D-type overdrive onto 1500 Spitfire??

[molten]

BIG Hello to all members.
Just registered with the forum and in need of some technical advice.

I have just picked up a overdrive g/box for 1500 spitfire. and now realise I should have done more research before purchasing (cheaply).Admittedly, not knowing a great deal about compatible overdrive boxes, when I got it home and checked it out, it turns out to be a d-type with j-type gear lever, which must have been bolted on years ago.
Suffice to say that I now understand that the box is a 3-rail box, with wrong gear lever attached.

So my question is, can this d-type box be fitted converted to fit 1500 engine?
I noted that the main shaft spline on the box differs from the single rail (non overdrive) box that is currently in the 1500, which seems to be the first problem.

Any help or advice would be very welcome.
Many Thanks

[Clive]

It will bolt up and be fine. In fact it uses the same length propshaft as your current 1500 non-od box, so that may be a help.
It is just the cap for the switch which will be different, the gearsticks are very different and do not swap. I suspect the correct caps are available from canleys and elsewhere.
There is also a "conversion" clutch plate. I know that some retailers sell them, and I "think" they are from a morris minor/midget, but I am sure somebody will have better details. You may be able to pick one up cheap off the fleabay as long as you know exactly which one you need.

The d type is not as strong as the J type, but as it was fitted to GT6's etc it won't be worried by the 1500. Downside is that you will need a relay in teh switch circuit as the d-type use a large current to kick in (drops back soon after, but relay IS needed) Follow wiring from mkIV spit.

Hope that helps a bit, and welcome to the forum!

Clive

[molten]

Hello Clive
Thanks very much for taking time to provide some advice. Thanks for info regarding the inclusion of the relay.
Does the mk 1v wiring diagram include relay?
Just one other question regarding main shaft: it has less (wider) slines on than original non-o/d. Any suggestions as to how to overcome this?

If any others have any thought on this, please post as I am greatful of any thoughts, good or bad.

Many Thanks
Scott

[Clive]

the earlier type gearboxes have the coarse splines, hence the need for the clutch plate swap ;) (ie same size plate but for the coarse splines, gcp103 http://www.canleyclassics.com/searchforapart/?desc=clutch+plate&ptno=  )
Yes the mkIV spit (and all earlier spits) include a relay in the circuit.

[molten]

cliftyhanger wrote:

the earlier type gearboxes have the coarse splines, hence the need for the clutch plate swap ;) (ie same size plate but for the coarse splines, gcp103 http://www.canleyclassics.com/searchforapart/?desc=clutch+plate&ptno=  )
Yes the mkIV spit (and all earlier spits) include a relay in the circuit.

Thanks Clive.
Understood

[beefertoo]

i dont know the price or availibility of ''conversion'' clutch plates but at worst case you could swap the flywheel as well to a 1300 early. mk1v herald etc.

if you go this way the bolt holes need opening out a touch.

craig

[molten]

Thanks Craig
I was thinking that the flywheel would also need to be matched to g/box spline too as well as the older type clutch plate.
Thanks for the tip. Looks like more scouring on fleabay then.
Cheers gents. Great forum

Scott

[marktheherald]

I run a 3 rail gearbox with D type o/d mated to a 1500 Spit engine in my Herald. No mods to flywheel. Just as Clive says, purchase the correct clutch plate and fit it right in. As I recall, the spigot bush is the same.  And yes, use a relay.

[molten]

Excellent. I know where I need to go now. Thanks fella's

[beefertoo]

if you get stuck for one and are near blackpool i've just removed an engine from my herald which may have a sutible flywheel and clutch on it.
condition unknown as i've never heard it running

craig