Shorten a bellhousing or get a tiny propshaft

[ratwing]

Briefly, I want to replace an LT77 with a ZF4HP22 uprated with HP24 internals but it doesn't leave enough room for a propshaft, not even my short one. My options are an even shorter prop or a combination of flex plate/spacers/torque converter that's short enough that I can get the bellhousing cut'n'shut.
Does anyone know of a company or person that would shorten an aluminium bellhousing, or who might be able to make a really tiny propshaft?
Here's the problem, this is the prop I'm currently using with the LT77, a local company said it's the shortest they could make but it's too long for the modified ZF auto, it needs to be 23mm shorter and able to take the 290lbft of torques from the 4.6 RV8. (ignore the longer prop, the old 4 speed Rover p6 box used that one)

[harvey]

On the ZF conversion in the Triumph Stag they use a BW35 bellhousing, mate the ZF box to that, bolt the ZF converter to the Stag flexplate, and that gets rid of the ZF extra spacer and flexplate used on the RV8, so would shorten the length by the thickness of the spacer and flexplate which is probably 50mm or so, so it can be done.

[DaveEFI]

What mods are needed to mate the B-W bell housing to the ZF box?

[stevieturbo]

I'd prefer a CV type joint, ideally a tripod style that has some ability to move fore/aft

But that's pretty damn short !

[Ian Anderson]

How about something like this?

https://www.ebay.co.uk/itm/112441959125 ... gJr4vD_BwE

https://www.demon-tweeks.com/metalastik ... lsrc=aw.ds



Original GT40 used similar so they can be made to take torque.

Ian

[stevieturbo]

How about something like this?

https://www.ebay.co.uk/itm/112441959125 ... gJr4vD_BwE

https://www.demon-tweeks.com/metalastik ... lsrc=aw.ds



Original GT40 used similar so they can be made to take torque.

Ian

Most OEM cars use them so definitely very common, torque handling ability is not an issue.

[paul c]

which torque convertor are you using, the large P38 convertor doesnt use the thick spacer like the small and medium convertor, so you wouldnt be able to shorten it that much, Ashcrofts also state that the upgraded 22 is 15mm longer than the standard 22 due to the thicker 24 front pump.

Discovery also used the rubber donut on the diff flange

[DaveEFI]

Would you need the largest TC LR used on a light vehicle like a trike?

[ratwing]

On the ZF conversion in the Triumph Stag they use a BW35 bellhousing, mate the ZF box to that, bolt the ZF converter to the Stag flexplate, and that gets rid of the ZF extra spacer and flexplate used on the RV8, so would shorten the length by the thickness of the spacer and flexplate which is probably 50mm or so, so it can be done.

Is a BW35 bellhousing big enough to fit round the largest of the 3 torque converter sizes?

[ratwing]

I'd prefer a CV type joint, ideally a tripod style that has some ability to move fore/aft

A couple of CV joints sounds ideal, the diff is solidly bolted to the chassis so only need to allow for enough plunge as the engine/gearbox moves on the rubber mounts but which ones?

[ratwing]

What mods are needed to mate the B-W bell housing to the ZF box?

Apparently the transmission end is machined off and a plate with the ZF pattern is welded on.

[ratwing]

How about something like this?

https://www.ebay.co.uk/itm/112441959125 ... gJr4vD_BwE

https://www.demon-tweeks.com/metalastik ... lsrc=aw.ds

Original GT40 used similar so they can be made to take torque.

Ian

A nice idea but I'm pretty sure the Rotoflex PCD bolt pattern is too big to drill on my gearbox and diff flanges so will need adapter rings. I think this gearbox flange/adapter ring/rotoflex/splined joint/rotoflex/adapter ring/diff flange combo will be quite long.
Unless there's some way to have the input and output flanges on the same side so the splined section is inside the rotoflex?

[ratwing]

which torque convertor are you using, the large P38 convertor doesnt use the thick spacer like the small and medium convertor, so you wouldnt be able to shorten it that much, Ashcrofts also state that the upgraded 22 is 15mm longer than the standard 22 due to the thicker 24 front pump.

Discovery also used the rubber donut on the diff flange

Yes, I was planning on using the big one (stamped 100 120) because of the engine's torque figure and thought it had a thick spacer but you're right, I looked at the parts I've had stored for a few years and the only spacer is a thin one between the ring gear plate and torque converter plate. It's looking like there isn't a way to shorten the front end if using all standard ZF parts.

[DaveEFI]

What mods are needed to mate the B-W bell housing to the ZF box?

Apparently the transmission end is machined off and a plate with the ZF pattern is welded on.

That would be because there is no ZF bell housing to fit the Stag engine. There is for the RV8.

[ratwing]

Would you need the largest TC LR used on a light vehicle like a trike?

To be honest, I don't know.
The trike's all car parts and steel panels and I've no idea what it weighs when two-up with a fortnights worth of camping gear and 16 gallons of petrol but it's no lightweight and not at all aerodynamic or streamlined either.
Then consider the long distances at high speed we do on the unrestricted sections of the German autobahns (which is probably what's killing the LT77) and I thought the big one would be the one to use?
To give some idea, this was taken in 2017 coming back on the ferry and since then we've got a bigger tent, bigger chairs, a bigger table and a bigger cooker too. (sometimes we're put inside with the cars, sometimes like here we're out on deck with the artics)