Distributor - Electronic Ignition

Since the A-Series has such an efficient combustion chamber design, the standard points set-up is perfectly capable of providing sufficient sparks for effective combustion when new. And this is the problem. They require regular servicing to maintain maximum performance. This can be a chore, so is generally neglected. And it doesn't take long before deterioration seriously affects performance. Points bounce is also a problem on high-revving race motors.

Deterioration of the points set-up can be caused by several factors - wear and tear on the dizzy spindle bearings creating 'wobble', electrical erosion of the points, and wear of the points cam heal. All have the same effect - dwell angle alteration. This in turn reduces spark effectiveness. The consequences are a loss in power and economy, poor starting performance, and general poor running.

Engine - 1098, Initial Tuning

The 1098 (1100) engine has had a lot of bad press over the years - largely because of early experiences when trying to tune the motor brought about problems with the then standard components available - they simply were not up to taking any real punishment as experienced in racing.

See bottom for useful part numbers.

This fallacy was handed down generation to generation like some scary bedtime story. Those that have used the unit in more recent years, employing more capable componentry know what a demon motor this can be. Following is an initial look at what it will do with a little modification - the results compared directly with it's smaller brother the 998 for illustration of the potential.

Abridged History
When the Mini was first conceived it ustilised a de-stroked version of the then quite remarkable 948cc A-series engine.

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.

Distributors - Modifying them, how, where, and who

When a known engine build formula is used, dizzies can be churned out with the relevant advance curve to suit - as in standard production engines. Terminology - Dizzy - Distributor When a known engine build formula is used, dizzies can be churned out with the relevant advance curve to suit - as in standard production engines. Reading the 'dizzy working basics' article defines what the dizzy does and how. It's pretty obvious then that any changes at all in the original engine specification is likely to require a different advance curve. This is where most folk fall down when completing the ‘build for power’, by assuming that an alternative dizzy from a sportier or similarly powered engine will do the trick.A simple illustration is folk's preoccupation with sticking a 'S' dizzy into anything tuned in the belief this is the way to go. It's not. It's likely to be as useful as the one you have.

Engine - 1275, 95bhp sports/tourer test result

DIY enthusiasts often believe that building an engine to give excellent all-round road performance is beyond them. Mainly from comparisons made between what they have been able to achieve and what specialists say should be achievable from any particular type of engine build.

Generally scrambled further by the non-perfect match of parts and components used between aforementioned specialist and erstwhile DIY-er, and the ritual 'nose-tapping and knowing winks' display of those specialists. Something you can very nearly 'see' even when talking to such folk on the phone - or that inimitable 'ah, yes, well…' So some form of 'black art' is implied. Whilst there is most definitely a degree of 'feel' involved between the real specialist's results and those of just a good engineer - the bones of the deal is subject to no such thing and is certainly within the capability of the DIY enthusiast given the necessary information. And that has been the problem.

Exhausts - RC40, Millennium and others tested

The recent rolling road re-test of the 1275 engine build I did saw an opportunity to do some exhaust systems testing.

I had noticed a few years back that the RC40 was being manufactured by a different process than the originals - giving rise to a change in the shape of the bends applied to the system. I had wondered if they would be causing a restriction at all - but hadn't had the opportunity to test it. The lack of expected power from the aforementioned engine lead me to investigate all possible angles from the tyre contact patch to the carb mouth. I found nothing that explained the 14 or so bhp I was 'missing'. After some application of the old grey cells I mentally narrowed cause down to one of two things - either the piston oil control rings were still causing excessive drag (75% of all internal friction of an engine is generated by the piston rings) or perhaps these new bends in the venerable RC40 were indeed causing a power loss.