converting a bw35 to modern 4 speed autobox, anyone?

[TR7Driver]

I can remember reading a thread about someone doing a conversion on a 2500 and talking about supplying a kit but I can't find the thread and I think it was quite old and it might not have been on this forum. Has anyone any knowledge? It would be so nice to be cruising at around 3500rpm at 70mph, as at the moment its around 4200rpm and as its not locked its so inefficient.

I think Monarch do one (expensive) for the stag but I assume the engine / gearbox join-up bolt locations would be different between the 3000cc V8 and the 2500cc engines.

Cheers

[andyborris]

I may be wrong ( usually am!) but aren't the Stag and 2000/2500 gearboxes the same?

Andy

[harvey]

ISTR the ZF box was used and mated to the BW35 bellhousing. Someone I know has just added an overdrive to the BW35, and the same could be done with a 65 as well.

[Thorsten]

Someone I know has just added an overdrive to the BW35, and the same could be done with a 65 as well.

I'd be very interested to get more information on this conversion!

Years ago it was mentioned on a Stag forum that Del Lines might have offered this converion in the 1970s but no further information was available.

As it happens I find automatics very attractive (and accidentally the three Triumphs of mine are all autos) only motorway runs are a bit stressful, so if your friend would share his invention, I would be very grateful!

Best regards
Thorsten

[harvey]

I'd be very interested to get more information on this conversion!

An overdrive has been sourced and modified into a self contained unit, which has been mounted directly to the back of the 35 box flange to flange, and the unit itself in the current application is mounted on the same crossmember as the rear of the gearbox. Currently under evaluation and performing well, apart from a slight prop vibration after the prop was re-cut & balanced by so-called propshaft specialists. Personally I think that part would have been left as it was done during the conversion rather than relying on "experts", but that's how you learn things along the way. It's still running the original speedo cable on the gearbox, so that will be extended to reach the overdrive, and the speedo head recalibrated to match. All the wiring and switch has been done along with an isolator to prevent engagement of the overdrive in reverse. Currently the car is in daily use for long term testing, and a later better spec overdrive has been obtained to do a Mk2 version. It's early days as the whole project was only decided on about a month ago and that's how long it's taken as a part time job to get it to this stage.

[TR7Driver]

I may be wrong ( usually am!) but aren't the Stag and 2000/2500 gearboxes the same?

Andy

Hi Andy, yes, you're right and it's also used by the TR6 and Dolomite Sprint but I'm not sure if the bellhousing is the same for all. I do know that an alloy spacer is used between the Sprint bellhousing and the engine plate that bolts to the back of the engine. What I don't know is if an engine plate is used on the Stag V8 and 6cyl engines. If it is and the bolt patterns are different between the two then it would be relatively simple to make up a plate to match the 4speed autobox adaptor and the 6 cyl block.

Jim

[TR7Driver]

ISTR the ZF box was used and mated to the BW35 bellhousing. Someone I know has just added an overdrive to the BW35, and the same could be done with a 65 as well.

I'd heard a rumour that this had been done so now you're confirming it. Thing is I think I'd prefer the 4 speed autobox route as they are more efficient with regard to less transmission power losses.

Cheers,

Jim

[harvey]

The ZF box (ZF4HP22) from the LDV Convoy V8 gives you a 4 speed auto with an overdrive top and a lock up converter, as well as a cable speedo. Loads of other variants, but some are electronic, and none have a cable speedo. Getting rarer but still available, I've sourced a few at between £350-400 complete, and one I sold a while back has just been sold on ebay for £405. I'm just about half way though fitting one into a rod, but I can't say I can remember what's involved in mating it to a BW35 bellhousing, but it can't be that difficult.

[Thorsten]

Cheers, Harvey,

I hope you'll keep us updated on the evaluation process...

Best regards
Thorsten

[englishbull]

ISTR the ZF box was used and mated to the BW35 bellhousing. Someone I know has just added an overdrive to the BW35, and the same could be done with a 65 as well.

How much did this conversion cost?................I enquired and it was about £800.
Sorry just seen price...........