Engine - 998 Tuning, Bolt-ons

The 998cc engine is a very robust and tunable unit. It is also the most common engine found in standard Minis. See bottom for useful part numbers Terminology: MSC/MM - Mini Spares Centre/Mini Mania ID - Inside Diameter OD - Outside Diameter BBU - Big Bore Unit (refers to all 1275cc-based units) SBU - Small Bore Unit (refers to all sub-1275cc units, here the 998) BHP - Brake Horse Power LCB - Long Centre Branch Despite the lure of the much-advertised 1380cc alternatives, many simply want to get a little more from what they have at reasonable outlay. The single biggest restriction on any standard Mini is the 'breathing apparatus' - anything that is connected to the induction and exhaust systems. The standard exhaust being the biggest culprit - it is desperately restrictive in the name of noise suppression and cheapness of manufacture. Oddly enough it also increases fuel consumption when tested over a better designed, fre

Winter is coming.........

Cold running and why tuned Minis simply quit running when pulling up.

Winter is coming, and with it various issues that affect Minis used throughout the year, no matter what the conditions.

This month's consideration is cold running and why a plethora of tuned Minis simply quit running when pulling up. Ignoring the few that are down to various other ailments, the main issue is just the cold weather. Those that suffer more ...

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.

Cylinder head - Min Tec head range

I'm often asked about the range of cylinder heads I do for Mini Spares/Mini Mania, so here's the low-down…

Although the following range of heads accommodate specific fitments - like pre-1992 where by-pass hoses and heater take-offs on the clutch end of the head are used and post-1992 where neither of these exist, and on SPi (single point injection) heads where they don't usually have a threaded hole for the temperature sender - in reality it is easy to convert almost any of them to fit any other engine since holes are easily blocked off - or by-pass hoses not used, water pumps blanked off and drilled thermostats fitted (see articles on cooling/engine transplants). A list of which is what and what to do to each to convert is at the end of this article.

For more in-depth descriptions of the head specs, see article 'Cylinder head - About Min Tec Heads' - basically the valve sizes used have been decided on after extensive and in-depth flow test...

Engine - 998 tuning, bolt-ons (stage one)

The 998cc engine is a very robust and tunable unit. It is also the most common engine found in standard Minis. Despite the lure of the much-advertised 1380cc alternatives, many simply want to get a little more from what they have at reasonable outlay.

Terminology:
MSC/MM - Mini Spares Centre/Mini Mania
BBU - Big Bore Unit (refers to all 1275cc-based units)
SBU - Small Bore Unit (refers to all sub-1275cc units, here the 998)
BHP - Brake Horse Power
CR - Compression Ratio

To improve engine out-put, you need to increase the engine's 'breathing' ability. The stage one kit deals with all the easily bolted-on external parts, and represents the best increase for investment. From here on in the power increases will cost commensurately more money.

Engine - 998 tuning, further options

Following on from the easily bolted on performance enhancing components out-lined in the stage one section, we need to consider where to go to get more power output.

Terminology:
MSC/MM - Mini Spares Centre/Mini Mania
BBU - Big Bore Unit (refers to all 1275cc-based units)
SBU - Small Bore Unit (refers to all sub-1275cc units, here the 998)
BHP - Brake Horse Power
CR - Compression Ratio

To improve engine out-put, you need to increase the engine's 'breathing' ability. The stage one kit deals with all the easily bolted-on external parts, and represents the best increase for investment. From here on in the power increases will cost commensurately more money. Power production of any engine, once the 'breathing apparatus' (induction/exhaust system) has been dealt with to cause no restriction ...

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.

Engine transplants - Ancillary parts

Engine mountings are a whizz to fit as the Mini ones fit straight onto any of the other units. Just remove the Metro/AA/1300GT ones and swop the mounts over from the Mini unit. If they’re split, fit new ones, they’re cheap.

Terminology -
BBU - Big Bore Unit
SBU - Small Bore Unit

NOTE: This information covers transplanting large-bore engine units into small-bore engined Minis. For further information for exact differences between pre-A+ and A+ units, see relevant separate article.

Engine mountings and steady bars.
Engine mountings are a whizz to fit as the Mini ones fit straight onto any of the other units. Just remove the Metro/AA/1300GT ones and swop the mounts over from the Mini unit. If they’re split, fit new ones, they’re cheap. If using the AA/1300GT unit - it's advisable to cut off the 'wings' on the front plate that carried the engine mounts on the radiator end.

Engine transplants - initial information and engine choices

Is this familiar? - You take the small one out; you put the big one in. In, out, in, out, shake your fist about, you do the hokey-cokey and you turn around, that’s what it’s all about...

Terminology -
BBU - Big Bore Unit
SBU - Small Bore Unit
Bodge - English term for 'make do' engineering- assured to fail at an in opportune
Moment.
Dizzy - Distributor

NOTE; this information is largely for transplanting large-bore units into small-bore engined cars.

Is this familiar? - You take the small one out; you put the big one in. In, out, in, out, shake your fist about, you do the hokey-cokey and you turn around, that’s what it’s all about...kinda sums up the situation many folk find themselves in when attempting to endow their beloved Min with a more impressive turn of speed.

MINI ENGINE STABILISER MSSK1000

1. This is an auxiliary steady bar kit and should not be used to replace any other standard fitment parts that have broken.

2. Remove the radiator support bracket from the radiator and the thermostat housing.

3. Slacken the nut retaining the exhaust manifold at the radiator end of the engine.

4. Remove the three bolts securing the bulkhead blanking plate as shown in the diagram. If the car has a heater pipe as indicated on the diagram then this should be disconnected at the engine.

MINI ENGINE STABILISER MSSK1300

1. This is an auxiliary steady bar kit and should not be used to replace any other standard fitment parts that have broken.

2. Remove the radiator support bracket from the radiator and the thermostat housing.

3. Slacken the nut retaining the exhaust manifold at the radiator end of the engine. Remove the exhaust manifold stud by tighterning another nut against the original manifold nut and then screwing the nut out of the cylinder head.

4. Remove the three bolts securing the bulkhead blanking plate as shown in the diagram. If the car has a heater pipe as indicated on the diagram then this should be disconnected at the engine.

05.06.10, Brands Hatch race report by Keith Calver

I am not sure why, but I don't really enjoy Brands Hatch. It is a quite technically difficult circuit to set fast lap times on. It is most definitely one of those circuits that 'be slow to go fast' applies to.

You can not hustle or hurry it. I am speaking from the point of view of having to use treaded tyres that don't give a tremendous amount of grip. And probably a circuit where 'loose is fast' applies... but I am still building confidence.

Cylinder head 2022