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MODIFIED IN HOUSE FOR OVER 35 YEARS….

All of our cylinder heads are proudly machined in-house by our experienced engineers. Years of design and development work has given us a wealth of knowledge, so we can supply you with an unbeatable product.

INLET PORT MODIFICATION 
HEAD REFACING
CUSTOM CHAMBER SHAPES

OUR EXPERTISE

We have been modifying A-Series cylinder heads for over 35 years, supplying thousands to satisfied road and race customers worldwide. In addition, we also supply heads to numerous other leading engine builders and teams.

Our experienced engineers handle each machining process in-house. This gives total control over the quality, allowing us to supply the finest cylinder heads available for the 1275cc A-Series. Famous worldwide for quality and performance, MED heads really are the best you can get!

When browsing the range, you’ll notice that MED cylinder heads are not categorised into numbered stages. Instead we machine heads for specific applications, each then customised to perfectly suit your engine build.

Remember that most engine specialists work to similar hourly labour rates; if the price on a modified head seems to good to be true, it’s likely that corners have been cut on component quality or machining time.

INITIAL INSPECTION

For race cylinder heads we insist on modifying castings without valve seat inserts fitted, as they have a tendency to work loose, often with catastrophic results. Castings with valve seat inserts are still suitable for MED Road Competition and Turbo heads that utilise the smaller size valves, however.

Firstly we take a standard 12G940 cylinder head casting and perform a thorough inspection to check the overall quality and suitability. We usually ask customers to mark and supply their own casting as a basis, although we do keep limited stocks for outright sale.

We check for general damage, stripped threads and cracks or imperfections within the chambers and ports. It’s also important to measure the deck thickness, as castings with thin faces are not usually suitable for a race head. We skim more material from race heads to reduce the chamber volume, leading to problems around the water jacket holes.

MODIFICATION

For large valve offset race heads we initially machine the exhaust valve guide bores oversize to fit offset sleeves. This allows the use of our motorsport-grade bronze guides to be fitted in an offset position, enabling an extra large inlet valve head within the combustion chamber. With this technique we can install up to 38mm inlet valves beside 31mm exhausts.

Mounted on our cylinder head machining centre, the valve seats are cut with special three-angle valve seats to within 0.001-inch tolerance. For all race heads we also enlarge the pushrod bores and install sleeves. The sleeves then act as a guide during port modification, highlighting when we have reached the maximum possible width of the inlets.

Now the hard work begins, with inlet and exhaust ports fully modified to our flow bench and dyno-proven profiles. Once this painstaking procedure is complete, we then install new valve guides, drill the cylinder head for 11-stud fixings and re-face the rocker cover face.

An important technique often neglected on budget cylinder heads is to then machine the valve spring seat seats to gain an equal height for the fitted valve springs.

The final manual machining now takes place within the combustion chambers, which are balanced to within 0.2cc. The combustion chambers are filled with the desired volume in fluid, depth checked to the head face and then skimmed on our CNC milling machine to give the correct volume.

The cylinder head is assembled with a set of our race-proven 21NS plasma-nitrided valves, double valve springs, new valve retainers and CNC-machined collets. Road Competition heads can re-use the standard triple-groove collets and top caps.

SPECIFICATION AND PRICING

From modified road to full race cylinder heads, we have a bespoke product to achieve your goals. All MED heads are machined by hand in-house by our skilled engineers.

MED ROAD COMPETITION

£950.00 (inc VAT based on exchange)

*Please add £200 if no suitable head to exchange.

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MED FORCED INDUCTION

£1000.00 (inc VAT based on exchange)

*Please add £200 if no suitable head to exchange.

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MED RALLY SPECIAL

£1,050.00 (inc VAT based on exchange)

*Please add £200 if no suitable head to exchange.

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MED CLUBMAN- RACE

£1,400.00 (inc VAT based on exchange)

*Please add £250 if no suitable head to exchange.

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MED CLUBMAN- OFFSET RACE

£1,500.00 (inc VAT based on exchange)

*Please add £250 if no suitable head to exchange.

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MED SERIES 6 - RACE

£1,950.00 (inc VAT based on exchange)

*Please add £250 if no suitable head to exchange.

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A very popular choice! This cylinder head comes finished with 36mm inlet valves and 30mm exhaust valves, carefully ported to suit fast road and light competition cars with single or twin SU carburettors. It is supplied with unleaded exhaust valve seat inserts.

Valves are manufactured from 21NS stainless steel forgings, plasma nitrided for extra strength and wear characteristics, and the valves run in our own high quality bronze valve guides. The combustion chambers are expertly re-profiled and the capacity optimised to gain the correct compression ratio for the specific engine.

Final assembly is completed with MED road-spec double valve springs, triple groove collets and valve retainers. These cylinder heads can be drilled for 11-stud head fixings and painted in a variety of colours, ready to fit.

For those with a love of boost! A variation on the MED Rally Special, with larger chambers, 35.7mm inlet valves and 30mm exhaust valves in a single-groove design. It is supplied with unleaded exhaust valve seat inserts.

Plasma-nitrided valves run in our own high quality bronze valve guides, while the combustion chambers are professionally re-profiled and enlarged to reduce the compression ratio and improve flow. Typically we can go as large as 28-29cc on the chambers.

Final assembly is completed with MED road-spec double valve springs, single groove steel collets and steel top caps. These cylinder heads can be drilled for 11-stud head fixings and painted in a variety of colours, ready to produce high power outputs.

The one for rally heroes! This cylinder head comes finished with 35.7mm inlet and 30mm exhaust valves manufactured from 21NS stainless steel forgings. This specification comes with single-groove valves in our high quality bronze valve guides, like a full-race head. It is supplied with unleaded exhaust valve seat inserts.

Both inlet and exhaust ports are modified to a large-port design, to suit a Weber 45 DCOE and large bore exhaust manifold. The combustion chambers are re-profiled to exacting standards and finished off to gain the perfect compression ratio for the engine.

Final assembly is completed with a choice of MED road or race-specification double valve springs, depending on the application. There’s also MED single groove steel collets and steel top caps. These cylinder heads can be drilled for 11-stud head fixings and painted in a variety of colours.

Flow bench designed and tested for maximum airflow on our Superflow 110 flowbench, this head uses the very latest development in port design with high roof inlet ports and negative radius valve guide boss removal.

The combustion chamber is modified with full radius side walls and double radius valve seats, which are all cut to race tolerances. This helps maintain equal combustion chamber volume and equal valve spring fitted lengths.

The valve seats are blended into both chamber and port to maximise airflow. This specification now comes with a 30mm exhaust valves and a 37mm inlets. The head comes fully assembled with race valves springs, steel valve caps and new single groove collets. Painted, fully machined and ready to fit.

For racers who need even more power! Flow bench designed and tested as per our Clubman specification for maximum airflow on our Superflow 110 flowbench. This head uses the very latest development in port design with high roof inlet ports and negative radius valve guide boss removal.

The significant difference with this specification is that we offset the centre line of the exhaust valve, which in-turn enables us to fit larger exhaust valves. This specification now comes with 31mm exhaust valves and 37mm inlets.

The combustion chamber is modified with full radius side walls and double radius valve seats, all cut to race tolerances to help maintain equal combustion chamber volume. The valve seats are blended into both chamber and port to maximise airflow.

Valves are race quality 21ns steel plasma nitrided with wasted stems and three-angle valve seats. Before our own high-flow bronze valve guides are fitted, the valve spring platforms are machined to maintain equal fitted length of the valve springs. The head comes fully assembled with race valves springs, steel valve caps and new single groove collets. Painted, fully machined and ready to fit.

The ultimate five-port race head! Our famous 38/31mm Series 6 full race cylinder head with 6mm stem valves. We have been producing this specification for many years now with great success. It is used in all forms of motorsport around the world and gives unbeatable power when fitted to the correct engine configuration.

Flow bench designed and tested for maximum airflow on our Superflow 110 flowbench, this head uses the very latest development in port design with high roof inlet ports and negative radius valve guide boss removal.

The combustion chamber is modified with full radius side walls and double radius valve seats, all cut to race tolerances to help maintain equal combustion chamber volume. The valve seats are blended into both chamber and port to maximise airflow.

The head comes with 31mm exhaust valves with offset centre line positioning, enabling us to fit extra large 38mm inlet valves. These give the extra airflow required for large-capacity race engines.

The valves are our own bespoke design produced from a one-piece plasma nitride forging with a lightweight 6mm stem and three-angle valve seat, probably the best valve available for the A-Series engine.

Before our own 6mm high-flow bronze valve guides are fitted, the valve spring platforms are machined to maintain equal fitted length valve springs.

Finally the head is carefully assembled with our lightweight titanium valve caps, dual rate valve springs and bespoke 6mm collets. Supplied with the cylinder head are our button lash caps, which locate inside the titanium cap for the roller rockers to run upon, giving a greater wipe area for high-lift camshaft applications.

MED FIA APP K – CUSTOM

£2,100.00 (inc VAT based on exchange)

*Please add £250 if no suitable head to exchange.

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MED SE7EN

£2,100.00 (inc VAT based on exchange)

*Please add £250 if no suitable head to exchange.

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MED MIGLIA

£2,100.00 (inc VAT based on exchange)

*Please add £250 if no suitable head to exchange.

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Machined to our own unique design, this specification has been used by many other engine builders and competitors in the historic racing scene for many years now.

As this cylinder head’s finer details need to be customised to the individual engine, please contact us for more in-depth information.

Our involvement in the Mini Se7en series stems way back to the 1980s, when we first started to produce many leading ‘Works’ engines. Cylinder head design has developed immensely over the years, changing with both time and the regulations.

Port and combustion chamber profiles are regularly examined to keep our heads at the front of the pack, in both Mini Se7en and Miglia championships.

As this cylinder head’s finer details need to be customised to the individual engine, please contact us for more in-depth information.

Our involvement in the Mini Miglia series stems way back to the 1980s, when we first started to produce many leading ‘Works’ engines. Cylinder head design has developed immensely over the years, changing with both time and the regulations.

Port and combustion chamber profiles are regularly examined to keep our heads at the front of the pack, in both Mini Se7en and Miglia championships.

As this cylinder head’s finer details need to be customised to the individual engine, please contact us for more in-depth information.

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