Spitfire MkIV mainshaft Spacers & Thrust Washers

[Peter Truman]

Rather than buying a Single Rail Spitfire Alloy Bell housing at considerable expense, when I had several Alloy 3 Rail units available, I've gone along the route of transferring the Spit 1500 internals into a GT6 gearbox case. Oh I'm also going down the route of a J type overdrive conversion too, so the mainshaft has been changed too (RKC767).

I've sourced all the necessary components, here in Aus, UK, USA, and Canada so it's taken a little time to assemble all the parts. A lot of washers and thrusts are NLA.

 

When I stripped down the original Single Rail box I kept the mainshaft gears spacers and thrusts in order, but my thrust washer to 2nd gear UKC934 (to 937) doesn't look like the unit shown in Rimmers, Moss or Canley gearbox diagrams. The unit shown there is a typical Thrust Washer with up to 4 thickness between 0.199in to 0.207in and appears to have raised bearing faces, but mine is a simple annulus arrangement of 0.875in ID, 1.241in OD and 0.121in thick/wide, there is also a single ball bearing BLS106 which inserts into the mainshaft at this location, my thrust washer won't go over this bearing, nor will the bearing fit into it's hole with my washer in place. Oh and my thrust washer has a groove in it where it butts up to the 1st/2nd Syncro Hub.

 

Can anyone supply a cross section of the Spit 1500 Single Rail &/or MkIV with a 3 Rail arrangement gearbox thro the mainshaft giving the relationship of all the components, all the usual suppliers show an isometric arrangement with components generally in line. 

 

One further question relates to the two spacers each side of the needle roller in the end of the input shaft ie 22G2840 and 22G2839, I'm sure I have both the latter ex USA. Can some one provide the dimensions of both but mainly 22G2840, as mine appears to be a very tight fit and before I fit it into the end of the inout shaft I don't want to get it jammed. 

 

Regards

Peter T

[Pete Lewis]

single rail stuff seems hard to find ,

i dont have a manual to cover it , must be some elsewhere

here's a link to parts expaned view  

 

http://www.scparts.co.uk/sc_en/british-cars/triumph/triumph-spitfire-mkiii-mkiv-and-1500-1967-1980/gearbox-and-overdrive/4-synchro-gearbox-inner-spitfire-1500.html

 

Pete

[Pete Lewis]

Scan0001.pdf

 

 

heres a sectional view from a Hanes manual on single rails

 

i can scan more but it will takes ages on my printer 

 

let me know 

Pete

[Peter Truman]

Thanks for that info the SC Parts clearly shows the correct style thrust washer with the cut out for the mainshaft indent ball. I incorrectly called the indent ball BLS106 it should be BL12.

I still don't understand that my old washer was only 0.121in thick whereas the correct UKC934 is 0.199 to 0.207in thick, mine is obviously incorrect as the annulus surface area is too small compared to the SC picture.

 

If this conversion works OK in my daughters Spitfire I'll then convert the spare Dolomite 1850 single rail J type overdrive box into a 3 rail case for my 68 Mk2 Vitesse. I should know all the pitfalls by then, I did/have been buying 2 of all the circlips, washers, spacers just to be safe seeing availability is an issue.

 

Regards

Peter T

[Pete Lewis]

Ive seen 3 rail and 1 rails parts all mixed up in a box i got as a slave ,, a hopeless mess of mix and match . someone spent a load of cah to make a 

completely 1/2 new gearbox   many bits do actually fit but wont work , you never know what youre unravelling

 

as a tip on (3 rail) same problem with 1 rail is the collet thrusts ,, I stand the box on end with a dummy input ( block with hole in) in a vice and 

lower the case with the mainshaft inside then tap the tail bearing down shaft and into case with gravity holding the gears and them darn collethrusts   ( the two peice thrusts)in place ,other wise every time you tap the bearing in the gears jump the collets fall out and you repeat this till you go mad

have it all vertical and gravity holds all together   you may need extra pair of hands to help with this

 

Pete  

[68vitesse]

Have a three rail gearbox with j type overdrive with a fine input shaft in my MK1 Vitesse.

The early 1850 Dolomites had a three rail gearbox, when they changed to single rail the only difference with the clutch was the friction disc.

 

Regards

 

Paul

[Pete Lewis]

Yes a good move, the 1850 with the rolled spline input shaft would also have the18mm mainshaft spigot

so life is extended

 

pete

[68vitesse]

Looking through an old Dolomite 1850 parts catalogue I am surprised how many gearbox components are common to the three and single rail gearbox particularly the early ones.

How this relates to other models gearbox I do not know.

 

Regards

 

Paul

[Pete Lewis]

the single rail was i believe a cost reduced and rationalised  sort of upgraded for use on Marina's,MG and someTriumphs ,  there are bit that are common and bits that fit but are very different , eg the 1st 2nd  sliding sleeve has different number of reverse teeth ,  and the hub is a rattling good fit on the  mainshaft splines ...it all looks similar  i kept a rogues gallery of hotch potch mix and match but its all binned now.

 

Pete

[Peter Truman]

Thanks gents I think I've worked it out. The gearbox was a single rail out of a MG Midget I believe as I purchased a gearbox/1500 engine from a MG person, I'd assumed it was equal to a Spit 1500, BUT in reality the main rail components appear to be from a Spit MkIV as the second and 3rd gear bushes are the same and have a separate 0.159 thick thrust washer between, also there was no BL12 indent ball hole/placement in the original non-overdrive shaft. The Spit 1500 single rail has different 2nd and 3rd bushes with the second a built in thrust washer, the adjustment there is via a thrust washer UKC934 against the 1st/2nd syncro hub.

With all the gears and original washers/thrusts installed the circlip TKC644 is a tight fit ie min play against thrust washer 159978 located between the 3rd/4th syncro hub and 3rd gear.

The overdrive mainshaft I purchased from the USA (cheap @ $65US) is from a Spit 1500 so has the BL12 indent ball hole.

I had assumed it was all Spit 1500 as why would a Spit MkIV single rail box be in a Midget, I can only assume this was due to 45 years of rebuilds and replacements, or did Triumph give it's poor cousins the hand me downs!

Well I'm putting it all back together in the 3 rail casing now and the final proof will be when installed in the car.

Thanks for the input & help

Peter T

(68 Vitesse Mk2)