MED EN40B CRANKSHAFT KIT - INLINE
( £2,833.33 EXC VAT )
The MED crankshaft is CNC machined from steel EN40B billet and nitride hardened, with extra large C-shape counterbalance webs to reduce potentially damaging harmonics. There's an extra long keyway for a more positive crankshaft pulley location. Big end journals with counter-bored webs reduce weight and further enhance the counterbalance effect.
The fourth photo shows the counter-bored drilling for the big ends, a process that reduces the reciprocating weight of the crankshaft and does not necessitate drilling through the counterbalance webs.
As used in all of our inline race engines, from five-port to eight-port and 16-valve. With hundreds of crankshafts sold worldwide over the past decade, this remains the best priced EN40B steel billet crankshaft available for the 1275 engine.
Available in 68.26mm, 81.33mm or 86mm stroke, with a C-slot for the standard primary gear setup. Crankshafts without the C-slot are available on special request.
Where the shaft on the timing gear end of the crankshaft meets the main journal, there's a radius machined in for extra strength - please be sure that your timing gear sprocket has a suitable radius for clearance.
We also offer a complete crankshaft kit package with a choice of pistons and MED steel conrods.
See the Extra info tab for frequently asked questions.
Why is an MED steel crankshaft better than a standard type?
Most factory crankshafts were forged from lesser grade EN16T, as opposed to CNC-machined from EN40B steel billet. The counterbalance effect is also far greater with this design. Whilst forged crankshafts can be very effectively re-worked to improve their counterbalance effect, it is not possible to add material, only subtract.
An improved counterbalance effect helps to reduce the 'whip' often encountered with the three main bearing A-Series crankshaft, to improve longevity and performance at higher RPM levels. Starting with a brand new crankshaft also has a reliability advantage over re-working a second-hand crankshaft of unknown history.
Do they come with any certification?
The crankshafts are supplied fully balanced with certification, 100% crack detection and certification of material and heat treatments. Critical detail inspection reports are also supplied with the crankshafts.
Does this weigh less than a standard crank?
Yes - approximately 1kg less. Once re-worked, a standard crankshaft could potentially weigh less, however the intention is not to save weight, but improve strength and counterbalance.
Do I need to convert the block for a steel main cap set?
Ideally, yes. We would highly recommend an MED four-bolt steel main cap set with rear oil seal conversion, AFS studs and line-boring of the block when upgrading to a steel crankshaft. On a road car, an MED centre main strap kit may suffice, but it's not the ideal arrangement when using a high-end crankshaft.
Which conrods and bearings do I need?
The big end journals are sized at 1.625" as per the standard 1275 Sprite, so original conrods will fit. However we would highly recommend upgrading to a set of MED steel conrods for extra strength and reduced weight. Main bearings are standard 1275 A-plus size, big ends are standard as above and thrusts are standard 1275 type. To make things simple we can supply a complete crankshaft kit with everything you may need.
Is this a standard replacement?
Yes - aside from the recommended steel main cap upgrade, this is a direct replacement for the standard-type crankshaft and does not require any additional machining of the block or gearbox, in all strokes.
Can you make me a steel crankshaft for my Ford Focus/Honda Civic/Subaru Impreza?
We specialise exclusively in the BMC A-Series engine and focus primarily on racing Minis and Spridgets. Currently we have no plans to design crankshafts for other vehicles/engines.