled safely, well back from the teeth. If I get a chance I will post a photo of a TC gear alongside of a TD/TF gear.

Bob
R L Schapel

Bob

Many thanks for providing those answers.
G Evans

This is from my TF Feb 1954.

Peter Dahlquist

Hi Guys.
To answer G Evans' question, SEE IMAGE, which shows why the TC box is so strong. I also got out the scales. A TF lay-gear weighs 400 grams. A TC lay-gear weighs 600 grams. Note that the TD/TF box is not weak. They are great as long as they are not worn (and don't have the offending holes near the teeth). The size and strength of the TC box was overkill .... but after 70 years, long hard mileage and much thrashing, TC owners are very thankful for that.

Peter, Thanks for that feedback .... That is the first evidence that the later TD/TF lay-gears did not have the weakness.

Bob Schapel

R L Schapel

Thanks Bob you have re confirmed my confidence as to why a PO installed a TC gearbox in my TF, there is nothing to match scientific evidence.
G Evans

This thread was discussed between 27/06/2016 and 29/06/2016

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