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MG MGB Technical - Help on a Daimler Auto box

I know this is the MG BBS, but I have found that if someone on this site doesn't know the answer nobody does, and the Daimler BBS crowd seem to think that the Jag version is not really worth worrying about.

I am helping a mate with a 2.5L V8 Daimler/Jag MKll who has a burnt out front clutch in his Borg Warner 35 auto. He has got his hands on another box that was fitted to a 2.6L 4 cyl Sigma and we are hoping to simply transfer the internals from that box to the Daimler box.

My question relates to the springs in the valve assy that control the shift points. Should we use the springs from the original Daimler box or can the springs from the Sigma box be used.

I guess what I am asking is, do different cars have different control springs fitted or are all BW 35 boxes the same.

Thanks
Tony
Tony Oliver

Looking at it from a stricly scientific point of view; Are the various springs the same? or put it another way if with two springs, from the same location in the box are of equal coils thickness etc, then they are the same? Would that not be correct? But if from one part of the box even though they may both be Borg Warner 35 has two different 'value' spring perhaps one has been set up for the 'specific' engine? Mike
J.M. Doust

AFAIK, such things are set to suit the engine, car, and perceived requirements of buyers (mostly smooth and imperceptible shifts). Which is why you can "upgrade" autoboxes for better shifting etc. So, you need a guy who has experience with these anchors, widely used in many cars worldwide. Quite likely you don't want either of the OE arrangements.

FRM
FR Millmore

Thanks gents. I have found that the 2.5L V8 has figures of

140 BHP @5800 RPM and 160 Lb Ft @ 3600

2.6L 4 Pot has

131 BHP @ 4750 and 162 Lb Ft 2 4000

so the engines are fairly close to each other. On that basis I would assume that either spring set would work as to the best of my (very limited) knowledge the change points are related to power and torque.

My reason for asking is that the clutch was OK one week and totally shot 3 weeks later, and not knowing a lot about autos (but rapidly learning) we were a bit concerned that the pumps or valves may have caused the fault so we wanted to use all the bits out of the donor box.

Cheers
Tony
Tony Oliver

I am no into autos, but there is no clutch as such, it is callelled a 'torque converter', an is fluid driven, you can have high stall converters and low stall( means,up to what revolutions, can you hold the engine on a brake before the engine dies.)on the floor of the auto transmission box will be a plate, for what of better words, which will direct fluid through different diameter holes, and detent balls, these can control, points of shift and whether they are soft or hard. If you say the 'clutch died'? might be the transmission to the torque converter?. A good auto workshop manual might clarify. mike
J.M. Doust

Hi Mike,
I suspect that what Tony calls "clutch" is what we call bands.
I.e. the internal clutches / bands that engage different gears.

Herb
Herb Adler

Herb. Yes and no. WSM calls them clutch plates, it is a multi-plate wet clutch such as used in motorbikes. There are two, one for all forward speeds and one for reverse only. Bands are also part of the box, they lock up the planetary gear carriers to get the 3 speeds. In the BW35 they are part of the gear box itself.

Mike, you are also a bit right as some converters actually have the clutch plates internally, or so I have read.

Listen to me, I'm a bl**dy expert on autos now!!!!! First time I have ever worked on one in 45 years of working on cars. Give me a manual any day :-)

Cheers
Tony
Tony Oliver

Tony there are many variations in the type 35 box. Some had more plates in the clutches and there were many mods over the years as well. Even the front wheel drive version in the Austin 1800. They are not hard to repair if you know what your doing but if not you can get a change over pretty reasonably priced or yours rebuilt for the same and that would be the way to go. Denis
Denis4

This thread was discussed between 07/05/2012 and 08/05/2012

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