Spitfire Spit driveshaft ?

[Norton47]

Can you swap out an OD transmission and install a non OD trans and use the same drive shaft on a 1975 Spitfire?

How does one tell if you need oversize circlips on the u joints?
I read somewhere that if the new u joints are to loose that you install thicker circlips. Is this true?

 

[Andrew Mace]

Can you swap out an OD transmission and install a non OD trans and use the same drive shaft on a 1975 Spitfire?

Assuming it's a single-rail gearbox, the OD propeller shaft is about 1" shorter than the non-OD shaft. So if you have a strap-drive shaft, no go; if you have a sliding-spline shaft, it <span style="font-style: italic">might</span> work (I don't know for sure). Good news, though, is that non-OD shafts are easier to find than OD shafts!

Oh, and you'll also need a different rear gearbox mount; they are <span style="font-style: italic">not</span> interchangeable.

 

[guzzul]

How does one tell if you need oversize circlips on the u joints?
I read somewhere that if the new u joints are to loose that you install thicker circlips. Is this true?

The new u-joints should fit tight, you should not have any movement under the circlip on new u-joints.

On used (i.e. worn) u-joints I have heard of installing a shim on top of the u-joint cap as a quick fix. Cut the shim(s) out of an old coke can and install on top of the cap before the circlip goes in.

As for an oversized circlip, I would have thought the groove in the flange would not accommodate an oversized circlip. Maybe it will?

 

[DrEntropy]

ROSS!!!

Coke can?


COKE CAN?!?!?!


m'gawd.


No self-respecting LBC owner would EVER use a Coke can for shim stock!


....now a Miller or Bud can onna other hand, wellll....




:thumbsup:

 

[Norton47]

Thanks for this information.
The car is a 1975 with a single rail trans and overdrive. It appears to measure in length from the bell housing to the flange on the output shaft around 26.5 to 27 inches.
It has a strap connection at the drive shaft to differential.

The proposed replacement trans looks to be a earlier 3 rail non-overdrive unit. I will ask for a measurement.

The overdrive unit works but 1 and 2nd synchros are worn.
I am negotiating on this engine and trans. https://boise.craigslist.org/pts/830561366.html

I was hoping for a drop in and then repair the over drive unit at my leisure.
Now I don't know, sounds like I have to round up more parts.

 

[Andrew Mace]

The proposed replacement trans looks to be a earlier 3 rail non-overdrive unit. I will ask for a measurement.

Sorry, I'd meant to give you all this in my first reply.

Propeller shaft lengths:

Spitfire I - IV: 41.25"
Spitfire I - IV with Overdrive: 38"
Spitfire 1500: 38"
Spitfire 1500 with Overdrive: 37"

This from the Canley Classics "Propshaft Problems" page.

Hope that helps!

 

[Norton47]

Andrew
Thanks for the information and the Canely site.
So it sounds like if I put a 1973 1500 and a 73 3 rail transmission into a 1975 Spitfire that had a 1500 engine with an Over drive, I will need to do the following.
Find a 41.25" propshaft, to connect everything.

Does anyone know if the shift lever is in the same place as between both these types? Will the interior transmission cover still work?

Thanks

 

[Andrew Mace]

Does anyone know if the shift lever is in the same place as between both these types? Will the interior transmission cover still work?

No problem there. Only time the shift lever moved is on the GT6 gearbox, where it's further back. But installing one of those would present its own additional set of problems, so forget I even mentioned it!

 

[Trevor Triumph]

I have replaced three rail transmissions with the single rail. I had to change the fly wheel and clutch. It was not a direct replacement of transmission. The single rail tansmission has a twenty spline shaft, the three rail transmission has a ten spline shaft- maybe the other way around. It has been several years since the did the converstion on my cars, so I'm not sure of the details. I had a 74, I'm guessing, 1500 ehgine and a three rail transmission.
All years use the same u-joints, I believe.
Be sure to measure the flanges of the three rail and single rail transmissions, there may be a difference in the size of the flange from the transmission to the drive shaft and the drive shaft to differential.
Yes, the gear change lever in in the same place so the transmission cover will work.

T.T.

 

[Andrew Mace]

I have replaced three rail transmissions with the single rail. I had to change the fly wheel and clutch. It was not a direct replacement of transmission. The single rail tansmission has a twenty spline shaft, the three rail transmission has a ten spline shaft- maybe the other way around.

Correct, and thanks for pointing that out after I'd forgotten to; my apologies! Changing the clutch driven disc WILL be necessary.

Be sure to measure the flanges of the three rail and single rail transmissions, there may be a difference in the size of the flange from the transmission to the drive shaft and the drive shaft to differential.

So long as the three-rail is an all-synchro (usually FH in gearboxes found in Spitfires, although one might occasionally encounter, say, a "DG" gearbox from a Toledo), this will have the larger output flange.

 

[Norton47]

Thanks for all the info, fella's. But I think I will replace the syncro's in the original transmission. I have found another fellow Triumph guy that rebuilds these and he will do it for me for a reasonable amount plus parts. Any one know the best place to buy syncho's. Seems I had read that there are several cheap copies out there. I see Rimmer brothers has a kit. Has anyone done sychro's lately and had them not work out and need to be redone?
Thanks