Overdrive virgin

[Jason C]

On 08/12/2021 at 05:51, Guppy916 said:

This is on my MK3 GT6 with a 2500 engine fitted, uprated J Type o/d, I used a Sparco Steering wheel with two buttons on, I use one for the horn and the other for o/d, If you fit o/d you should use the over drive inhibitor switches which disengage's o/d the moment you touch the clutch pedal, so you can never leave it on, I also made another brass contact ring to fit in the steering coloum as the photo shows, one contact for the horn the other for o/d, the steering wheel from Demon Tweeks, inhibitor switches from Rimmer's, This all  works great, o/d only on 3rd & 4th

Impressive engine @Guppy916 very nice work! 
 

Wow, this sounds like a fantastic setup. Can you please share more details about your inhibitor switch that disengages with the clutch? Assume you have a switch on the clutch pedal somehow? 

[Jason C]

On 09/12/2021 at 00:54, Slimboyfat said:

J Type 3 rail adapter plates are due in from the machine shop this week. It took a long while to get our casting company interested in doing a run this time (mainly due to relatively small moq) hence the lack of stock for the past year or so. Everything else for the conversions shouldn't be a problem.

It’s fantastic that the adapters are still being manufactured. I was seriously thinking of ordering one earlier in the year, but managed to source a second hand one locally. 

Edited December 9, 2021 by Jason C

[Jason C]

On 09/12/2021 at 01:03, Slimboyfat said:

At the height of it we were doing anything up to ten conversions a week, and we were doing them for over thirty years

That’s pretty incredible, you guys were like a Triumph production factory in your own right. 🔥

Where did you source that amount of gearbox’s - did owners always swap?

On 09/12/2021 at 01:12, Slimboyfat said:

Every conversion after that got a brand new prop

Great info! Didn’t think of this, my current propshaft has an Isuzu universal joint. Sounds like I may be better to purchase a new one. Are they “easy enough” to source? I’m in NZ so postage from the UK for a heavy weight is a little frightening. Curious, is the steel of the same quality for the new ones?

Is there an official measurement for a propshaft for an Overdrive? Or do you measure once it’s installed in the car…

[Jason C]

Could be dreaming, but did Triumph produce a guide for garages to fit Overdrives? Or were they generally installed at the factory on purchase?

If there are guides, blogs out there on a quality installation, wiring etc that would be very handy!  
 

These days are people fabricating there own gearbox tunnel covers?

Thanks all! 

[JohnD]

The O/d gearbox has a different output shaft to one without O/d.   It's not just a bolt-on job, but a full rebuild to add O/d.

So I doubt if they ever provided dealer handbooks.

 

[tr250]

On 03/12/2021 at 04:39, Jason C said:

Very interesting @tr250 so a J-Type overdrive is a little slower to engage? Is it noticeable? Does it feel kind of like an automatic delay (sorry newbie here)?
 

From what I gather the Vitesse 2 Litre would have originally had the D-Type, but I’ve sourced a J-Type as several people mentioned they are a stronger unit after refinements and easier to source.

I suppose an automatic delay maybe. It’s just more noticeable than the A-Type. The nice thing about the J-Types, Volvo used the J-Types up until 85. Actually beyond that, but I believe 85 was the last year for the Speedo gear. I guess in 86 they went to some sort of pickup. 

[Jason C]

18 hours ago, tr250 said:

I suppose an automatic delay maybe. It’s just more noticeable than the A-Type. The nice thing about the J-Types, Volvo used the J-Types up until 85. Actually beyond that, but I believe 85 was the last year for the Speedo gear. I guess in 86 they went to some sort of pickup. 

Sounds great @tr250 having not driven either variety I’m looking forward to it. Exactly, the J-Type sounds like a robust piece of engineering. 

[Jason C]

Found this Smiths Angle Drive, is this for my intended set-up? 

https://www.ebay.co.uk/itm/SMITHS-ANGLE-DRIVE-TRIUMPH-2000-2500Pi-TR3-TR4-TR5-TR6-VITESSE-GT6-/144302065378?mkcid=16&mkevt=1&_trksid=p2349624.m46890.l49286&mkrid=710-127635-2958-0

Better buying original, second hand in terms of quality or new? 
 

Lastly, do I buy a new cable to suit?

[glang]

Yes thats the item. The originals were pretty good and last a long time unless the cable seizes or someone has cross threaded it. That one looks as if a gorrilla has tightened up the brass coupler but it might still be alright. Dont know much about the new ones available except they can be expensive and probably come from India.

The existing cable would fit but probably wont be long enough as two different sizes were specified for OD and nonOD. Also NOTE the angle drive connection to the gearbox should be installed using a special washer to avoid thrust which could damage its gears.

I believe some people have got away without using an angle drive. They just connect the cable direct to the OD so that it passes through a hole in the gearbox cover and then runs beneath the carpet up under the dash.

[Jason C]

31 minutes ago, glang said:

The existing cable would fit but probably wont be long enough as two different sizes were specified for OD and nonOD. Also NOTE the angle drive connection to the gearbox should be installed using a special washer to avoid thrust which could damage its gears.

Perfect, thanks @glang Great tip with the special washer, didn’t realise I needed this. 

34 minutes ago, glang said:

That one looks as if a gorrilla has tightened up the brass coupler but it might still be alright

Ha, yes I noticed that! Maybe I will keep an eye out some more, although after other parts I have purchased, my gut feeling says it still might be better than a reproduction.

[Guppy916]

Hi I used Rimmer's Cable 60" https://rimmerbros.com/Item--i-GSD117 

This cable is 3" longer than STD

and Speedo Drive https://rimmerbros.com/Item--i-120694

Jason the inhibitor switches are operated via the gear lever remote as the photo shows

 

Edited December 14, 2021 by Guppy916
forgot gearbox photo, must be my age

[Jason C]

Hi @Guppy916 apologies for my slow reply, thank you kindly for the information.

The photograph with the complete gearbox and overdrive, with wiring is especially useful! Now I can see what the inhibitor switch and its bracket look like. I will need to source one of these. 🙂

I am still collecting parts, but when I get to it, is it easy enough to wire-up yourself? Perhaps someone has a wiring diagram floating round? 

The OD mount bracket plate, does this fit into the same location/bolt holes on the chassis? Also, is there an exact length the propshaft should be for the Overdrive? (this maybe a new thread).

Thank you

 

 

[Jason C]

Spotted this Overdrive floor cover plate, listed for a GT6 Mk2. Is this the same cover plate for the Vitesse, 2 Litre?

Could be fabricated, but this one looks ready to go (if it fits!).

 

[glang]

This site has the different propshaft lengths  Propshaft Problems : Canley Classics

And it sounds like you should download the free Triumph Vitesse/GT6 workshop manual with just about everything you need know. Look for Vitesse Steves site...

I think those covers are all the same and easy to make, even in aluminium?

[Jason C]

2 hours ago, glang said:

This site has the different propshaft lengths  Propshaft Problems : Canley Classics

Thank you @glang, a very handy reference. 
 

3 hours ago, glang said:

I think those covers are all the same and easy to make, even in aluminium?

Aluminium sounds like a good idea, I could potentially mould to shape on the floor, before cutting the steel. 
 

Thank you! 

[Guppy916]

Hi Jason just to add another job for you, I used Rimmer's P/No XKC1673FG, then I cut two access points for the speedo drive and gearbox fill port, these are very handy for checking the G/B oil and lubricating the speedo drive, they are held in with a couple of duzes fasteners, 

[nang]

Don't know if its been mentioned, I haven't read all posts. I ALWAYS use the clutch when engaging/disengaging overdrive. I do this as I once owned a Sunbeam Rapier which had a bad oil leak. .End story gearbox main shaft badly twisted on the splines which I reckon was caused by the previous owner not using the clutch( I know because he took me for a drive before I bought it ) and the shock loading was too much.

[Rutty]

3 hours ago, nang said:

Don't know if its been mentioned, I haven't read all posts. I ALWAYS use the clutch when engaging/disengaging overdrive. I do this as I once owned a Sunbeam Rapier which had a bad oil leak. .End story gearbox main shaft badly twisted on the splines which I reckon was caused by the previous owner not using the clutch( I know because he took me for a drive before I bought it ) and the shock loading was too much.

Have you ever driven an automatic? Well you don't lift off or use a clutch on one. Infact on kick down you have your foot flat to the floor, but the gear change mechanism is the same principle as OD. So you can probably guess No I don't use the clutch or lift off, as others have said the great thing about OD is you can use it while overtaking for a quick gear change, then on twisting roads 3rd gear and OD is a dream. The only reason I can see for using the clutch is if your OD or gearbox is knackered possibly due to an oil leak!

[yorkshire_spam]

I'm with @Rutty on this one, I never use the clutch when switching the OD in/out, that's one of the joys of OD... I just wish I had OD in 2nd for climbing mountain passes... a 2.5 gear would really be handy between the hairpins. (I've contemplated sourcing a P-Type and modifying the interlock to allow OD 2nd... but too many projects!)

 

[RobPearce]

Just now, yorkshire_spam said:

I just wish I had OD in 2nd for climbing mountain passes...

We did that on my brother's old Mk2 Spitfire. It made Welsh hills much nicer. Mind you, that car had a refurbished gearbox and overdrive and a completely knackered engine, so high rev thrashing was not good.

I'm also with @rutty on the clutch thing. It's daft - the overdrive IS a clutch, you don't need a second.

[Hogie]

1 hour ago, Rutty said:

No I don't use the clutch or lift off, as others have said the great thing about OD is you can use it while overtaking for a quick gear change, 

+1

Depressing the clutch when changing into or out of OD is really not required.

If you simply match the engine revs with what you are doing will give a beautiful engagement.

However if you get it wrong when changing down it can make an awful clunk.

 

Roger

[Pete Arnold]

This topic seems to crop up on this forum at least once a year.

So here's a copy of the relevant page from my official Triumph Vitesse 2 litre Owners's Handbook; not sure which year but this book is part no: 545006.

Perhaps we can now put the clutch to rest!!!!!!!!!!

[nang]

Fair enough. I still don't see anywhere that says don't use the clutch .I only remember the bent splines in my Rapier. so I'll keep doing  it my way. Thanks. Tony.

[RobPearce]

8 hours ago, nang said:

I still don't see anywhere that says don't use the clutch

Two things:

 - it doesn't suggest you should, which is a good clue

- it does say "A uni-directional roller clutch enables the change into, or out of, overdrive to be made when transmitting full power without loss of road speed." That's a pretty damned clear "don't use the clutch" to me.

[glang]

It does seem like a big loss of the functionality of OD to have to drop power and press clutch during its operation. Also, a minor point, but isnt the OD hydraulic oil pump driven by the gearbox output shaft so pressing clutch, certainly when engaging OD, can momentarily deprive it of power?