Fitting
a Mk3 Auto Box Into A Mk2
By
John Cooper
A
question on very few people’s lips I am sure!, but if
like me you are sitting with an immobile automatic Mk2 Zodiac it is a question
of profound importance. After managing to destroy my Mk2 auto box I thought I
would be able to pick up another easily. I was certainly wrong. Yes they were
out there but every one I was offered came with no guarantees. All the
potential seller’s would say was that it was working when they last used it.
Club member Dick Brown kindly lent me a spare box, but unfortunately the
reverse brake band was knackered in it (ironically the only gear I could get in
my previous box was reverse).
I
therefore decided to investigate getting my box overhauled. Nice theory, in practice
however I got quotes ranging from £1000 to £4000. Yikes (or if the truth be
told something a little less polite ran through my mind). To add insult to
injury potential rebuilders were only willing to offer limited guarantees as
they might have to use good second hand parts.
Ok
I thought what if I could get the parts and get someone I trust to build the box?
I therefore decided to source the parts. I quickly discovered that the box
weighed 13 and a half stone (thank you to club member Charlie Welsh who helped
me remove it one Saturday morning) and it was built under licence by Borg
Warner in this country. The box is known as a DG150M, the DG stands for Detroit
Gearbox and it was fitted to a number of American 50’s cars including Studebaker’s.
I checked suppliers in this country and the few that could supply parts wanted
a fortune, for example one supplier wanted £150 plus £100 surcharge for each
brake band. Thanks to some International Mk2 web enthusiasts I got put in touch
with a classic Studebaker parts supplier (Link to this supplier is in the
FAQ/Parts Suppliers) who would sell me brand new brake bands for $75 each.
Round
about the same time Mk3 enthusiast and expert Arthur Whitaker uncovered a horde
of brand new BW35 boxes (weighing in at a mere nine and a half stone) as fitted
to Mk3 Zephyrs and Zodiacs. They were still in their original Ford packing
crates complete with bungs in all the openings. They were selling for a mere
£85 each! I decided to get one for the Mk2 and if the worst came to the worst I
knew that it would always fit my Mk3. I met well known Glasgow Hot-rodder John
Thompson who advised me to let him fit the BW35 to the car. I wanted the car to
remain totally stock but as one of my workmates succinctly put it “I could
appreciate the car’s originality as I sat on the hard shoulder waiting for the
AA to recover it”. Ultimately the choice was made for me, brand new BW35 box or
DG150M box of unknown quantity. I decided to go the BW35 route.
Here
is how John figured out how to put a Mk3 box in a Mk2
car:
The
Mk2 flex plate was redrilled to take the bolts that hold the torque convertor
in place (the bolt arrangement is different on a Mk2).
Mk2
flex plate (picture left before redrilling)
The
input shaft of the Mk3 torque convertor was turned down by approximately an
eight of an inch to fit in the back of the engine.
A
section was taken out of the side of the bellhousing
to allow the starter motor to fit(a repair section was
later made up and welded in place to stop water and dirt ingress)
This
much and a little more had to be cut away with the grinder
A
couple of seven sixteenth bolt holes had to be tapped near the bottom of the
bell housing (one was for the starter motor if I remember correctly).
The
gearbox cross member needed a plate welded to the rear to accept the Mk3
gearbox mount.
Gearbox
mount (Top view)
Gearbox mount (bottom view)
A Mk3 Speedo drive (red)
was fitted to the Mk2 Speedo cable.
A Mk 3 props shaft
was used (manual and automatic cars use the same one) Mk2 yokes have different
spline arrangements from the Mk3 and are therefore unsuitable.
The
props shaft required a Mk2 tailpiece attached to the end
(I had the work carried out by IM Engineering of Glasgow who could not have
been more friendly and helpful. They told me that the Mk2 tailpiece was a very
common diameter and they could fit one from stock thus saving my Mk2 prop shaft.
IM Engineering are based in the East End of Glasgow and can be contacted on 0141
556 2424.
The
gearboxes linkages were fashioned by cannibalising the existing ones. John cut
and bent the linkages using oxy acetylene.
One
of the Mk2 linkages modified to fit Mk3 box
The
last hurdle to overcome was the fitting of the hydraulic cable. This was
achieved by mounting a bracket with a slot cut in to the bell housing made from
a piece of angle iron through which the cable was located. A length of rod and
a simple yoke held
with a split pin connected the cable to accelerator linkage.
Modified
kick down cable mount and yoke viewed from below.
My
thanks go to John Thompson, John Smullen and Charlie
Welsh, without their help I would not have got the job done. Thanks Guys !
Disclaimer:
The advice and guidelines given in these articles are given in good faith.
The owners and managers of the Galeforce Zephyr site will take no
responsibility for any injuries or loss sustained while carrying out the
described tasks and procedures or any consequences arising. Please read
the Safety First
Article
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