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CAM TIMING - Mechanical Method Part No Applications: MD256, MD266, MD276, MD286, MD286SP, MD296, MD296SP, MD310SP, MD530, MDM266/KIT, MDM276KIT, MDM286KIT Equipment required - Stop plate - mechanical stop plate for setting TDC (see text). Set of feeler blades Terminology - TDC - Top Dead Centre, when piston is at highest point in bore BTDC - Before Top Dead Centre, before piston reaches highest point in bore ATDC - After Top Dead Centre, after piston has reached highest point in bore Accurate piston position indication is the first goal. You need to know exactly when piston one is at TDC. Without engineering measuring equipment a ‘stop plate’ is required. This you will either have to manufacture personally, or get one made. You need a piece of metal plate long enough to span the bore plus a couple of the head stud holes on either side - about 4.750" long by 1.375" wide will do the trick.

Camshafts - Scatter cams, pros and cons

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.

Cylinder Head - Unleaded Fuel Use

The specter of 'unleaded fuel only' - instigated in UK on January 1st 1999 and seemingly from decades ago across the rest of the world - seems to be forcing more and more folk into frightened, panic orientated action. And Mini owners are featuring heavily in this. See bottom for useful part numbers. The situation not at all being helped by all sorts of conflicting information from 'leaned' sources, such as lead levels in humans has declined greatly since 1935 - despite the rapidly expanding ownership of petrol-burning vehicles. And benzene and toluene used in unleaded fuels are cancerous. Still, the powers that be are relentlessly forcing through the 'no heavy metals in fuel' bills, not being at all put off by such trivia. Not surprising bearing in mind the complete debacle on the catalytic converter front - the type decided on for world wide and universal use was developed and tested in California!

Cylinder Head - Unleaded Fuel Use

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.

Engine - Running in Procedure

This is another of those subjects that crops up on the message board frequently. I am constantly surprised by the number of engine builders - or people who charge other folk for building engines at any rate - that never hand out such an information sheet. It seems pretty daft to me that having taken a wad of money off of a customer for an engine you've lovingly put together, you'd want to help that person get the very best out of the engine. And the running/breaking in procedure is absolutely crucial. It at least ensures no damage is incurred when the engine first bursts into life. A collection of the usual suspects have explained their own methods on the board, along with various others - many of which probably work just as well for them, a few which are down-right dubious. Following is a sheet I administer with every customer engine I build.

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.

Cylinder Head - Unleaded fuel use

Cylinder Head - Unleaded fuel use

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 - Identification data

RUNNING IN NEW ENGINES

Install engine. It is absolutely imperative that the cooling system is more than sufficient to deal with any temperatures likely to be produced by the engine. More power means more heat to be dissipated. A standard radiator is very unlikely to be able to cope with a reasonable power increase over standard.

Do not fill cooling system yet. Set clutch throw-out and free-play take up. Double-check all connections electrical, oil, fuel and cooling system. Put in engine oil – use a cheap multi-grade mineral oil. DO NOT use either semi or full synthetic oils. They will stop the rings from bedding in. Remove spark plugs, and spin engine over in bursts of a few seconds to pick up oil pressure and prevent starter motor damage. DO NOT start engine until oil pressure picks up.

Once oil pressure is showing, check ignition timing statically. Set to figure advised by distributor maker, or if no figures available, set at around 6-8 degrees BTDC. Re-fit spark plugs a

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.

Establishing an accurate TDC reference point is of paramount importance when developing and monitoring ignition timing (and cam timing come to that). Terminology - TDC - Top Dead Centre BTDC - Before Top Dead Centre Establishing an accurate TDC reference point is of paramount importance when developing and monitoring ignition timing (and cam timing come to that). When an experienced engine builder assembles an engine - no matter whether for road or race - he will establish an accurate TDC indicator that can be used for ignition purposes. Usually contrived as a rigid pointer aligning to a corresponding mark on the crank pulley in a position easy to see with the engine installed. Unfortunately, many of us have to deal with engines that haven't had such attention to detail - so either have to make do with the standard ignition timing graduated scale if it's there or sort something else out.

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.

Lubrication - Temperature critical

The correct running temperature of the oil is perhaps even more important than the water/coolant temperatures - so let us consider how to control them.

Mainly because it seems to be the most misunderstood of the whole process, and oil cooler fitment almost a reflex when over-heating occurs where a tuned engine of any type is concerned. And in many cases on standard production road cars for that matter.

Almost since the appearance of the immortal Cooper S, fitting an oil cooler has been the essential thing to do to any tuned Mini without any comprehension why. The original fitment was necessary because oil and bearing technology wasn't too advanced. Asking an oil of yester-year to cope with lubricating an engine at racing speeds, and a gearbox pushed their performance to the edge of their all too narrow capability, so extreme control over their working environment was essential for reliability. Hence oil cooler fitment.

Performance orientated engines, particularly those utilising large over-bore sizes (i.e. 73.5mm), can suffer from premature head gasket failures because of the inadequate quality and performance from the standard head studs. Mini Spares has therefore produced a replacement kit to eliminate these problems.

The application of this drive system maintains very accurate and consistent cam and ignition timing, and minimising valve train noise. Desireable advantages that do not diminish with time. The fiberglass reinforced belt all but eliminates the excessive stretch suffered by chain driven systems - even where a tensioner is used.

Articles search results for Rocker cover

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