Bw65 vs Bw66 questions....

Oldskoolrob

Active Member
Howdy,
I'm installing a 3.5 into my Mk2 Cortina as some of you know. I've ended up with both a BW65 and a BW66. The BW65 is 'reputed' to have been rebuilt 20K Kms ago and comes with a reconditioned (never installed) converter. Apparently it's been converted from a Jag to suit a Rover and has had additional work to make it a tighter box (more or better plates or something - the seller wasn't a guru). The outside looks like crap but inside the bellhousing looks nice and clean, seals look good. It is, however very hard to change gear and I can't turn the output shaft.

The '66 is from an SD1 and is very clean on the outside, easy to change gears and rotate output shaft. However it's filler tube got busted in transport, and it has it's original converter. I can see the input seal will need replacing - there's no oil but part of the orange rubber seems to be missing.

Due to doubling up on costs I don't really want to take both boxes in to be assessed by my local auto guru but I was going to take whichever box I choose in for a service/check-over.

My question is, are there any strong opinions on which box would be a better choice to use? Any advice on the sticky shifts/output of the 65? Should that be a concern, or is it evidence of the alleged upgrades....?

Cheers,
Rob.
 
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As far as I remember the differences between the 65 and 66 are that the 66 has a deeper sump (or should have) so different dipstick and tube, (and possibly a spacer to lower the filter but don't quote me on that), larger input shaft, and converter to match, and an adjustable kickdown bracket.

I think that's it, but if I remember anything else I'll add it later in an edit.

66 is improved for a reason, but if you don't intend giving the 65 a hard time it should be fine.
 
Thanks Harvey, as always I appreciate your knowledge. One question I do have is about the output yoke. The Cortina has a live axle and as such the yoke slides in and out of the rear of the box with suspension movement. The SD1 had a live axle didn't it (?), so a sliding yoke shouldn't be a problem for the box...? Or did it have a 2 piece tail shaft to compensate for the change in length?
 
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Hi, How long have the 'boxes been sitting out of the cars unused? They don't like sitting around because the seals dry out when not covered in oil and can give problems when pressed back into service. I would view any 'box with suspicion, so I would pick the cheapest and get it rebuilt.

Colin
 
Hi, How long have the 'boxes been sitting out of the cars unused? They don't like sitting around because the seals dry out when not covered in oil and can give problems when pressed back into service. I would view any 'box with suspicion, so I would pick the cheapest and get it rebuilt.

Colin
Good point, I guess. I will be getting the one I pick checked out thoroughly by an expert. They're all the same price as I got them in a job-lot :)
 
The SD1 had a live axle, with a torque tube extension on the front end, so there would be miniscule fore-aft movement needed in the prop shaft. The prop shaft had a CV joint on each end, which could handle angle changes as the axle moved up/down, and some degree of plunge - these were sealed to the tube with rubber boots. The odd part is that the end flanges are different - one is a std rectangular bolt pattern (obviously - it fits to an LT77 output flange), but apparently the rear end has a square pattern.
 
Ok cool - looks like a custom driveshaft will be in order. Not a huge deal compared to the other surgery that's being undertaken...
 
Out here Fords, Chryslers and the P76 all used BW boxes. P76 was a beefed up 35 but I think the big Chryslers and centuras used the 65 and they had (from memory) the sliding yoke tailcone and output shaft. Alternatively you can just get the Rover end put onto your ford tailshaft and balanced for not much.
 
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