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C-AHT280 COMPETITION HEAD STUD, NUT & WASHER KIT

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.

CAM TIMING - Mechanical Method

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.

Brakes - How They Work

This time we’re going to look at just how brakes do what they do, and ways to improve them. Without a doubt the most important point to get sorted at the outset is just what makes brakes do their thing - FRICTION. The sole purpose of the brake set-up on any vehicle .....

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.

MSE6 - POST 1992 Unleaded Stag

Modified to give maximum performance gain for cost. Combustion chambers, inlet and exhaust ports extensively re-worked. Stone-ground finish in ports promotes ultimate fuel atomisation. Three-angle valve seats in head. Super-quality MG Metro valves modified to increase airflow. MSE6 - POST 1992 unleaded stage 2 (Road Rocket) large-bore head Part No Applications: MSE6, TAM1059, TAM1061, TAM2069, 12G1963, 12G1015, ADU4905 Inlet Valves: 35.6mm(1.401") dia. Original equipment type P/No. TAM1059 Exhaust Valves: 29.2mm(1.150") dia. Original equipment type P/No. TAM1061 Exhaust seats: Latest type Beryllium-based for lead-free fuel P/No. TAM2069 Valve Guides: AE Hepolite cast iron P/No. 12G1963 Valve Springs: Nominal 140lb. Max actual valve lift 0.400" P/No. 12G1015 Stem Seals : Latest 'top-hat' design with tensioner springs (inlets) P/No. ADU4905 Chamber Volume: Nominal 20cc Combustion chamber volume used to give slight static compression ratio increase over

MSE6 - POST 1992 Unleaded Stag

MSE4 - Post 1992

Modified to give maximum performance gain for cost. Combustion chambers, inlet and exhaust ports extensively re-worked. Stone-ground finish in ports promotes ultimate fuel atomisation. MSE4 - POST 1992 unleaded stage 2 (Road Rocket) large-bore head Part No Applications: MSE4, C-AEG544, C-AEG106, TAM2069, C-AJJ4037, C-AEA526, ADU4905 Inlet Valves: 35.6mm(1.401") dia. Tuftrided EN214N s/steel P/No. C-AEG544 Exhaust Valves: 29.5mm(1.161") dia. Tuftrided EN214N s/steel P/No. C-AEG106 Exhaust seats: Latest type Beryllium-based for lead-free fuel P/No. TAM2069 Valve Guides: Magnesium bronze P/No. C-AEA526 Valve Springs: Nominal 180lb. Max actually valve lift 0.500" P/No. C-AJJ4037 Stem Seals: Latest 'top-hat' design with tensioner springs (inlets) P/No. ADU4905 Chamber Volume: Nominal 20cc Three-angle valve seats in head. Cooper S size valves with current maximum flow profiles and Tuftrided for durability/longevity when used with unleaded fuel (hence 'black' finish).

MSE4 - Post 1992

Modified to give maximum performance gain for cost. Combustion chambers, inlet and exhaust ports extensively re-worked. Stone-ground finish in ports promotes ultimate fuel atomisation. MSE4 - POST 1992 unleaded stage 2 (Road Rocket) large-bore head Part No Applications: MSE4, C-AEG544, C-AEG106, TAM2069, C-AJJ4037, C-AEA526, ADU4905 Inlet Valves: 35.6mm(1.401") dia. Tuftrided EN214N s/steel P/No. C-AEG544 Exhaust Valves: 29.5mm(1.161") dia. Tuftrided EN214N s/steel P/No. C-AEG106 Exhaust seats: Latest type Beryllium-based for lead-free fuel P/No. TAM2069 Valve Guides: Magnesium bronze P/No. C-AEA526 Valve Springs: Nominal 180lb. Max actually valve lift 0.500" P/No. C-AJJ4037 Stem Seals: Latest 'top-hat' design with tensioner springs (inlets) P/No. ADU4905 Chamber Volume: Nominal 20cc Three-angle valve seats in head. Cooper S size valves with current maximum flow profiles and Tuftrided for durability/longevity when used with unleaded fuel (hence 'black' finish).

MSE3 -Pre 1992

Modified to give maximum performance gain for cost. Combustion chambers, inlet and exhaust ports extensively re-worked. Stone-ground finish in ports promotes ultimate fuel atomisation. MSE3 - PRE 1992 unleaded Stage 2 (Road Rocket) large-bore head Part No Applications: MSE3, C-AEG544, C-AEG106, TAM2069, C-AJJ4037, C-AEA526, ADU4905 Inlet Valves 35.6mm(1.401") dia. Tuftrided EN214N s/steel P/No. C-AEG544 Exhaust Valves 29.5mm(1.161") dia. Tuftrided EN214N s/steel P/No. C-AEG106 Exhaust seats Latest type Beryllium-based for lead-free fuel P/No. TAM2069 Valve Guides Magnesium bronze P/No. C-AJJ4037 Valve Springs Nominal 180lb. Max actually valve lift 0.500" P/No. C-AEA526 Stem Seals Latest 'top-hat' design with tensioner springs (inlets) P/No. ADU4905 Chamber Volume Nominal 20cc

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

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.

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.

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...

This is to help those floundering in an unknown sea of techno-babble and 'magical' cures… Part No Applications: C-AHT288, CAM150, CAM151, TAM1617, CAM4545, 51K1193, TAM1521, GEG300, C-AHT188, C-STR1057, A regular visitor to the message board, and something I am asked frequently about in my other incarnations for other technical media. Generally when something has gone badly wrong! Many folks have just as many ways of dealing with the following subjects - all can and will claim their way has worked for them for the proverbial millennia - so a few words as a basic reference and guide as I see them; we all know there are always exceptions to the rules. This is to help those floundering in an unknown sea of techno-babble and 'magical' cures…

Engine - Identification data

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.

Predominantly 13-inchers, but 12s as well, the main thrust of the questions being 'what do I need to do?'

This subject is a regular visitor to the message board and 'Knowledge' section of Mini Magazine for whom I write - fitting bigger wheels. Predominantly 13-inchers, but 12s as well, the main thrust of the questions being 'what do I need to do?' along with 'which wheel arch extensions will I need?' The answer has always been somewhat 'clipped' purely because of the space availability issues both in the magazine and on the message board, so something a little more detailed was required. Although the Mini suspension was designed around the use of 10-inch wheels with cross-ply tyres, a quick dash through history reveals that fitment of these bigger wheel sizes isn't a recent, 'modern' application.

C-AHT136 - TPi BUDGET UNLEADED STAGE 2

(ROAD ROCKET) LARGE-BORE HEAD.

Modified to give maximum performance gain for cost. Combustion chambers, inlet and exhaust ports extensively re-worked. Smoothed finish in ports - not mirror-finish polished to minimise drag. Multi-angle valve seats in head. Super-quality MG Metro valves modified to increase airflow. Combustion chamber volume used to give slight static compression ratio increase over standard. Head mods employed greatly increase volumetric efficiency, boosting actual running (dynamic) compression ratio.

Previous rocker spacer kits offered by various A-series specialists have largely contained just three spacers in various forms and materials. They all had one thing in common though – they were inadequate. The issues revolve around two basic problems – the varied position of rocker post and head studs through factory machining tolerance and the variety of widths of rockers arms.

Modified to give maximum performance gain for cost.

Exhaust seats Latest spec inserts for lead free fuel Modified to give maximum performance gain for cost. Combustion chambers, inlet and exhaust ports extensively reworked. Stone-ground finish in ports promotes ultimate fuel atomisation.

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