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MG MGA - T9 Speedo drive question

I have installed a Ford T9 5-speed transmission in my "A". Hi Gear engineering has provided a speedo cable that requires cutting a hole in the tunnel and routing the cable over the floor and out the toe board. I do not want to install it this way. Richfield makes a right angle transition drive that also corrects the speedometer. I looked them up and their is more than one available. I am now a bit confused of which one.

Does anyone know which one I should get? 43/10 rear gears....Ford T9 trans from a Merkur V6 (so its the HD one), and the speedo is 1450.

Can anyone tell me the proper drive to acquire. Thanks
C.R. Tyrell

Can't answer your question but you are going down the right route. Without the right angle drive I ended up with a lot of whiplash in the inner drive cable resulting in a jerky speedometer. At the time this was due to an undersize inner cable that was modified to have a Ford square drive on one end and a Jaegar square drive on the other. With the correct Richfield unit you can use the original MGA cable. Smooth as silk readings.

Steve
Steve Gyles

Richfield do have an instruction sheet what to do to get the right angle drive, easy job.
Siggi
Siggi

The standard BMC speedo drive is geared at 5 drive teeth to 12 driven teeth (1:0.4167). The T9 comes with 7 teeth on the driver and 23 teeth on the driven gear (1:0.304).
Standard you have:-
driveshaft RPM =1000
Speedo output RPM = 416
T9 has:-
Driveshaft RPM =1000
Speedo output RPM = 304. This needs to be raised to 416

You need a non reversing gearbox with a ratio of 1:1.368 (or as near as possible) to get the speedo output to drive the MGA speedo at the same rate as before.

Speedograph Richfield sell a 1:1.33 or a 1:1.4 gearbox (RGB1030 model) Pick which one you like best.

If you want to fine tune the setup, Ford sell three different speedo driven gears 22, 23 and 24 teeth. Sold in UK by www.burtonpower.com Replacing the gear is relatively easy, you prise off the dished cap below the speedo drive and pull out the plastic gear.

Hope this helps

Paddy

Paddy Reardon

Paddy, Your info really helps. I did order a speedo gear retainer from Burton Power as they are not available here. Good service from them. I will have a look at the drives from Richfield. Right now I can't proceed too much with that part of the restore until I get the drive.
thanks again.
C.R. Tyrell

Call Peter Gamble at Hi-Gear. He sells them for the transmission. I bought mine from him. You can get his number form the archives on BBS. It is a great working transmission and a very complete kit.

Jeff Becker
61 MGA Judson Supercharged
ZZZZZZZZZZOOOOOOOOOOOOOOOOOOOOOOOOOOOOOMMMMMMMMMMMMMM
JEFF BECKER

Jeff, I have ordered a right angle drive. I think Peter gets them from Speedograph-Richfield. I ordered direct from S-R , but I was surprised at how many drives there were. Paddy's information about the ratios helped a lot. I ordered the 1:1.4, because I would rather have the speedo reading slightly more than less..... less tickets that way.
C.R. Tyrell

This thread was discussed between 29/01/2014 and 01/02/2014

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