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Chicagoland MG Club: Driveline
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  Chicagoland MG Club:Driveline
Putting a Five Speed in a MGA
Would you be interested in putting
a 5 speed in your MG?

Paul Urquhart Why put a 5 speed in a 40-year-old car (MGA)? There are a number of reasons to do it and a number of reasons not to. For me it was to make the car a better road car and to lower engine RPM at highway speeds. There are kits sold to do this change so I am not the first to do it.

Over the past two years I have been working on putting a 5 Speed transmission in my MGA and have done a lot of work to do that. The project is almost done as of this date and I am in the testing phase now.

Original MGA gearbox
Standard MGA gearbox

The transmission that I chose is out of a Nissan 240 SX "89" it is just about the size of the MGA tranny it has a built in bell housing and runs a 12" flywheel the input shaft is the correct length and size. Other good points are that the starter and clutch lever are almost in the right place on the right side. I also used the Nissan flywheel and clutch but had to do some machine work on the flywheel to get it to fit the MG crankshaft. The making of the engine back plate was one of the biggest challenges and has the most time invested into it. Finding a starter to fit is the next challenge that took a lot of research but one was found and it works well. The rest of the work is in getting it in the car making some room and getting it all lined up to fit in the drive shaft.

Nissan 5-speed gearbox
Nissan 5-speed gearbox and MGA engine, mounted in MGA frame

Only a few modifications have had to be done on the frame for the trans mount and the trans tunnel had to opened up on the right side to make room for the trans. In all the fit into the car was not that bad. I will be installing a new electronic speedometer to work with the new transmission and the change over will be complete and the highway driving will start.

I would like to know if any of you would be interested in putting a 5 speed in your car? How much would you be willing to pay for the main parts as a kit? As for me I will start working on fitting one of these 5 speeds in a 77 "B". The making of the engine plate is the most critical part of the stuff needed to make this work.

Steve Merical and I will be putting this set up into his "A" soon.

Let me know if you have some interest or questions I will be more than happy to try to answer them all.

Paul Urquhart -

Modified opening top and side of tunnel
Open top & side of tunnel
Fiberglas top cover
Fiberglas top cover
Steel side cover with slight bulge
Steel side cover with slight bulge
Finished interior in MGA
Finished interior in MGA
Flywheel & pressure plate - Nissan & MGA
Flywheel & pressure plate
Nissan left - MGA right
Machined engine rear plate
Machined engine rear plate adapts
Nissan bellhousing to MGA engine

          MGA       MGA      MGB 3sync  MGB 3sync  MGB 4sync  Nissan
          Standard  Close    Standard   Close      Standard    240
          Trans     Ratio    Trans      Ratio      Trans      Trans
1st gear  3.64      2.54     3.64       2.44       3.44/3.33* 3.321
2nd gear  2.21      1.62     2.21       1.62       2.167      1.902
3rd gear  1.37      1.27     1.37       1.27       1.382      1.308
4th gear  1.000     1.000    1.000      1.000      1.000      1.000
5th gear   --        --       .802       --         .82        .759
                           Type D OD             Type LH OD
                                         * = post 1978 1st gear

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