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MG MGB GT V8 Factory Originals Technical - Automatic Flywheel to Manual Transmission

I am having a 4.0 engine installed into my MG. The engine came from a 2000 Discovery. My rover mechanics mentioned that the flywheel that this car has may not work since it was designed for an automatic transmission and has grooves cut out for the start positioning. In addition this flywheel is very heavy. What can I do to reduce the weight and also mate it to a T5 transmission? Do I need to get a new flywheel? And if so from what car? Do they make any manual transmission flywheels for that year car? Any help would be greatly appreciated.
Samy Cuzmar

Hi Sammy,
Any of the major V8 suppliers can get you the correct flywheel. I bought mine from Ted Schumacher and it was drilled for the Rover Sd1, Camaro, and I think a Ford clutch too, but I'm not sure. The flywheel he carries also weighs less than the stock buick 215 flywheel. That's a good thing in our cars.


Samy, What fuel system are you using?
I was under the impression that the 4.0 engine as opposed to the late 3.9 was a distributorless injected engine that has a sensor which reads information from a "target" on the flywheel.
Of course if you have converted to an earlier FI/ignition system or carburator with distributor you wouldn't require the dizzyless flywheel and you could use one of the aftermarket units.
I have a 4.0 with a manual flywheel which includes the target. And at forty three pounds is quite a chunk of metal.

Regards, Dick Shaler
richard shaler

If you're using a distributor set up it might be cheaper to have your flywheel machined. If you take about half an inch off you get down to Rover sedan/MG weight & that might be enough to remove the groove.
I don't know if machining is possible with the distributorless set up, I've no experience with these but I can't see a problem if you ovoid removing the target.

I'm not familiar with the engine, so this might be an issue, but make sure you have a pilot bushing in the end of the crank to receive the snout of the manual box propshaft. Cheap - maybe a few bucks, there may be one in there already, but it is a little detail that you don't want to overlook.

Brian C.

72 bgt
3.4 injected V6 w/T5 in progress
Brian Corrigan

I never heard of anyone making a flywheel from a flexplate. Maybe it's possible in some situations.
Glenn Kendall

I have.

If a flex plate is the only piece available. Fit a piece of steel centered on the flywheel large enough to accept the pressure plate, cemnter it on the flexplate, and turn the inside diameter and outside diameter of the chunk of steel.

The application I saw used a solid disc brake rotor bolted to the flex plate.

Keeps weight in toward the center of the crank, so the polar moment of the 'flex-wheel' is low for quick revving
Greg Fast

Dick (and everyone else),
I am trying to use the original fuel injection that came with the car. The Bosch distributerless. I travel Monday thru Friday and don't have time to make this car so I took it to my Rover mechanic for him to work on. He did mention about the grooves in the back for the "target" Where can I get a manuel one (rather than having the automatic one)?
Thanks for the help.
Samy Cuzmar

If a 2000 Disco came with a stick transmission, you should be able to get the appropriate flywheel with timing sensors in it from a Land Rover Dealer
Greg Fast

Hi guys,

I have a 2001 Disco with a rover 5 spd box so they do make them. Your issue Samy will be the new induction system on the series 2 disco is different and I think bigger than the old induction system. May be hard to get under the hood. The other issue will be the adaptive learing ECU which I believe will have transmission sensors, rev limiter, etc etc. I don't know how good your mechanic is but the ECU would need some serious analysis to adapt to the MG.


Is it possible to put in a different induction system and ECU for that engine or should I sell the engine and look for a different one?
Samy Cuzmar

The induction from a 3.9L range rover will bolt right on. You'll have to use a buick timing cover, and preferrably a buick front pulley, but it will all bolt up with minimal hassle. You'll also need the range rover OR buick 215 oil pan. Nothing out of the ordinary there though.

I'm still investigating running a ford fuel injection system in my car, but I'm going to wait till after I play with my motors this winter before deciding what to do.



This thread was discussed between 09/12/2003 and 19/12/2003

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