15 replies to this topic

[Bobbins]

Any ideas as to which Verto flywheel is used in a '98 JDM Mini, 2 or 4 missing teeth pattern? A '98 JDM is distributorless so I'm thinking it'll be the MPi version, even though it's got the SPi throttle body?

 

 

[Bobbins]

Anyone?

[Wiggy]

I'd guess MPi too. Not too much bother taking the starter off and having a look.
Bit more of a pain for a UK MPi, because you have to unmount the radiator.

[Bobbins]

True, maybe that's a good place to start :)

[FlyingScot]

True, maybe that's a good place to start :)

If you do please post up!

FS

[Bobbins]

I will!

Please moderators can we have a JDM section for this sort of info!!!

[hungdynasty]

 The JDM uses a coil pack and a cam sensor so I would think MPi.

Actually my JDM uses a coil but no cam sensor.

[viz139]

 

 The JDM uses a coil pack and a cam sensor so I would think MPi.

Actually my JDM uses a coil but no cam sensor.

 

Sorry ,just checked the wiring diagrams and I stand corrected . So I would now think SPi.

[tmsmini]

According to Somerford, if you have the coilpack, then you have this flywheel:

http://www.somerford...age=page&id=143

 

 

GCU90123AF FLYWHEEL AND CLUTCH ASS'Y, balanced 1 1997 on; for MPi (multi point injection) fitted 1275cc models plus SPi (Japan). GCU90123AF FLYWHEEL AND CLUTCH ASS'Y, balanced 1 1997 on; for MPi (multi point injection) fitted 1275cc models plus SPi (Japan).

[viz139]

 

 The JDM uses a coil pack and a cam sensor so I would think MPi.

Actually my JDM uses a coil but no cam sensor.

What year is your car?

[hungdynasty]

 

 

 The JDM uses a coil pack and a cam sensor so I would think MPi.

Actually my JDM uses a coil but no cam sensor.

What year is your car?

 

1998 JDM

[FlyingScot]

Did we find an answer to this?

I had a 1996 Anniversary JDM with normal block, head and coil with SPi injection unit. Standard Cooper ECU.

 

I am building a 1997 Cooper which has MPi style block and head, SPi injection unit and specific ECU and wiring loom, but which flywheel? ( I don’t currently have a flywheel for it hence the question).

i can guess as good as anyone (maybe even better) but would like if possible factual confirmation of SPi or MPi flywheel used in these.

 

FS

[Bobbins]

My distributorless '98 JDM has the Mpi flywheel.

I concluded that the MPi flywheel is needed when there's no dizzy so that the ecu knows when to fire the spark plugs, i.e. only at the top of the stroke (wasted spark), whereas the SPi flywheel is used in the earlier setup with a distributor which uses the camshaft to determine the firing at the top of the stroke.

The injection is not relevant because in the SPi with only one injector it needs to open 4 times per revolution irrespective of which cylinder is on which stroke.

[FlyingScot]

My distributorless '98 JDM has the Mpi flywheel.

I concluded that the MPi flywheel is needed when there's no dizzy so that the ecu knows when to fire the spark plugs, i.e. only at the top of the stroke (wasted spark), whereas the SPi flywheel is used in the earlier setup with a distributor which uses the camshaft to determine the firing at the top of the stroke.

The injection is not relevant because in the SPi with only one injector it needs to open 4 times per revolution irrespective of which cylinder is on which stroke.

Makes sense and thanks for confirming. Guess I’ll need to find an MPi flywheel now for my build 

 

FS

[Wazzah]

The simple way to think about this topic is that all injection JDM's are SPI's.

Rover bolted on the SPI equipment on whatever engine block/ head was current for that year model.

Pre 97 had distributors in the usual place and are basically the same as the UK market version.

When the MPI was produced in late 97 Rover made changes to the block with the main one being to the distributor hole.

In the MPI the oil filter was relocated to this former distributor position.

Their camshafts do not have a distributor drive.

A wasted spark ignition system was also part of the MPI upgrade and this was fired from a sensor that picked up a 36-4 notched flywheel mounted timing ring

There are 2 notches on the flywheel 180 degrees apart to signify the 2 Top Dead Centres.

The other two notches lag each of the TDC's. (or lead, whatever)

One is located 2 notches from one TDC the other 3. (It may be 1 and 2 and I could open my new MED Flywheel box to verify)

The staggering of the notches tells the ECU which cylinder is at TDC.

The post 97 JDM's mirror this wasted spark/ flywheel system.

The MPI's only had an additional camshaft sensor that runs of a lobe of the camshaft where the fuel pump used to go.

The JDM's do not have or need this additional camshaft sensor.

The MPI's having a separate injector on each inlet runner had a unique firing sequence where the same injector is fired once then quickly again to solve the port robbing issues of every 5 port mini.

This camshaft sensor was the only way of achieving this unique injector firing.

The SPI's don't need this feature due to a single injector pumping fuel into a shared location in a wet manifold.

Clear as mud.

So why did the Japanese want single point injection?

They didn't but they did want to an automatic transmission option.

The lost motion linkages on an SPI throttle body was the easiest way to install a kick down linkage for an auto gearbox.

There were no auto MPI's.