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MG TD TF 1500 - Gearbox - layshaft parts don't fit

A friend of mine, who is an eductated master of auotomotive (JAGUAR) with good knowlegde of ,called my this morning. It is his first TD gearbox. It is possible that the preowner has altered some things so it is a little bit tricky (e.g. needle roller bearings are present).

I purchased the most parts from MOSS.

The layshaft doesn't fit. As far as I understood him the old layshaft has 15mm diameter and the part from MOSS has 14,4mm. The bolt to fix the layshaft ist 10mm longer than it needs.

He also mentioned that new layshaft, rollers and the laygear cluster won't fit.

What is the exact diameter of the layshaft?
W_Mueller

Just measured one I took out of an early TD gearbox. It is 14.43 mm measured on an um-worn section. I purchased a new one from Moss and it fit perfectly in the same gearbox.

Tim
Timothy Burchfield

Winfried,
There should be no needle roller bearings in there. Needles yes.
Regards
Declan
Declan Burns

Thank you Tim and Declan,

as supposed the (D)PO must have altered the layshaft. Following his damned ideas he had drilled the casting to 15mm. That could be repaired by some bushings.

Logicaly the spacer tube and the washer are also missing (all NCA at MOSS).

As reported by my friend the new sliding hub 3rd&4th from MOSS makes problems regarding to quality. Turning the gears feels strange.

Tomorrow I'll visit ma friend in his workshop.

I guess I'm in trouble.

W_Mueller

Winfried,
I think it is time to fit a five speed and be done with it! That gearbox is going to cost you a small fortune.
Regards
Declan
Declan Burns

Declan

I know your opinion. But driving an old car means for me to drive like our fathers did. I only use some minor improvements like your clutch rod, engine sealing, oil filter etc. I'm still looking for a solution. You know I have another gear box which is scratching after repair by H. from E. He promised to pick up that box but it is still storaged in the garage. He doesn't answer email, letter or phone. Anything wrong with him you know?



W_Mueller

Winfried,
No idea as I don't have any dealings with the man.

Regards
Declan
Declan Burns

Due to the special improvement of the PO I need the spacer and the two washers for the layshaft. MOSS is NA again.

Who can please give the dimension and an idea about the material?

W_Mueller

Winfried,
Here you go:
https://www.mgbits.com/contents/en-uk/p3666_Spacer-Layshaft-(Used).html

https://www.mgbits.com/contents/en-uk/p3667_Washer-Layshaft.html

Get new needle rollers while you are at it.

Be prepared to take out a second mortgage on your house to cover NTG's postal charges-they still haven't got their act together. I avoid them like the plague for that reason but their website and their selection is good.

Regards
Declan
Declan Burns

I'd ordered the spacer and the washers.

Is the casting for YT gear box realy the same as for the TD? I can get one too.

Is it a known problem that a new sliding hub from MOSS doesn't slide on the mainshaft? If yes - any suggestions?



W_Mueller

It seems that NTG can not find the 2 washers in their storage. Abingdon Spares are fine but shipping to D will last.

So I ask for the dimension and material again.

W_Mueller

Winfried,

Here are the dimensions you require.

Outside diameter = 22.38 mm
Inside diameter = 14.45 mm
Thickness = 3.13 mm

About the material, it is steel but seems to be hardened.

However I suggest that you buy them from Abingdon spares, even if it takes a few days more.

John




J Scragg

Thanks, John

If it is hardened steel, it is difficult. I had hoped that it would work with plain steel and a lathe.

W_Mueller

With people modifying their cars by fitting s 5 speed, you would think a used serviceable case would be easily sourced at a reasonable cost.

What day the rest of the group members who modified their cars?

Regards, Tom
tm peterson

Tom,

Saving mine "just in case". Also if car ever goes out of family for sale I still have the numbers matching original. I would imagine this is the case for many who have converted.

Jim N.
James Neel

Before detecting the famous construction of the PO I'd purchased many parts as laygear, layshaft, 2nd and 3rd gear, sliding hub, bearings, trust washers, rear case, needles, distance tubes etc.

A friend sold me a YT case.

Only the two washers are on backorder.
W_Mueller

Be careful. The diameter of the original needle rollers were 5/32 inches imperial, not 4mm metric. Your (D)PO probably fitted metric bearings and modified the gearbox and the laygear.
Barrie Jones

Barrie

yes - he modified the gear case, the laygear and the lay shaft.
W_Mueller

I found this text at

http://www.bobmccluskey.com/gearbox.shtml

For a reason I can't understand, the width of the striking dog was originally barely enough to engage with the dog-teeth while simultaneously covering the synchro balls, and you can perhaps infer that from the drawing. If there is too much tolerance in the gearbox or wear on components, there can sometimes be enough movement in the third gear to allow it to begin to disengage, and if it disengages far enough the bevel on the dogteeth will fling the sliding dog forward and make the gear lever jump violently into neutral: this is the basic reason for jumping out of third on the over-run, and the related problem of synchro balls popping out. To tend to overcome this problem, the width of the striking dog was increased by 2mm (1mm each side) from engine no 20026; if you suffer from the problem, yours is older than that, and you can overcome it by inserting a 50thou (=1.25mm) shim between the circlip behind the 2nd gear sliding hub and the bearing guard in front of the mainshaft bearing, the aim being to limit movement of the third gear by limiting the longitudinal movement of the mainshaft.

My engine is 2110.


We will go one with the old striking dog but got a new sliding hub. May the problem with non fitting parts result in this fact?
W_Mueller

This thread was discussed between 28/03/2019 and 26/04/2019

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