Roadster Rebuild Diary from Cornwall

[dcunn]

Re: Roadster Rebuild Diary from Cornwall

Good job with the box - the rest of the car ain't so bad either !

[meverett]

Re: Roadster Rebuild Diary from Cornwall

With a donor gearbox purchased for a bargain £10 from eBay and a trip to Exeter to collect and I have got the gearbox rebuilt.
Swapped the reverse gear, idler and laygear, new seals and gaskets and not forgetting the copper washer in the bell housing. Bit of paint and should be good to go. Selects gears nicely so must have gone back together correctly.

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[meverett]

Re: Roadster Rebuild Diary from Cornwall

Been pottering around in the garage and got my brake and clutch mounted in the bulkhead.
Made an aluminium reinforcing bracket. Will add some angle aluminium inside the bulkhead when I acquire some.
Also rubbed down and sprayed my standard shocks. Added the adjustable tie rods the other day.

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[b_caswell]

Re: Roadster Rebuild Diary from Cornwall

Note the 1300 box has a different size clutch splines to the 1800 box on the input shaft.

[milliemarlin]

Re: Roadster Rebuild Diary from Cornwall

Thanks Paul, do you think my reverse gear and idler have a few more miles left in them? The wear is only on a few teeth and only on the edges so teeth are still there. Cheers,

That’s the million dollar question. I can’t possibly say from just looking at the photo. As said it looks as though someone has tried to ram it into reverse while travelling forward. Could reverse be confused with 5th in a momentary lapse of reason?

Looking at the photo the wear seems to indicate that the damaged parts of the teeth are not in contact when the reverse is fully engaged so it would probably outlast the car. But if it doesn’t it is quite a faff to replace and it could damage the rest of the gearbox. It also looks as though it could impede engagement.

As a cautious chap I would tend to replace it and set my mind at rest.
Paul

[meverett]

Re: Roadster Rebuild Diary from Cornwall

Thanks for the replies guys, I have got a lead on 3 used marina gearboxes in my local area that could be potential for spares so I will check them out and follow up on this (take the top off each to check the teeth) May be a few spares for someone else when needed.

[droverpete]

Re: Roadster Rebuild Diary from Cornwall

Spitfire - Dolomite - Marina. Most of the internals are interchangeable. I used the Dolomite main shaft in the Marina box to allow its overdrive to fit on the back. Seem to remember making one good box out of three. Still got a box of bits somewhere, if there are any reverse gears there you're welcome to them.
PeterH

[b_caswell]

Re: Roadster Rebuild Diary from Cornwall

The problem that the wear will cause is the gear to possibly throw out under load.

The only difference in the Spitfire and smaller Dolomite's single rail boxes is they have a shorter input/first motion shaft than the Ital/marina. Possibly different clutch spines.

[meverett]

Re: Roadster Rebuild Diary from Cornwall

Thanks Paul, do you think my reverse gear and idler have a few more miles left in them? The wear is only on a few teeth and only on the edges so teeth are still there. Cheers,

[milliemarlin]

Re: Roadster Rebuild Diary from Cornwall

Gears are usually case hardened; adding carbon into the surface layer while retaining a tougher core. I wonder if the reverse gears are not hardened. They are unlikely to wear out.
Paul

[meverett]

Re: Roadster Rebuild Diary from Cornwall

Same item I am looking at other than I got the ital gearbox and viewing the ital kit, presume they are the same anyway.
The cage roller looks in good condition with no flat spots and smooth running but the kit has one of those as well.
The wear on the reverse gear and idler is in one place and not on all teeth so probably someone forcing into reverse before coming to a stand still.

[b_caswell]

Re: Roadster Rebuild Diary from Cornwall

Probably the same thing don't know the company.... eBay item110998945450

My sons Triumph box had the same problem but we got away with just replacing the idler. Not sure why this happens except for trying to engage reverse too soon.

[meverett]

Re: Roadster Rebuild Diary from Cornwall

Thanks Ben, I am considering a rebuild kit on eBay at £90. Includes all the bearings, gaskets, oil seals, springs and new layshaft.
Will still need the reverse gears though, is the reverse gear a known common problem or is it just mine.

[b_caswell]

Re: Roadster Rebuild Diary from Cornwall

Yes the lay gear should have 25 needle rollers each end not sure the Marina single rail box internals are identical to a later Spitfire single rail box or not. TD Fitchetts do most spares for the Triumphs but you will need to count the teeth on the gears. Stripping the mainshaft make sure you note which order and which way round the hubs go.

The front circlip on the mainshaft is a challenge and you must use a new replacement clip.

Unless the old needle rollers broke up and came out in the oil as sludge I think you are right and someone has been there before you.

What was the cage roller on the nose of the mainshaft like? worth replacing while its apart.

[meverett]

Re: Roadster Rebuild Diary from Cornwall

Looks like I am missing another 2 needle rollers for the layshaft, I got 24 for each side but think there should be 25 each side.
Where did these go, nothing else fell out of the casing.
I think this gearbox has been apart before as silicone was used on top of the old gaskets and of coarse the needle rollers in the bottom of the casing.