SPi and MPi Mini Flywheels Updated

Our latest evolution of the MED SPi and MPi Mini flywheels are now complete and ready to go. These are designed for Rover Minis, 1991-2000, which had fuel injection from the factory, and used a reluctor ring on the back of the Verto-style flywheel to work a crank position sensor.

You may have noticed these have been offline for a while, as we have redesigned the EN8 lightweight steel flywheel to include an integral starter motor ring gear, as with our latest Verto steel flywheels.

We've been working on some specialist heat treatment work to the teeth - essential when the ring gear is CNC'd in - which we've achieved without distorting the flywheel. That's the very tricky bit, as the flywheels are lighter than standard, with a large hole in the centre for good measure.

The new flywheels can be built into a superbly balanced assembly with extra torque holding ability, and without the separate reluctor ring, which can move and cause running issues on late-model Rover Minis.

For reference, MPi Minis have four gaps in the reluctor ring teeth for the wasted spark coil pack firing, and SPi Minis run just two. European-spec MPi Minis were built from 1996 to 2000 and can be identified by a front-mounted radiator and lack of distributor.

SPi Minis were earlier, 1991-1996, and have a side-mounted radiator. If you have a post-1996 Japanese export Mini, these usually have an SPi style flywheel - but count the number of missing teeth on the reluctor ring to be certain.

https://www.med-engineering.co.uk/collections/injection

Stephen Colbran

February 2026