Spitfire Spitfire Gearbox Swap - 3-Rail to Single [Parts?]

[dklawson]

I picked up a known good single rail Spitfire gearbox from my friend to replace the (worn out synchro) 3-rail box in our '72 project Spit. I'm doing minor maintenance on the box prior to fitting it and have several questions.

Haynes is the only text I have that talks about the single rail box. I didn't see any mention there of the front seal and its replacement. I Googled and found myself at Rimmer Brothers and two things they said confused/concerned me. They talk about early boxes with a scroll seal and later boxes with a shaft seal. I know once I take the bell housing off I'll know which I've got, but... can I bore out the back of the early scroll seal housing to take the later shaft seal?

Rimmer Brothers also worried me by mentioning some springs to be careful with/about when refitting the bell housing. I've only worked on the 3-Rail box before and don't remember any such issues there. Can anyone comment about what they are talking about? See:
https://www.rimmerbros.co.uk/rimmer/triumph/spitfire/singlerail
(search the page for the expression "re-fitting" to locate the "Technical Jotting" section about the bell housing and springs).

I know I'll need to buy a 20-spline friction disk for the new gearbox. I will replace the throw-out bearing while I'm there. Will I need a new pressure plate and if so, do the later pressure plates for the 20-spline disk fit the earlier flywheel that will be on my '72s 1300?

Thanks in advance for the comments and advice.

 

[trrdster2000]

Doug, are you on the forum. I have just done this and a few things will help you I'm sure. Send me a PM with your phone number and I will give you a call. I'm in Salisbury.

Wayne

 

[dklawson]

Wayne, thanks for the telephone call. I'll make sure to order the components you mentioned and I'll look very carefully at the driveshaft length.