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MG MGA - Five Speed Drive Shaft Questions

I am in the middle of my five speed conversion project. It is taking a bit longer as I decided to take a different route and not purchase a kit. I am using a five speed (Type 9) from a Ford Merkur which has the 3.3 ratio first gear and the beefed up layshaft front bearing. I adapted a bell housing from an early low starter 1500 transmission and am now occupied with the task of engineering my own drive shaft and mounts. I have two questions that hopefully the five speed users can answer:
1. Is anyone able to tell me the length of the drive shaft used in the MGA conversion supplied by the usual vendors. Length of tube, overall length, or distance between the "eyes" of the u-joints on welded on the tube? Any or all of these dimensions would be helpful.
2. What size u-joint is used in the resently supplied drive shafts? Is this the same size as the MGA uses or is it larger?

Thank you anyone in advance, for whatever help or information you can give.

BTW for the curious--the reason I took my chosen route is mainly cost. I acquired the transmission for $125, the bell housing with machine shop work is less than $300, The drive shaft will be about $200, and the mount maybe $50. Add to that complete rebuild materials for the gear box, bearings, syncros, gaskets and first and reverse gears for $300. Top that off with the Quaife quick shift gear lever for $75. I believe that adds up to $1050 US without my labor (which according to my bride is worth nothing)--a very reasonable acquisition cost.
James Johanski

The tube length is 76cm
eye center to eye center = 82-1/2cm
Hi Gear has it marked as 825mm length
tube is approximately 5 cm dia
Cant find makings on the U joints
Chris Velardi

This the driveshaft in the HiGear Kit


Jim Ferguson

This is the flange end with U joints. They look the same as stock MGA on top. Note the 5 speed is a larger diameter shaft.


Jim Ferguson

If you want a stronger rear U joint you can use a Datsun 280Z rear yoke/flange assy. The Datsun driveshaft bolts to the MGA differential. I broke the stock MGA rear U joint in my RX7 powered 58 MGA on the first shift. 20 years later the Datsun part still works fine.
R J Brown

RJ how does that RX7 engine fit and run in the MGA?
Chris Velardi

James,

Sounds like a plan, I have a spare MGA box and type 9 boxes are still quite easy to get here. I am very interested to see how you get on, please post some pictures! How does the gear lever position work out?

Neil
Neil McGurk

As a side note to the 5 speed conversation what is the purpose of the threaded holes on the face of the replacement spigot bush ? I'm trying to make sure mine does not end up contacting the washers on my 3 bearing lightened alloy flywheel I had mated to my 5 bearing engine. see last 3 photos here
http://picasaweb.google.com/chrisvelardi/MGARebuild#
Chris Velardi

Chris, those washers look to be oversize and too big for the bolt thread. Perhaps you should change to a standard size. Also no lock washers?

Neil
Neil McGurk

Just been having (another) look at your pictures. I see the flywheel came like that from Fab Tek, maybe worth giving them a call.
Neil McGurk

Chris
The RX7 engine and trans fit easily. A self made bracket bolts to the front of the engine and sits on stock MGA mounts. The drivers side floorboard was narrowed slightly and the tunnel reshaped to clear the starter. Custom header brings exhaust under engine to the stock position.
Triple the power turns the car into quite a little beast. Easiest swap out there. Reversible too.
Picture shows mockup of front mount and MGB suspension.


R J Brown

Chris,
I believe the threaded holes on the face of the spigot bushing are for removing the bushing. Though when I put the bushing in it took several(read many) whacks with a large hammer. I have my doubts the threads would hold up to a puller if one were to remove the bushing using that method.
Before anyone installs the bushing, I would suggest to look for any burrs in the crankshaft hole and to make sure it is starting in straight.

Ray
Ray Ammeter

This thread was discussed between 24/09/2009 and 28/09/2009

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This thread is from the archive. The Live MG MGA BBS is active now.