Fitting Guide

MED ST1 ULTRA LIGHT STEEL F/W ASSEMBLY

Name: MED ST1 ULTRA LIGHT STEEL F/W ASSEMBLY
Brand: MED Engineering
SKU: MED-4110-ULP
Price: 475.0 GBP
Availability: InStock

Part No: MED-4110-ULP

£475.00 £395.83 EXC VAT

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Availability: In Stock

Description

The MED Stage 1 Ultra Light Assembly includes an EN8 steel flywheel, backplate and performance road clutch. It's the ideal setup for fast road Minis producing up to 80lb.ft torque.

The package is expertly assembled, centralised and dynamically balanced to order.

Assembly contents:

MED EN8 Ultra Light steel flywheel - 3.66kg.

MED EN8 Ultra Light steel back plate - 1.32kg.

Performance road clutch plate.

Blue clutch diaphragm.

9x MED clutch drive straps.

6x MED EN16T steel drive bolts.

Fully assembled and centralised in-house with dynamic balance.

Flywheel Specification

The MED Ultra Light is CNC machined from EN8 billet and weighs just 3.66kg, a substantial saving compared to standard factory flywheels, which can weigh over 7.5kg! In fact, the complete St1 assembly weighs less than the standard flywheel alone, at an impressive 6.5kg.

Reducing flywheel mass improves the Mini's acceleration considerably, more so than the weight loss alone.

As a result, installing the MED Ultra Light kit will make the car accelerate faster, feel more responsive, and is one of the most cost-effective performance upgrades you can make.

This flywheel can be supplied with a 107-tooth inertia ring gear to suit early style starter motors, or the later 129-tooth pre-engaged design, which is CNC machined into the flywheel itself as per the EN24T X-Lite.

Alternatively we keep High Torque Starter Motors to match.

To install without disturbing the balance, remove the large washer and spring clip from the diaphragm and there is no need to disassemble the clutch/flywheel to install the bolt.

Moving to the St2 Ultra Light package upgrades to a stronger clutch plate and diaphragm.

Due to the nature of the heat treatment process, the colour may vary slightly from the images.

Please see the Additional Information tab for further advice.

Additional Information

Flywheel compatibility

Upgrading to an MED steel flywheel not only saves weight, but also gives a more durable surface on which to grip the clutch plate. The lighter the flywheel, the faster the engine will be able to increase/decrease RPM, making it more free-revving and responsive to throttle input.

Our lightest possible clutch and flywheel setup (X-Lite) is ideal for a competition car, whereas a road car will benefit from more flywheel mass to retain drivability in traffic.

The MED EN8 Ultra Light is therefore an excellent choice for performance road and trackday cars - lighter than standard yet still usable on the road. It is also the choice for Mighty Mini and Mini Se7en S-Class race cars.

This flywheel will suit all transverse A-Series engines (Mini/Metro) with a pre-Verto clutch setup. It is possible to convert from Verto to pre-Verto by purchasing the MED Heavy Duty Clutch Operating Kit. Please note - this will not suit fuel-injected Rover Minis. See the MED SPi Flywheel or MED MPi Flywheel for these cars.

Pre-engaged or inertia?

This relates to the ring gear and starter motor installed on your Mini. Inertia is the original style starter motor that uses a separate solenoid unit on the inner wing, whereas pre-engaged has an in-built solenoid. If you have one of our High Torque or Micro starter motors, simply choose the correct flywheel to suit.

For reference, pre-engaged flywheels have 129 teeth on the ring gear, inertia types have 107 teeth.

Alternative options

The later Verto system introduced in the mid-1980s makes a good alternative for a performance road Mini. This design gives an easier clutch pedal, which might be preferable for daily drivers, however the overall assembly does weigh around 2kg more.

The MED X-Lite Flywheel is the best alternative for full competition Minis, featuring larger cut-outs and an integral ring gear for the starter motor. It is also machined from a higher grade of steel, so has less chance of fretting on the taper of a competition EN40B steel crankshaft.

Fitting advice

We would highly recommend purchasing a complete balanced flywheel assembly and fitting it in one piece to retain the balance. You may wish to lap the flywheel gently to the crankshaft taper before fitment, being careful to remove all traces of paste before final installation.

Firstly lock the engine in position with a Mini flywheel locking tool. Torque the MED pre-Verto flywheel bolt to 130lb/ft, to seat flywheel on the crankshaft taper.

Now undo the bolt, apply a drop of standard-grade thread lock to the thread and re-torque to 130lb/ft. This will ensure the flywheel is properly seated on the crankshaft taper.

Frequently Asked Questions

Which ring gear style do I need?

The inertia style suits the original Mini starter motor, as fitted from 1959 to around 1980, when the Metro was introduced and starter motors began to transition to the more modern pre-engaged design. As a quick reference, the inertia starter motor has a separate solenoid unit and the ring gear has 107 teeth. The pre-engaged starter has an in-built solenoid and will engage with a 129-tooth ring gear. If you have purchased one of our high-torque starters, simply match the two together.

Is this for 998 or 1275 Minis?

Either - this will suit any classic Mini engine from 998cc to 1275cc with the pre-Verto clutch system. This will also suit 850cc Minis, excluding the very early cars with a 'thin tail' crankshaft - quite rare today. For reference, these measure 1.375" at the start of the crankshaft taper, rather than 1.5".

What's the performance advantage of this kit?

Upgrading to an MED steel flywheel kit saves weight, and gives a more durable surface face on which to grip the clutch plate. The lighter the flywheel, the faster the engine will be able to increase/decrease RPM, making it more free-revving and responsive to throttle input. In addition, we very carefully assemble, centralise and balance within a gram, for a smooth-running engine.

Will this flywheel increase the power of my Mini?

No, changing the flywheel has no effect on the power output of the A-Series engine, however it does increase responsiveness and acceleration by reducing rotational inertia. Reducing weight from the flywheel in particular has a far greater impact on acceleration of the Mini than weight loss elsewhere, so is highly recommended for all performance Minis.

How much power will this hold?

We measure this as a torque figure rather than BHP, and on our static rig, a brand new assembly will hold around 80lb.ft before starting to slip. Once the clutch plate is carefully bedded-in, this figure will increase slightly.

Is this suitable for road use or competition?

Most St1 kits are used in high performance road-going Minis, but this could also be used in a competition Mini if the engine torque figures allow. Typically we would move up to the St2 kit for more strenuous trackday usage, or for Minis with 90+bhp.

How long does it take to build and dispatch this kit?

We try to keep a couple of each variety built up ready on the shelf, but if not, we can usually turn these around within one working day.

How does this compare to a standard Mini flywheel?

These are machined from certified EN8 steel billets compared to the cast iron originals. As a result, we can reduce the overall weight far more than is safely achievable on a standard flywheel, which are brittle in comparison. The ring gear teeth are also machined into the steel, then specially heat treated, for much improved longevity.

Do you have any fitting or bedding-in instructions?

Yes, each kit is supplied with a tech sheet, which can also be downloaded in PDF format, above.

Can I fit this on a later Mini with a Verto flywheel?

Yes, so long as the Mini does not have fuel injection, you can convert to the earlier style relatively easily. We can help to make the conversion easier with our clutch arm kit, part number MED-4810-HDK.