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To scatter or not to scatter, that is the question. This whole 'scattering' deal has befuddled many. The only real prose produced on the subject, and 'advice' handed out by many so-called 'specialists' tends to be somewhat tainted with large chunks of mysticism - inferring there's some kind of black art involved. The simple fact is the principle is very basic and easy; it's getting a cam with the right profile and figures applied to it that will actually work as a scatter profile that's the hard part. And this article does not mean I am all for scatter pattern cams. I will illuminate… We are all pretty much aware that the A-series is a real oddity, largely because of the siamese (shared) port work - cylinders 1 & 2 share an inlet port, cylinders 3 & 4 share an inlet port, and cylinders 2 & 3 share an exhaust port. Very weird compared to the more familiar head designs found on almost every other engine type that has one inlet and one exhaust port per cylinder.

Camshaft Design

Elgin Cams is a company that is a direct descendent of such famous California specialists as Isky, Delong, Winfield, etc. etc. Elgin has taken the art of cams into the science of the '90's. Computer designed and handcrafted workmanship guarantee a first class camshaft. Custom designed cams are a specialty. Part No Applications: CAM001, CAM002, CAM003, CAM004, CAM005, CAM006, CAM007 Elgin has made cams or sold his design to General Motors, Ford Motor Co., Nissan Corp., Zakespped International, Porsche Motor Sports, Winston Cup "Engine Builders. Elgin has the largest percentage of cams used at the SCCA Runoffs from GT-1 to Formula-V. He also has provided original or new technology for antique and vintage racers. Much information has been recorded about the four stroke internal combustion engine and yet only a small percentage of people really understand how it works and fewer people know how to modify an engine to suit their needs.

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.

During a discourse with the editorial staff at Mini Mag, it was decided the build feature presented an ideal opportunity to demonstrate just exactly what such an engine build is capable of in days where it's generally believed you have to have an all-singing, all-dancing 1380cc engine to have an enjoyable road burner - leaving those with very limited budgets a little depressed. During a discourse with the editorial staff at Mini Mag, it was decided the build feature presented an ideal opportunity to demonstrate just exactly what such an engine build is capable of in days where it's generally believed you have to have an all-singing, all-dancing 1380cc engine to have an enjoyable road burner - leaving those with very limited budgets a little depressed. So the idea was to finish the engine off using a relatively 'mild' specification to maximise drivability. The camshaft used was the fantastically versatile Swiftune Racing SW5 profile that provides drive from nowhere up to 7,000rpm - d

Rocker gear - General compendium

Whether you’re building a solid road performer or fire-breathing monster, the main goal is to improve air/fuel flow into the engine. The more you can get in, the more power you can get out. Cheapest chunk of power improvement comes from sorting the asthmatic manifolding and exhaust by applying a stage one kit. Then what? Considering the ‘get more in to get more out’ theme, the main restriction - all else being equal - is the valves and their behavior. How big they are, how efficient they are and how long they’re open for determines how much gets in with each gulp each bore/piston makes. Modified cylinder heads are popularly next, although it has to be said that although a well modified cylinder head will improve performance, the gain against cost is nowhere near that given by the ‘stage one’ kit application. A good stage one kit’s improvement verses cost is around £12.50 per 1 hp, a decent modified head typically £30 per 1hp - dependent on application. Hmm.

Engine - Identification Data Updated

If you have the engine tag still attached to the engine - just in front/below the thermostat housing - or perhaps the original engine number in the log book then the following should help you determine which engine you have. For Metro units, see 'Engine - Metro identification data'. Original engine identification numbers 850cc 8A Austin up to 25000 8MB Morris up to 25000 8AM Austin & Morris 25000 onwards 8AH Austin & Morris Automatic 8AJ Austin & Morris closed circuit breathing 8AK Austin & Morris automatic with closed circuit breathing 8WR Wolseley Hornet & Riley Elf 8AC Moke 85H/101 All variants 1969 onwards Note: third suffix letter denotes compression type, L = Low, H = High, e.g. 8AM/U/H101 denotes high compression. 998cc 9WR Wolseley Hornet & Riley Elf Mk2, pre closed circuit breathing 9AD Austin, Wolseley Hornet & Riley Elf Mk2 with remote type gearbox and closed

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.

Valves, guides and springs.

Concerned about fitting up-rating parts to injection engines? A short while ago I had several conversations via e-mail with folk abroad who were a little concerned about fitting up-rating parts to their injection engines - like one of the many 'GSi' tuning kits available. A rumour had been put about that fitting this kit caused engine damage. Closer questioning culminated in the rumour saying that the high lift (1.5 ratio) rockers were causing camshaft and valve/guide damage. You know me - I can't let things like this alone until I find out the root cause. After some more digging and goading, I believe I've found the problem.

Cam damage is usually caused by something amiss in the valve train - obviously. Since the engines concerned were as they came from Rover and had done many thousands of miles without issue, it had to be something to do with these kits.

Valves, guides and springs.

The red lights went out after a short wait and the 2005 season was underway. I held position and went early on the attack,

It seems remarkable, but a winter break of over six months is never enough time to prepare a racing car! The truth is, at long last I've completely refurbished the hall, stairs and landing at home. That concludes a 7 and a half year ...

I recently had one of my best mates to stay for a week. Don't get to see him very often, so when we're together we spend most of the time pontificating on all things A-series since he's a long-time Mini enthusiast too. Well, at least from a racing point of view. Anyway, of the various subjects covered one that prompted me into doing this little piece of verbiage was that of compression ratios (CR).

It's another for those subjects where folk can be heard waxing lyrical about their personal recommendations for CR levels, or stipulating hard and fast 'facts' about CR required for certain camshafts. And again, it's one of those generally misunderstood areas of engine tuning. So I'm going to try and cut through the haze a bit.

CRs are generally spoken about and quoted in reference to the 'static' ratio. That is a bunch of calculated or measured volumes calculated by means of an equation.

A+ head castings - despite having the same 12G940 casting number - are considerably different in appearance, loosing the flat area behind the thermostat housing and around the rest of the rocker/head stud areas to a sculptured look - where these areas are replaced by a 'sunken' cast finish. The A+ castings were introduced with the appearance of the Metro in 1980, although some late 1275GTs (1979-on) had them fitted. Generally they are easily recognised by their colour - a putrid yellow on the small-bore castings and bright red on the large-bore ones, a paint finish that is VERY difficult to remove, even in a chemical tank. The MG

See bottom for useful part numbers.

Cylinder head - Suitability basics

Whatever else owners do to their Minis by way of interior/exterior modifications or none at all, a very large proportion desire and search for an increase in engine performance.

See bottom for useful part numbers.

Now this may not be super-sonic speed-inducing power, it could just as well be for maximum economy. In either case, it's the engines volumetric efficiency (VE) under scrutiny - it's ability to breath in as much correctly proportioned air/fuel mix as possible in any given situation. Although the induction/exhaust system plays an important part, there are effectively two major factors that dictate performance increases - the camshaft and cylinder head. The induction and exhaust elements (stage one kits, exhaust systems, etc.) and camshafts are covered in various other articles in my 'Corner'. So here we'll have a look at cylinder heads and dispel some of the myths and legends surrounding them.

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 ...

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 - Identification data

The widespread and prolific fitment of Metro engines into Minis - usually those endowed as standard with small-bore (850/998/1098) engines - practiced in the UK has been spreading to many other countries worldwide.

So it's not surprising that the most commonly asked question has also become more prolific concerning the fitment of said engine - apart from actually how to manage the transplant and the differences in the installations, covered in articles relevant article on this site - is just which type of engine the individual concerned has bought or what they already have fitted to their car and is it worth keeping or junking. One initial question I pose often draws a pregnant silence whilst said inquiree scrambles their brains trying to find an answer for. Following that protracted pause, 'I dunno' is the usual answer. I then have to get into a lengthy explanation as to how to determine what said engine is.

There is no specific large-bore (1275cc-based) head casting number that will fit the 998 engine any easier than any other.

They all have the same problems - generally requiring exhaust valve relief cut-outs machined into the block and re-alignment of the front water gallery transfer ports. However, I would avoid using heads with valves bigger than 35.7mm on the intake since these are too big for most 998 engines unless they are absolutely full-race spec where top end power at high rpm is all that is required.

First of all it is worth checking that you actually need to make the relief cut-outs since some heads have a big enough head face to exhaust valve face clearance to allow fitment without the cut-outs when the standard cam and rocker gear is retained.

If possible, measure the actual valve lift you are getting with the current fitted set-up.

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.

Lubrication - Oil pumps

Essential to the well being of every engine is its oil pump and oil. Much in the same way as the heart and blood is deemed relatively important to us humans! It's also another of those greatly misunderstood and, unfortunately, misrepresented subjects connected to engines.

An alarming number of so-called A-series engine specialists would have you believe that once parting with a veritable bundle of your hard earned readies on that mega motor, what you really need to keep it in good health is a high-pressure/high-flow oil pump. Seems a sensible consideration - except in the A-series world it's impossible. Oh, there are pumps that will give better flow rates than others, but high pressure? Absolutely not.

Oil pressure is regulated by the relief valve in the block of an A-series, not in the oil pump as with say a Ford. Yeah, you know - the one that gets jammed, causing heart failure as you believe your crank bearings have dissolved, and is a pig to get out.

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