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Late spec gear box: request for data


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I'm hoping someone will have a late-spec gearbox (J-type) in pieces somewhere?

I'd like to know the number of teeth on both the 1st motion shaft (219126) and the constant pinion gear (159621).

Reason: Trying to assemble a late-spec gearbox from the remains of a supposed (and incomplete) Dolomite Sprint box and other accumulated parts (including an unidentified TR6 1st motion shaft). The supposed Sprint box has no I/D stamped on the casing so may well be Mk2 T2000. 

Thought I had the correct late type 1st motion and constant pinion but now, having counted the teeth (23 and 35 respectively), I'm sure it is the earlier gear set, (esp as the helix angle seems to closer to 40 degrees than 35). I would like to confirm with someone who has the knowledge,  that the ratio change in the post '73 gearboxes was brought about by changing the numbers of teeth on these two gears as well altering the 1st gear set.  

Secondly, is there any way of telling the difference between TR6 input/1st motion shafts 216044 and 216871? I have read the Triumph tech bulletins about the changes in these two gears and there are references to changes in the bore depth for the nose bearing. Unfortunately, no actual dimensions.

I look forward to hearing from anyone on this rather vexing topic!

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1 hour ago, bob buzzard said:

I'm hoping someone will have a late-spec gearbox (J-type) in pieces somewhere?

I'd like to know the number of teeth on both the 1st motion shaft (219126) and the constant pinion gear (159621).

Reason: Trying to assemble a late-spec gearbox from the remains of a supposed (and incomplete) Dolomite Sprint box and other accumulated parts (including an unidentified TR6 1st motion shaft). The supposed Sprint box has no I/D stamped on the casing so may well be Mk2 T2000. 

Thought I had the correct late type 1st motion and constant pinion but now, having counted the teeth (23 and 35 respectively), I'm sure it is the earlier gear set, (esp as the helix angle seems to closer to 40 degrees than 35). I would like to confirm with someone who has the knowledge,  that the ratio change in the post '73 gearboxes was brought about by changing the numbers of teeth on these two gears as well altering the 1st gear set.  

Secondly, is there any way of telling the difference between TR6 input/1st motion shafts 216044 and 216871? I have read the Triumph tech bulletins about the changes in these two gears and there are references to changes in the bore depth for the nose bearing. Unfortunately, no actual dimensions.

I look forward to hearing from anyone on this rather vexing topic!

Hi Bob!

Speak to Peter at ORS who re-con's  Triumph gearboxes and has about 30 Triumph gearboxes on his shelves and modifies early gearboxes to later spec. i.e. 3 needle roller bearings on lay gear and using Sprint first gear etc. Tel.0114 2482632 that will save you a lot of aggro and time. He sorted me out!!!

Bruce.

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Bob,  see abstract below from Service Information Vol 1 issues 15 and 17. This gives some info on part numbers affected by the change from the 40 to 35 degrees and the number of teeth on the first speed ratio changes. Hope this helps, there is nothing on the Sprint gearbox unfortunately.

cheers

Derek 

 

Gearbox.JPG

Edited by saffrontr
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Bruce - thanks very much for the helpful reply and the contact number. I'll probably have to get a professional involved at some point and the recommendation is welcome.

Derek - thanks for the tech bulletin - I am aware of this change to first gear but was wondering if the change in 1st motion shaft and constant pinion helix angle at gearbox numbers CD51162 also involved a change in tooth numbers as there seems no other explanation for the fact that the ratios changed for 1st, 2nd and 3rd gears at this time

Do you have access to a full set of the gear-box sheets as I'd love to read more - its just for my own understanding.

 

 

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Bob,

The only reference to a change in tooth numbers that I can find is as noted in item 67 in the attachment above. With regards to gearbox sheets there aren't many in the service information sheets, there are a few US ones, namely no 1-D-7 which makes reference to the increase in bore of the countershaft gear 1st and reverse , part 128107, to enable a backing washer to be inserted before fitting of the needle bearing however this is dated April 1970 so is long time before the major changes to helix angles and ratios at CD51162. Sheet 1-D-10 is to do with the lengthening of the gearbox main-shaft  spigot at CD21769. Sheet 1-D-11 refers to the replacement of thinned dog teeth on 1st, 2nd, 3rd and top with tapered dog teeth at gearbox CD20282, Other sheets are 73-D-1 to do with a gearbox thrust washer change at CC85563, 73-D-3A covers the change to 35 degree helix as per above attachment,  73-D-5 covers the change to first gear ratio as per above attachment, 75-D-2 covers gearbox modifications to second speed gear main-shaft and main-shaft bush .

If you want copies please send me a PM with your email address and I will sort out a scan of the sheets.

cheers

Derek

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17 hours ago, bob buzzard said:

Bruce - thanks very much for the helpful reply and the contact number. I'll probably have to get a professional involved at some point and the recommendation is welcome.

Derek - thanks for the tech bulletin - I am aware of this change to first gear but was wondering if the change in 1st motion shaft and constant pinion helix angle at gearbox numbers CD51162 also involved a change in tooth numbers as there seems no other explanation for the fact that the ratios changed for 1st, 2nd and 3rd gears at this time

Do you have access to a full set of the gear-box sheets as I'd love to read more - its just for my own understanding.

 

 

Bob,

A point that I missed off is that the post 73 gearboxes seem to became a highbred from the Stag box, with out doubt the Stag gearbox would be the best option for a TR 6. I had the 3 needle bearing mod for the lay gear done by ORS but beware there are soft lay shafts out in the market. I caught Moss out on this with the file test! and they had over 40 soft ones in stock and had sold over 40 from this batch. People in Essex seem to has suffered the most from this plague of soft lay shafts with early gearbox failures. It even caught out the gearbox guru, as a friend of mine found out when he had a gearbox rebuilt by him! It did not do even 500 miles, before the whine set in?

Bruce.

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Gentlemen, thanks again for the replies.

Bruce - Good advice. I have a new MOSS lay shaft in stock and will certainly now be testing it. I expect to go to ORS for a replacement O/D for my project and I believe they have their own supplier of layshafts (?) so will think on that one.

Derek - many thanks for the offer of reprints - I have some of them from a US web-source but would be interested in those six mentioned from sheet1 - D-10 onwards.

I'll send my e-mail shortly.

 

Rob

 

 

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1 hour ago, bob buzzard said:

HiGentlemen, thanks again for the replies.

Bruce - Good advice. I have a new MOSS lay shaft in stock and will certainly now be testing it. I expect to go to ORS for a replacement O/D for my project and I believe they have their own supplier of layshafts (?) so will think on that one.

Derek - many thanks for the offer of reprints - I have some of them from a US web-source but would be interested in those six mentioned from sheet1 - D-10 onwards.

I'll send my e-mail shortly.

 

Rob

 

 

Hi Rob,

I was lead to believe that ORS  make there own? If you have access to a Rockwell hardness testing m/c. Test the Moss shaft it s/b at least 50 Rockwell on the C scale?

Bruce.

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