GEARBOX - Final Drives, standard

FDs are ultimately responsible for the way your Mini goes after engine, gearbox, and under carriage tweaking has been applied. part numbers: DAM3647, 22G443, 22G101, 22G340, 22G338, DAM4131, 22A399, DAM4162, 22G940, 22A399, DAM2677, DAM2679, 22A411, 22A413, DAM2808, DAM6327, DAM2808, TCC10001, Terminology - FD - Final Drive/diff ratio The aforementioned and the degree to which it has been done will affect the decision as to what FD is required. They’re also responsible for much discussion between many tuning freaks, and confusion to the less informed. There’s nothing weird or scientific about it. Maximum acceleration requires a low final drive, top speed a high one. And these two terms confuse most. The confusion being the LOWER number denotes a HIGHER gear. Likewise the higher number denotes a lower gear. Likewise the higher number denotes a lower gear. Largely because the lower the ratio, the slower you go and vice versa.

Gearbox - Fomulae for FD/Tyrespeed and Gear Ratio Calculation

Basic rule to remember is ratio is established by dividing tooth count ondriven gear by the tooth count on its driver. To work out overall gearbox ratios you also have to establish the constant ratio.

Terminology -
FD - Final Drive (diff ratio)

Formula : 60,000 FD (Final drive/diff ratio) x wheel rev per mile.

Calculation for establishing vehicle speed for different final drives.
Formula These are for common tyre types, and accurate enough for assessment - a combination of using industry standard for theoretical calculation, actually measured assortment of wheels/tyres, and calculated averages! Applying

Cooling - Controlling water temperature

The introduction of the Cooper S proved to be a testing time for the Mini’s systems, but conveniently provide a guideline as to what the standard cooling system was capable of - that used on the ‘S’ was marginal to say the least!

It wasn’t uncommon for many S’s to spew water from their overflow pipes when ever it was doing anything other than a steady 70 miles an hour, over-heating eventually caused through water loss. Perhaps some deductions can be made from the following…

There are a number of elements involved in controlling water temperature. Some confusion over what to sort first when over-heating occurs leads to wasted time and money, and possibly terminal engine damage. Maximum power is usually generated from A-series engines at 70 – 75 degrees C (160 to 170 degrees F). The main problem with this on a road car is the oil’s unlikely to get hot enough for maximum performance – the results outlined previously.

Distributor - Initial ignition timing set-up.

Any deviation away from the original standard engine specification, or where a dizzy from another source is used in the engine you have, the ignition timing will generally be different from that set by the manufacturer.

Terminology -
Dizzy - Distributor
TDC - Top Dead Centre
BTDC - Before Top Dead Centre
ATDC - After Top Dead Centre
CR - Compression Ratio

Tacho - Tachometer, rev counter (not to be confused with Mexican food delicacy!)
Vac - vacuum (pipe, unit, etc.)

Any deviation away from the original standard engine specification, or where a dizzy from another source is used in the engine you have, the ignition timing will generally be different from that set by the manufacturer.

Gearbox - Formulae for FD/tyre size/car speed and gear ratio calculation

Calculation for gear ratios and transmitted engine rpm Basic rule to remember is ratio is established by dividing tooth count on driven gear by the tooth count on its driver.

Basic rule to remember is ratio is established by dividing tooth count ondriven gear by the tooth count on its driver. To work out overall gearbox ratios you also have to establish the constant ratio.

Terminology -
FD - Final Drive (diff ratio)

Calculation for establishing vehicle speed for different final drives.
Formula :                               60,000 
                    FD (Final drive/diff ratio) x  wheel rev per mile.

MINISPARES HISTORIC RALLY TEAM - 2005 SEASON - PART1

After a major engine rebuild carried out by MED in Leicester designed to give a stronger bottom end with a fully specified crankshaft and their special high torque camshaft (STR 930) to make the car more driveable.

The S rods were smoothed, polished and whole assembly balanced giving a very usable power band from 3000 to 7000, but capable of revving to 8000 safely.

MINIS ON THE MANX 2008 - RETURN OF PETER HORSBURGH & ‘277 BRX’

At long last the successor to my stolen rally prepared Austin Cooper S, 277 BRX, has emerged from a 12 month rebuild of another Cooper S I bought in 2007. This car is a Morris Cooper S first registered in 1965 and converted into a 60’s rally replica, but not prepared to the current regulations for special stage rallying, and is now stored off-site for obvious security reasons.

Despite my knowledge of old minis...

Snetterton - Never Say Never - Jonathan Lewis

I had been dreading my home race for a few reasons, one I did not feel that I had the car to win it this season and the second was we have been so busy with caravans at Snetterton Speed Shop, hiring Caravans out as well as selling them, I had not given much time to my Mighty Minis as they deserved.

Cylinder head 2022

Minispares Offical Stockist For Revolution Wheels