Advice for a newbie

[Neil Clark]

We've got the same conversation going on the MGB forum just now.  A new member with 1963 car with no overdrive is wondering whether to change.

I had no overdrive on my B for the first three years.  4th was fine in 99% of traffic and I liked the engine noise at 70mph but agree it was "busy".  Then the box needed rebuilding.  I looked for a decent overdrive box but no decent ones showed up and there was so much to change anyway (box / box mounts / propshaft / speedo drive etc etc) that I chose the "Vitesse 5 speed" (the Mazda conversion kit, not the Triumph Vitesse version!)  It's a brand new MX5 NA box internals in a new case.  We've had a series of MX5's for road, racing and kit cars and these have been bullet proof.

The kit came with all the parts, bolt in, and it's been brilliant.  My tuned B now gives nearly 40 mpg on long runs in the new 5th vs 27mpg on the old 4th.  But the kit is now closer to £3,000.

[Bruce Raybould]

4 minutes ago, Neil Clark said:

We've got the same conversation going on the MGB forum just now.  A new member with 1963 car with no overdrive is wondering whether to change.

I had no overdrive on my B for the first three years.  4th was fine in 99% of traffic and I liked the engine noise at 70mph but agree it was "busy".  Then the box needed rebuilding.  I looked for a decent overdrive box but no decent ones showed up and there was so much to change anyway (box / box mounts / propshaft / speedo drive etc etc) that I chose the "Vitesse 5 speed" (the Mazda conversion kit, not the Triumph Vitesse version!)  It's a brand new MX5 NA box internals in a new case.  We've had a series of MX5's for road, racing and kit cars and these have been bullet proof.

The kit came with all the parts, bolt in, and it's been brilliant.  My tuned B now gives nearly 40 mpg on long runs in the new 5th vs 27mpg on the old 4th.  But the kit is now closer to £3,000.

Thanks Neil,

Much appreciated.  I did enquire of Vitesse if they made a kit for the Vitesse but they said no. Shame because I might have been tempted as I intend to keep the car and do some tours in it. The present set up makes long journeys just about out of the question.  

Thanks again. 

Bruce 

[Josef]

Edit: on looking back at the correspondence I had it was actually £1600 plus fitting!
 

To give you a rough idea Bruce I was quoted £1200 (by a specialist with a good reputation) for a drive-in-drive-out overdrive conversion for my 13/60. Couple of years back but not so many that I’d expect that figure to have changed much. Also wouldn’t be too surprised if I end up spending that much in the end on my current ‘rebuild gearboxes and swap them around between cars so the Herald ends up with overdrive’ journey… But hey, I’ll probably be more satisfied having done it myself

Edited January 26, 2022 by Josef
Correct price!

[Clive]

7 hours ago, Josef said:

To give you a rough idea Bruce I was quoted £1200 (by a specialist with a good reputation) for a drive-in-drive-out overdrive conversion for my 13/60. Couple of years back but not so many that I’d expect that figure to have changed much. Also wouldn’t be too surprised if I end up spending that much in the end on my current ‘rebuild gearboxes and swap them around between cars so the Herald ends up with overdrive’ journey… But hey, I’ll probably be more satisfied having done it myself

It seems "ubknown" (therefore assume probably knackered) bare overdrive boxes regularly fetch £500, so £1200 for a fitted/known good overdrive conversion is exceptional value. Mike Papworth was about £2k about 5 years ago for the same service on a GT6.  I would expect he would be nearer £3k now. 

 

[Bruce Raybould]

7 hours ago, Josef said:

To give you a rough idea Bruce I was quoted £1200 (by a specialist with a good reputation) for a drive-in-drive-out overdrive conversion for my 13/60. Couple of years back but not so many that I’d expect that figure to have changed much. Also wouldn’t be too surprised if I end up spending that much in the end on my current ‘rebuild gearboxes and swap them around between cars so the Herald ends up with overdrive’ journey… But hey, I’ll probably be more satisfied having done it myself

Always nice to achieve it yourself.  At the moment I haven't got the facilities or knowledge to do it myself without help from an expert. It would be good to know who quoted you if you  can remember.  I have seen a firm that advertise a kit but their reputation didn't sound too good. (Quiler I think it was)

.

[Josef]

1 hour ago, clive said:

It seems "ubknown" (therefore assume probably knackered) bare overdrive boxes regularly fetch £500, so £1200 for a fitted/known good overdrive conversion is exceptional value. Mike Papworth was about £2k about 5 years ago for the same service on a GT6.  I would expect he would be nearer £3k now. 

 

I’ve just dug back into my e-mail as on reflection it didn’t seem quite right to me either... It was actually £1600 for the parts, plus fitting on top of that. Going to edit the original post too!

[Wagger]

4 hours ago, Bruce Raybould said:

Always nice to achieve it yourself.  At the moment I haven't got the facilities or knowledge to do it myself without help from an expert. It would be good to know who quoted you if you  can remember.  I have seen a firm that advertise a kit but their reputation didn't sound too good. (Quiler I think it was)

.

The gearbox and overdrive can easily be removed from within the car. You don't need a garage. The under bonnet access allows you to unbolt all of the bell housing, Obviously, disconnect the propshaft, also from inside the car.

You only need to get under the rear to change the propshaft and (maybe) the gearbox support plate as that does not have captive nuts. It took me 8 hrs in 1974. Four more to remove it from the donor car.

An assistant is useful for the heavy bits.

There are plenty of manuals available and accessible on this club site.

[DVD3500]

I would say about 96% of all repairs can be done on a  Spitfire in any garage wide enough to get at least one door open wide enough for you to get in and out...

It is one of the things that makes the car so wonderful!

[Bruce Raybould]

One reason why I bought a Herald. My first classic car and I wanted to make it easy!

[Bruce Raybould]

1 hour ago, Wagger said:

The gearbox and overdrive can easily be removed from within the car. You don't need a garage. The under bonnet access allows you to unbolt all of the bell housing, Obviously, disconnect the propshaft, also from inside the car.

You only need to get under the rear to change the propshaft and (maybe) the gearbox support plate as that does not have captive nuts. It took me 8 hrs in 1974. Four more to remove it from the donor car.

An assistant is useful for the heavy bits.

There are plenty of manuals available and accessible on this club site.

Thanks Wagger,  all encouraging stuff.

[Colin Lindsay]

6 hours ago, clive said:

It seems "ubknown" (therefore assume probably knackered) bare overdrive boxes regularly fetch £500, so £1200 for a fitted/known good overdrive conversion is exceptional value. Mike Papworth was about £2k about 5 years ago for the same service on a GT6.  I would expect he would be nearer £3k now. 

 

I must be at the lower end of the scale.... it cost me £175 for a used single-rail O/D box from Chic Doig a few years back; I didn't like the single rail so sold it on after a few years for the same money. The man who sold me my latest Herald had also bought a 3-rail J-type O/D box from a US-spec Spitfire from him for the same money, £175, and sold it to me for the same. This one was bought around 2019. Barring a good clean and replacing of seals and gaskets, and some rewiring, it's going straight into the Herald.

[Clive]

2 minutes ago, Colin Lindsay said:

I must be at the lower end of the scale.... it cost me £175 for a used single-rail O/D box from Chic Doig a few years back; I didn't like the single rail so sold it on after a few years for the same money. The man who sold me my latest Herald had also bought a 3-rail J-type O/D box from a US-spec Spitfire from him for the same money, £175, and sold it to me for the same. This one was bought around 2019. Barring a good clean and replacing of seals and gaskets, and some rewiring, it's going straight into the Herald.

If you have any more for £175 let me know, I will buy them all! I need a retirement fund.

I had a GT6 one (with prop etc etc) checked over etc and then sold for £600 about 2 years ago, and apparantly I was told it was far too cheap...

[Josef]

I think it might be the few years back that makes all the difference. However. The mainshaft, oil pump drive, inhibitor switch mount, cam to switch the inhibitor switch (I think?) and adaptor plate are all available from Canleys at least. So for just a gearbox nobody should pay over the odds as the parts are there to fit to a non-overdrive box. I’ve not seen a separate used overdrive unit for sale for a while though so that might be a sticking point (not sure if the places that offer them on an exchange basis would be super happy to just sell outright?). 
 

My used 3 rail D type that I’m in the midst of rebuilding was £500 from Chic Doig. And the mainshaft is knackered!

[Wagger]

11 minutes ago, Josef said:

I think it might be the few years back that makes all the difference. However. The mainshaft, oil pump drive, inhibitor switch mount, cam to switch the inhibitor switch (I think?) and adaptor plate are all available from Canleys at least. So for just a gearbox nobody should pay over the odds as the parts are there to fit to a non-overdrive box. I’ve not seen a separate used overdrive unit for sale for a while though so that might be a sticking point (not sure if the places that offer them on an exchange basis would be super happy to just sell outright?). 
 

My used 3 rail D type that I’m in the midst of rebuilding was £500 from Chic Doig. And the mainshaft is knackered!

I have a 'Lonely' J type overdrive with no adapter plate. If I cannot scrounge the rest this year, it will be available. However, it is completely 'Untested' and I am trying to work out how to do that 'On the bench'.

Probably best to exchange it.

[Colin Lindsay]

6 minutes ago, Josef said:

I think it might be the few years back that makes all the difference.

Currently at least four on eBay for under £400, there are other 6-cylinder versions including a Dolomite 1850 box, although it's single-rail. You take your chance with S/H but the Dolomite 1850 version that I fitted to my GT6 lasted over twenty years and is still going.

[Josef]

3 hours ago, Wagger said:

I have a 'Lonely' J type overdrive with no adapter plate. If I cannot scrounge the rest this year, it will be available. However, it is completely 'Untested' and I am trying to work out how to do that 'On the bench'.

Probably best to exchange it.

There was a s/h adaptor plate on eBay recently for about £15, might still be there!

[Bruce Raybould]

Great  thanks. 

I will take a peek 

[johny]

18 hours ago, Neil Clark said:

We've got the same conversation going on the MGB forum just now.  A new member with 1963 car with no overdrive is wondering whether to change.

I had no overdrive on my B for the first three years.  4th was fine in 99% of traffic and I liked the engine noise at 70mph but agree it was "busy".  Then the box needed rebuilding.  I looked for a decent overdrive box but no decent ones showed up and there was so much to change anyway (box / box mounts / propshaft / speedo drive etc etc) that I chose the "Vitesse 5 speed" (the Mazda conversion kit, not the Triumph Vitesse version!)  It's a brand new MX5 NA box internals in a new case.  We've had a series of MX5's for road, racing and kit cars and these have been bullet proof.

The kit came with all the parts, bolt in, and it's been brilliant.  My tuned B now gives nearly 40 mpg on long runs in the new 5th vs 27mpg on the old 4th.  But the kit is now closer to £3,000.

This looks a nice conversion and even with the price there would probably be some takers for it in small chassis Triumph sixes except for a couple of problems:

First is space as the chassis was originally only designed to take a gearbox suitable for a much lower capacity and torque 4 cylinder engine.

Secondly due to that extra torque and relatively light weight we need a very tall ratio first gear which no other possible standard gearbox seems to have☹️