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 - ring and pinion change

Hi All

I have an MG YB (also TC) and am in the process of changing the ring and pinion to a 4.55 ratio. About 2 years ago I purchased the new set from Moss and have now got round to fitting this in a spare TD axle to try on my YB. I apologise if this has been covered already but I am not a regular on the TD site.

My big question is to do with the pinion position. I now see that the supplied set is of Indian manufacture and is probably for their Oxford type Taxis and you may say don't start here but I am where I am. Therefore I wonder if anyone has used this set and had the same problem. In round terms the pinion head seems to be 10th too for in for a TD set and 40th too far in for an MGA set. I appreciate that I may have to assemble and use an indicator on the teeth but it would be useful to have a starting point.

I have Carl's manual which is all Moss supplied.

Any advice would be appreciated.

Regards
Brian Hough (south Wales)
B R HOUGH

I used the Moss kit (4.55:1) on my TF. I shortened the spacer and tried numerous shims in various combinations before I got the pinion in the right place.
Dave H
Dave Hill

http://www.ttalk.info/RearEndConversion.htm
There may be some help in one of the links. A few years ago, there was a more recent write up of the gear swap by the Southeast MG-T register, but I can't find it. I recall my machinist used the Moss unmarked gears and had to space/shim using marking indicator. George
George Butz III

Sorry to not have clear on getting to the SEMGTR version, George. In the Ttalk text it says:
The SouthEast MG T Register (SEMGTR) is right up there among the clubs that have done this. Don Harmer of SEMGTR has allowed me to host a copy of their write-up on the topic, where he added:

It was written up by Len Thomas of the Southeastern MG T Register.

Dick Lunney then edited it and Published it in Classic MG Magazine
See the Credits at the end of the article.

This is a modification and simplification of one of Cederstrand's procedures.
One should have Cederstrand;s booklet in hand also to aid in understanding the procedure.
This reduces the complex measurements to simply machining Item 3, MGA Components, Pinion back washer to 0.094 in on a good surface grinder.
Thus this is the only thing that requires machining. Availability of an hydraulic press helps a lot.

The article is referred to as the "Virgin Rear End Conversion".

The article is an Adobe pdf file and can be downloaded by clicking here RearEndConversion3.
The article has also been reprinted in the UK MG Car Club's Totally T-Type, Issue #30
Clicking on the text "RearEndConversion3" will open the article.

I'm just hosting their article on Ttalk. Bud.
Bud Krueger

Brian,
The 0.094" refers to a factory fitted MGA pinion and will not apply to the "Made in India" Moss pinion. My experience with "Made in India" CWP's is negative when it comes to tolerances. You will have to do as Dave has stated.
I have all the tolerances for these conversions except the 4.55 but am still in hospital and have no access to my drawings.
Regards
Declan

Declan Burns

I used Cederstrand's guide and the SEMGTR article, with lots of help and encouragement from Declan. I also replaced a couple of the bearings provided by Moss with better ones. You need lots of nuts for the pinion (5 or 6 in my case), because the torque applied to the thread is huge and will distort the thread every time you tighten to check the preload.
Dave H
Dave Hill

I advise anyone doing this conversion to make set-up bearings for test fitting.
A 25mm flap wheel in a battery drill to achieve a slide fit on old bearings. Do the same for the carrier. It makes life much easier!
Regards
Declan
Declan Burns

I used the fifth method described by Cedarstrand article. The last one in addendum B.
This method is quite straight forward and takes all tolerances into account. I think this method could fit the indian CWP.

Laurent.

LC Laurent31

Thanks all very much for your inputs.

I think I have all the articles on this subject including Carl Cederstrands manual and have a good idea of the method to use including agreeing with LC Laurent that the 5th method seems obviously the most straight forward and accurate. I have thus measured the first installation position of the 'Indian' pinion and can compare to Carl's positions for the TD and MGA. It would therefore seem that Dave's trial and error method is what I must use as no measurement exists for the Moss (Indian) device. I think by the way that for Moss to sell this without any specific data is a bit unhelpful! In view of this Declan's idea of easy fit old bearings is very good. I will do this with the carrier ones but I have no old pinion bearings as these are different from the original ones. I will next need good articles on how to interpret the die marks on the gears when I get to that point. First I think I must reduce the pinion shim to give the MGA position and take it from there. But of course if anyone has set up this Moss pinion and knows where it ended up I would love to hear from them.

Regards
Brian Hough

B R HOUGH

Brian,
I and about 6 others installed the Moss ring and pinion set in our TDs a few years ago. We set up the pinion by measurement, but have long ago forgotten what the measurements were.
I built a jig that would hold a dial gauge and which bolted to the open face of the diff. That ensured that the relative measurements were the same (knowing the relative ring gear diameters).
One word of caution, however. When setting the pinion backlash, the Moss instructions that came with the R&P set were wildly wrong. They specified a backlash that was way too tight. You may have a different set, but be forewarned.
Lew Palmer

Here is a picture of my setup. The dial indicator is (temporary) glued on a loudspeaker magnet which then goes to the head of the pinion as descibed in the fifth method.
You can also see the 0.977" gauge block which is suited for MGA pinion. Yours should be different.

Laurent.


LC Laurent31

This thread was discussed between 05/06/2018 and 07/06/2018

MG TD TF 1500 index

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