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MG Midget and Sprite Technical - Spitfire gearbox

Someone has a midget 1500 with a broken gearbox. Will a 1500 Spitfire gearbox fit. Would it be a straight swap or if not can it be adapted to fit.
Anyone have first hand experience.
Alan Anstead

I have a 1500 midget gearbox in the shed if it would help them out
Dave Pratt

Thanks for the offer but the gearbox and a spare engine have been sourced but member now says there are differences and doesn't think it will fit.
I dont know 1500 Midgets and am miles away.
Alan Anstead

I cannot be 100% sure, but I think they are the same, excepting for a very slight difference in ratios in the lower gears. Physically they should fit since the overdrive box certainly does (once you have modified the body to clear the overdrive lump on the back)
Guy W

Thanks Guy.
I am awaiting an e-mail response from Steve Smith who has the overdrive conversion. He may post on here.
Alan Anstead

No problem, and good luck
Dave Pratt

mine has a spitfire gearbox fitted i think the ratios are slightly different I managed to get a reconditioned one cheap so thats why i have one fitted did not notice any change apart from no crunching now.
mark 1500 on the road Preston Lancs

Hi Alan,

Better late to this than never.

The spit gearbox is a str8 swop, except all the ones I've seen use a fine spline clutch centre plate, easily sorted.

The engines are identical exceisting the exhaust manifold, the spit uses a superior flowing twin outlet cast one. Just swop the midget one over complete with the inlet.

The thermostat housing is different as well, the coolant filler is not fitted to the triumph application, again easily swopped.

Do check the crank endfloat on the "new" engine, it's this lumps weak point.
SR Smith 1

Thanks all
It is just the Spitfire gearbox that has to be fitted the Midgets 1500 engine remains with the car. Looks like it will have to be tried.
Alan Anstead

Sounds like you have 2 choices. Either find a fine splined clutch plate, or you could swap over the input shaft from the old box, depending on suitable condition.
Guy W

There are books with this stuff in..... The gearbox chapter in the book is one of the longest...

For anyone that doesn't have the book or e-book the first thing is to note there are two distinct type of Spitfire gearboxes (single rail and three rail).
Daniel Stapleton


You have mail.

Daniel, all the 1500 spits used the BL standard single rail Marina type box. Both 1300, 1700 and 1800 with differing bellhousingsand clutch release methods.

Also fitted to the Dolomite range( except the sprint) in standard and overdrive form and the early 4 speed TR7's.

The later GT6 also used it, albeit with a differences to suit the 6 cyl engine.

Regards Steve.
SR Smith 1

Ah glad someone mentioned overdrive.
Has anyone tried anything like this or know if there's even enough space in the tunnel for it to fit, it's 14 1/2" by 6 7/8"? Must be close!
Don't know the price though...
Jeremy Tickle

Looks expensive to me Jeremy. Well - it's shiny anyway! It also looks a bit on the hefty side I think. It seems to be intended for much more powerful cars than ours.

Steve has written in the past about his conversion using the J type O/D box as used by the Spittie, GT6 and whatnot, but the single rail O/D boxes seem to be getting very rare nowadays.

Shiny = expensive, you're right Greybeard; add in when a site doesn't show prices it usually means they're not going to be cheap but at almost 2k for a Frontline 5 speed conversion...
Jeremy Tickle

This is on eBay right now. Price looks good to me as long as condition is okay. A good clean wouldn't hurt - you'd think the seller would have given it a bit of a wash as it would sell easier I imagine. Or would that make it too shiny? Haha.

I have no idea if this is adaptable to the A series. Obviously the bellhousing would have to go since the starter is on the wrong side and there'd be issues with the clutch/release/spigot bush etc. Probably propshaft splines and length too.

On the other hand plenty of people seem to have fitted Type9s without resorting to the Frontline kit - it can be done "on the cheap" if you can get the right version of the box.
To think it's not so long ago I gave away a complete 1800 Sierra in excellent nick mechanically, full MoT and all. If only I'd known.........

The Spitfire 3 rail gearbox is the early gearbox and is the one that doesn't fit. Spitfire models 1, 2, 3 & IV all had this box.

It seems the IV isn't a 1500 Spitfire and while only 1500 Spitfires had the later single rail box (fitted to the 1500 Midget) Rimmmers' cautions that export model 1500s (North American?) re-imported to the UK may have a 3 rail box.

So if in the UK check and if not the UK double check that your 1500 Spitfire box is a single rail.

The GT6 boxes have a long input shaft and closer ratio gears.
Daniel Stapleton

Thanks all for the input. Thanks to SR Smith who has been in contact and identified the gearbox as that for. 1300.
Thanks also to D.Pratt who has offered a suitable gearbox. I suppose I will be roped into assisting fitting it.
Alan Anstead

'To think it's not so long ago I gave away a complete 1800 Sierra in excellent nick mechanically, full MoT and all. If only I'd known.........' LOL.

I gave away a rusty 2CV in the non to distant past and good ones are now 5k. Hindsight what a b#ggar.
I emailed the overdrive folk this morning but have heard diddly from them so will ring instead. It looks as the unit fits between gearbox and back axle so fitting may entail gearbox tunnel bashing and propshaft shortening but we'll see.
Jeremy Tickle

This thread was discussed between 22/02/2016 and 24/02/2016

MG Midget and Sprite Technical index

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