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3 Rail to Single Rail


Darren Groves

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Fine spline clutch (late Toledo/Dolly 1300)

Propshaft length adjustments depending on OD/non-OD. I think both are different from their 3 rail counterparts.

some messing about with the rear mount. Will depend on what you have now and whether OD or not.

Some messing about with Speedo cables and speedo gearing. Also depends on OD or not.

possibly gearstick mods. Spitty one might work as is but the Dolly ones cause knuckle to dashboard contact unless significantly shortened.

Think that's it....

Nick

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Clutch disc as its likey to be a rolled spline input shaft not a 10 cut splines   not sure but flywheel to later clutch ???

Rear mount bobins are the same , not sure about the  bracket

Is the speedo cable  connector a later design ??

Had one in a local herald 13/60  and the remote was too low ,  and  the  tunnel hole restricted gear shift  had to make a gaitor

and extend the stick length

Pete

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Sorry should have given a little more info.......It's not for my Herald, but a 1300 MKIV Spitfire project (https://photos.app.goo.gl/M3J8mU4aRLS31o9q6) that currently has a 3 rail non-OD box, I have been offered a single rail OD box. I'll get a new prop anyway, but just wondered about clutch/flywheel arrangements. So friction plate is the fine spline 1500 type, so can I use the 1300 Pressure Plate or do I need to use a 1500 Flywheel & Pressure Plate. 

Thanks

 

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You also need the single rail bell housing to accommodate the remote. The 1300 flywheel should be OK but as said a 1300 Dolomite clutch drive plate is required. The existing diaphragm cover should be OK if in good condition. 

The speedo drive will be different and is dependant on the diff ratio. All speedo's driven by the single rail set-up were 1000 turns per mile. So the cog in the gearbox was changed to suit the diff. If you are using standard wheels and standard diff then the nearest cog is 18 teeth brown in colour.

Many years ago I made up a single rail gear stick without the rubber insulator. Not a good idea as it transmitter loads of noise and vibration! So the rubber insulator is there for a good reason. Though it does look like an after thought to me. 

Dave

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33 minutes ago, dave.vitesse said:

The 1300 flywheel should be OK but as said a 1300 Dolomite clutch drive plate is required. The existing diaphragm cover should be OK if in good condition. 

Seems the Dolly 1300 Clutch Kits are pricey compared to a Spitfire 1500. Spitfire 1500 flywheels can be picked up cheaply, so would a changing the Flywheel be a simpler long term option....is it a straight swap with the 1300 Flywheel?

Darren

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4 minutes ago, dave.vitesse said:

The 1500 flywheel is a bit heavy for the 1300 and no it's not a straight swop. If I remember the flywheel to crank bolts are larger on the 1500. It can be done with spacers, but not advisable.

Dave 

How about drilling the 1300 Flywheel to accept the 1500 Pressure Plate? Think I have read that before somewhere.....

Darren

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2 hours ago, Darren Groves said:

How about drilling the 1300 Flywheel to accept the 1500 Pressure Plate? Think I have read that before somewhere.....

Darren

No. The 1500 is weirdo "pot clutch" with a raised ring on the flywheel. Using the correct 1300 clutch plate is definitely the easiest way.

Nick

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Just going with the, admittedly more expensive, Dolly 1300 clutch is by far the easiest way - it's what I have on my Mk IV Spit.

Gearbox mounts will be 'standard' (in this case standard Spitfire 1500 O/D mounting plate (TKC1407) and rubber (159656), as will the prop. (again in this case Spitfire 1500 O/D prop).

In theory you also need to trim the prop. tunnel and fit the screw-on access piece (YKC1486).  I seem to remember you can get away with just a little light trimming of the tunnel - and the access plate ends up in the wrong place and DOESN'T give you access to the prop. bolts from above anyway, so adds nothing.

Then I think it was just a 90degree angle drive and Spitfire 1500 speedo cable.

 

 

There's also another option that lets you use the 1500 clutch but I can't remember what car you needed the flywheel from.  I DO remember it was a pain because the source car had a different ring gear so you had to put a Spitfire one on.

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I replaced a 3 rail with a single rail simply   because  a good one with an overdrive became available at a price I  really could not  refuse . I had called in when  driving through Cheshire  to a placed called ‘Triumph Nuts” ( this was a few years ago, he may not be still in business)

He supplied me with the gearbox with  bell housing , the rear gearbox mounting and a correct length propshaft and a 1500 flywheel and some very  useful advice  - all in for  around £65 or thereabouts , I think.

I had to buy a 1500 clutch plate and some spacers  from Rimmers for the flywheel bolts and apart from  a remote gear change bush overhaul kit, that was about it- and a 90 degree speedo drive.

The flywheel is quite different ,as others have descibed  -I don’t recall it being  any heavier  though,and there were no issues re ring gear/ starter  - and it ran smoothly.

 

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5 hours ago, Mjit said:

There's also another option that lets you use the 1500 clutch but I can't remember what car you needed the flywheel from.  I DO remember it was a pain because the source car had a different ring gear so you had to put a Spitfire one on.

The 1500 Dolomite has a pre-engage starter and hence has different starter ring gear than the 1500 Spit. Other than that the flywheel is the same as the 1500 Spit.

The best option is to use the existing 1300 flywheel and 1300 Dolomite clutch.

Dave

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And the pre-engaged starters are like hens teeth - or at least the one that was fitted to mine (and failed) was a pain to sort. I did get one sorted but they powermaster(?) fitted a different gear to sort it out (can’t faukt the service) 

so when I swapped engine I also swapped the flywheel to keep the new starter!  

 

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  • 1 month later...

As advised above I got hold of a Dolly 1300 Clutch Plate so, that's all sorted.

I've been in the process of stripping both a single and 3 rail gearbox together, but was surprised to see such a difference in size of the input shafts. I've never worked on a single rail gearbox, but was expecting them to be the same length? Is the difference in length correct?

Darren

DSC_0105.JPG

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It was sold as a Spitfire Gearbox but removed from a Dolomite 1500....the seller supplied with a Spitfire Bellhousing & Gear lever (in a separate box) and it was only when I laid the 2 input shafts down together I spotted the difference. 

I'll go back to the seller to see if he can provide more info.

Darren

 

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Could be 1850 (or TR7 4 speed) if it's got a 1" x 23 spline (does look that big in the pic but....).  They are also longer.  But will have a different tooth count due to different ratios (same as Vitesse/GT6).

May have come to the seller with a 1500 Spit, but not I think fitted to it!

Nick

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2 minutes ago, clive said:

Darren, your worries when comparing the 2 input shafts is wholly justified. They should be the same length. Otherwise how will the bellhousing bolt to the engine?

I would be careful before committing to expensive work....

It's just as well I was stripping 2 gearboxes side by side, probably wouldn't have noticed until I came to fit it to the engine otherwise, that would have been a bugger. Everything else internally seems to be correct when compared to the 3 Rail/4 synch box I also have here, so it does look like someone has just swapped out the input shaft to make it fit something else....The gears and synchro rings should be with MP either today or tomorrow and I have explained the situation to him, so I'm sure he will provide an honest assessment of what's best to do.

Darren

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