4 speed auto & crossflow?

[wagon]

Hello all!

My BW40 is dying. It copped a gutfull of water courtesy of a leaking radiator cooler.

Two options:
1) Rebuild BW40. I'll still have three forward gears, same as always.
2) Install a EA-AU 4 speed auto. We did some measurements today, the boxes

1) Flexplate holes for the convertor in the same spot
2) Spigot bush on convertor the same size
3) Tailshaft spline is the same
4) Rear mount should bolt straight up, if not very simple to modify.
5) Shifter mechanism should be trivial
6) Oil cooler lines easy
7) Electrics won't take much (already have efi)
8) The only maybe.... the bell housing. I'm going to attempt a 'cut & shut' of two bellhousings to make one. At this stage a cut just behind the starter bulge on both bellhousings should suffice.

Have I missed anything? Why hasn't it been done before?

Thanks.

Wagon.

 

[aussie7mains]

Why?
That wont be an easy one, early EA BTR 4 speeds have a dedicated control box which talks to the ECU which I doubt will be compatanle with your early EFI.
Later types are controled by the power train ECU, which wont work with the crossflow efi.
The best option to adapt the bellhousing would be to make a plate to bolt to the engine block which accepts the later bellhousing pattern, not easy without the drawings fro both blocks, a lot of measuring up to do, Castlemaine rodshop might help.
Might be easier to get a OHC 4 litre and transplant the whole lot.
Otherwise you could stick a C$ behind your crossflow or just simply rebuild your BW40.
A7M

 

[wagon]

Thanks for your thoughts A7M. The electronics are no problem at all. I have late model (Megasquirt) EFI and I'll make it talk to the transmission controller one way or another. An adaptor plate cannot work since the starter is on the opposite side on the OHC motors and would foul the bellhousing ; hence the cut and shut bellhousing idea.

I want the 4 speeder because of the extra economy and a C4 is heavier and they're getting scarce - plus no overdrive. The X-flow I have is strong and not very old - plus it looks right in a 1980's Falcon engine bay - less trouble should plod have an 'inspection'.

 

[aussie7mains]

I can safly tell you a BTR is NOT lighter than a C4.
Good luck with the electronics.
If your looking for economy get a manual tranny, no auto can match them, the internal losses in a auto FAR outway any supposed gain from an overdrive.
Even overdrives in manuals are a bit of a waste to my mind, how can an indirect drive match the losses of a propely geared maual in direct drive.
A7M

 

[wagon]

I can safly tell you a BTR is NOT lighter than a C4.

You're probably right - the C4 guts are tiny. The bell-housing on a C4 is cast iron, though. The shift linkage is on the wrong side too and the kickdown mechanism could be a headache with efi.

Good luck with the electronics.
If your looking for economy get a manual tranny, no auto can match them, the internal losses in a auto FAR outway any supposed gain from an overdrive.
Even overdrives in manuals are a bit of a waste to my mind, how can an indirect drive match the losses of a propely geared maual in direct drive.
A7M

I like automatic transmissions. I know it'll get better economy, since at the moment it's doing nearly 3grand at 100km/hr. I'd expect under 2grand with my 2.92diff. That alone should being an economy improvement just from the fact the motor won't be revving so hard.

We'll soon find out! The BW40 lost reverse yesterday, so I got stuck. The machinist/welding man has the bellhousings to cut&shut, so it's all starting.

 

[wagon]

The bellhousing is being welded up & machined. Tonight we ran up the transmission and controller on the bench (using signal generators and such). All good so far. We even extracted fault codes! Hopefully this weekend the whole lot will be done & mobile.

I'll post pictures soon.

 

[addo]

Icksillent. Are you going to get it going first as a manually shifted box, then increase the electronic aspects?

 

[wagon]

I'm going with a full automatic setup, just like what you'd have if you bought an EA-AU.

I wonder what the interest would be for 'conversion kits' to do this? Once it's all sorted out and has been running around for a while I might consider selling something along those lines.

 

[wagon]

Well... I drove the Falcon home last night. It easily pulls 4th gear at 50-55km/hr on flat ground. It did get 4th at 40km/hr up a steep hill too because I haven't yet hooked up the TPS. The controller must have thought I was just putting along.

The job was pretty easy, really. I think it's well worth it!

Question : can you use a BW40 with a 'pre-crossflow'? If yes, then I'd expect this 4-speed auto conversion would work on those, too, provided the transmission tunnel on the car is big enough.

I'm going to get some more photos and post them up soon.

 

[wagon]

Well... I've now put about 1500km on the setup now and it's great! The economy is improved a lot - it's now around 11litres/100km on the highway. At 100km/hr it's doing all of 1500rpm, nice and quiet.

The factory electronic controller works fine in conjunction with the megaquirt box and the shifts are really smooth - which you'd expect.

I'd like expressions of interest for kits for this conversion. I reckon it could be done for around $1600 including a good second-hand transmission.

 

[xdee]

Well done Wagon. You should seriously think about going to a 3.23 or 3.45 diff now that the auto is proven. You won't lose much, if any, economy. But you will pick up a heap of performance.

 

[wagon]

I've considered shorter final gearing, but the 2.92 lsd isn't broken so I figure the grief changing ratios (both mechanical and from the missus) makes it not worthwhile at this stage. It would also mean the whole show would be spinning at around 1900rpm at 100km/hr - a fair increase over 1500rpm.

But, if the diff were to die....

 

[wagon]

Here are some pictures.. next time I have it on the hoist I'll try and remember to take more. It's been months now, no troubles at all. The economy is improved by at least 50km out of a tank around town and maybe 100km on the highway.

BTR85LE on left, BW40 on right. Same length!

Original BW40 flexplate was used... same spigot, same converter bolt location/size.

Cooler lines needed some mods.

This crossmember mount...

and this crossmember mount got the grinder treatment to enable clearance for the much wider 4 speeder.

Original shifter had to go.

 

[Emcopac]

Hello all!

My BW40 is dying. It copped a gutfull of water courtesy of a leaking radiator cooler.

Two options:
1) Rebuild BW40. I'll still have three forward gears, same as always.
2) Install a EA-AU 4 speed auto. We did some measurements today, the boxes

1) Flexplate holes for the convertor in the same spot
2) Spigot bush on convertor the same size
3) Tailshaft spline is the same
4) Rear mount should bolt straight up, if not very simple to modify.
5) Shifter mechanism should be trivial
6) Oil cooler lines easy
7) Electrics won't take much (already have efi)
The only maybe.... the bell housing. I'm going to attempt a 'cut & shut' of two bellhousings to make one. At this stage a cut just behind the starter bulge on both bellhousings should suffice.

Have I missed anything? Why hasn't it been done before?

Thanks.

Wagon.

Hi how did your Bellhousing come up successfull ? I’m looking at using a Btr on a pre cross 250 ! Thanks