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MG MGB GT V8 Factory Originals Technical - V8 Speedo, Revcounter

I have a Rover V8 conversion with SD1 g/box. Can anybody provide some guidance on how to connect these up to the standard 1987 MGB GT (1800) instruments or any alternate methods or parts needed.
Many many thanks as always.
Brian
Brian

Brian

I got a conversion speedo cable from Midland Sports and classics ltd, this allows you to use the standard speedo with the Sd1 gearbox, make sure you let them know what size is required into the rear of the gauge, they sent me the wrong one first. don't have a part number the bill just says conversion, but they are pretty helpfull on the phone (01905 621331)cost me £23.

You will have to get the speedo recalibrated though, there are several companies that do it, they require you to give them some figures (size of tyres, distance covered with 3 turns of the wheel etc...) you can post it to them and they will recalibrate it)

You can re-use the tacho. this requires a modification to the internals (a connecting soldered wire)to change it from 4 to 8 cylinders, there is a bit of information on the archives.

hopefully someone else on this site will give you a bit more information, i still need to do my tacho.

Graham
GLG Lavis

I wired the pot so it was outside of the tach and I could calibrate it in the car with the engine running and another tach as the reference.

http://www.zaks.com/mgb/leonsmgb/Better_tach.htm


Here is how I adapted the speedometer
http://www.geocities.com/v8mgb/speedometer.html
Jim Miller

Brian,

if there is a chance to buy one of the early SD1 tachs, you can change all the internals and refit it. It is easy to do and works perfect. I did this 20 years ago and it is still O.K..

Another chance is to look for a Volvo-Penta (marine) tach. Many of the V8 marine engines have been swaped to diesels meanwhile and the tachs are offered very cheap. They are also 80 mm diam but all stainless steel and calibrated to 6000 rpm on the scale.

The conversion with a spindle drive poti will work although the instrument does not respond as good as a V8 tach.

Ralph




Ralph

Dave Vale at V8 conversions Farnborough Kent has the parts you need.

Some if not all SD1's had electrical drive to the speedometer and you will need the mechanical drive take off, and the cable, Dave has just had some mechanical drive units made, and I believe they are not available elsewhere.

V8 Conversions.
Tel. 01689 858716
Kevin Jackson

You'll need a 100Kilo ohm adjustable resister. These measure about 5 by 5 by 20 mm and have a screw adjustment. They only cost around $2.
For the Tach adjustment, solder on one of the wires to pin 4 of the 100kohm variable resistor and just hold the other in place on pin 7.
Start the car, set the throttle,to 2000 RPM for example, hold the wire in place and adjust the resistance so the revs' read half. Take the wire off and on while fine tuning your resistor. Do this at a couple of other RPM's. Solder the free wire in place.
Put the tach back together and done.
Peter

This thread was discussed between 12/05/2007 and 15/05/2007

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