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Parts book - OD mainshaft part number?

H One-Twenty

H One-Twenty

Donation Time
Can anyone out there provide me with the part numbers for the mainshaft and layshaft for the all synchro OD trans?

I have a cunning plan.. so I'd like to do some number checking to see if it might work!

Cheers,
Stuart
 
dmich2

dmich2

Donation Time
Stuart. I'm not familiar with the 'layshaft', but my referenece says the parts number for SII onward is #5220633 and they call it the 'propellor' shaft. Hope this helps.


Dennis
 
alpine_64

alpine_64

Donation Time
Stuart,

This for the D type or J type OD unit, i notice you have H120 as part of your tag.. the later slant engines ran a different OD unit and shaft to the "series" alpines
 
H One-Twenty

H One-Twenty

Donation Time
Thanks. As you guessed I'd like to build myself an overdrive trans for my SIV Alpine out of the various bits of 'fastback' rapier I have lying around.

I have stripped an OD transmission from a later 'slant engine' rapier, I have also stripped a trans from a non-OD 'series' Alpine. From what I see it looks like the longer (OD) mainshaft and cluster along with the layshaft cluster from the later transmission would fit the earlier 'series' casing. I would of course need to retain the earlier (shorter) 'series' primary shaft compete with 4th gear. I can see no reason why it wouldn't all fit together.

I am curious as to whether the part numbers for the 'series' mainshaft and layshafts and the part numbers I have for the later parts (mainshaft 1236724, layshaft cluster 1224510) tie up?

I know I'd need to make up a suitable (shorter) prop shaft to suit the fine splines of the output shaft of the younger rapier overdrive unit I intend to use.

Maybe someone out there has already attempted to do this... if so, did it work?

Staurt
 
65beam

65beam

Donation Time
od mainshaft

i have also been told by a sunbeam owner and long time sunbeam expert that he can put the overdrive unit that was in one of my harringtons onto the tail shaft of my 69 alpine gt.i guess the tail shaft on the 69 trans is the same length as the od tail shaft of the earlier alpine roadsters.
 
Wombat

Wombat

Donation Time
I have pulled both the Arrow range and the Alpine (non-overdrive) gearboxes apart. The insides are very similar. The gear ratios for the Hilman Hunter (OZ version) and the Series IV all synchro are the same. I seem to. The ratios in the fastback Rapier were different to the Hunter. This was achieved (I believe) by having a different number of teeth on the gear on the input shaft and on the front gear on the layshaft that it meshed with.

So I do not think the layshafts will interchange.

There is also a difference in the mainshafts. On the Series IV, the splines that the synchro hubs press on to are coarse (10 splines IIRC) and in the Arrow range they are finer (25???).

I was thinking along the same lines as you. My plan was to use the Arrow range mainshaft and synchro hubs, the Series IV gearset and the Arrow range overdrive and adapter - But here in Au overdrive Arrow range cars are even rarer than Alpine overdrives.
 
H One-Twenty

H One-Twenty

Donation Time
Thanks Guys,

Later 'Arrow range' OD transmissions in good condition are pretty easy and cheap to get a hold of in the UK, mostly because Arrow series cars were/are pretty rot prone. The tinwork of many decomposed long before they covered enough miles to wear out the running gear.

I plan to swap the entire mainshaft, complete with all gears, synchros etc. from the later trans into the Alpine casing. I’ll also use the later layshaft cluster. The only original moving parts I plan to use from the Alpine trans are the input shaft, reverse gear and the selector forks.

I’m pretty sure it would be more straightforward to swap the input shaft from the Alpine trans into the ‘Arrow’ trans. Then just switch the bellhousings over and you’re done. However, for me, it’s easier (and a lot cheaper) to bring just the overdrive unit and gearsets back to CA with me rather than an entire transmission. I already have all the parts so I guess I may as well give it a go.

Incidentally, I hope to use the close ratio gearset from a (Holbay engined) Rapier H120 along with the 'heavy duty' overdrive unit. I managed to salvage the relay, solenoid, wiring loom and switch from the same car.
 
alpine_64

alpine_64

Donation Time
IIRC Paul Norton had installed the whole later series OD box in his S2, apparently not as much trouble as it sounds pulling and cutting and shutting a few 'boxes together.
 
husky drvr

husky drvr

Platinum Level Sponsor
alpine_64 said:
IIRC Paul Norton had installed the whole later series OD box in his S2, apparently not as much trouble as it sounds pulling and cutting and shutting a few 'boxes together.
Click to expand...


Michael,

IIRC, Paul Norton did simply switch to the shorter early all-synch input shaft in the later gearbox and installed the entire gearbox/OD unit with the early bellhousing.


Stuart,

I am not certain, but I think that there is an incompatibility to switching parts due to the differences in the reversing gears even if the inputs were compatible.

Good luck with your project,
 
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