MED MULTI-WEB CRANKSHAFT KIT - MINI
Technical Video:
Description
The MED Multi-web crankshaft features an almost perfect 50/50 balance factor, which in conjunction with the exclusive six-inch non-offset conrod, eliminates rotational twisting and piston side loadings normally associated with the standard A-Series configuration.
With this crankshaft package, the engine will achieve a higher rpm and in turn maintain a higher bhp for longer.
The crankshaft is only supplied with conrods, as these are a unique design that features a narrow width, large diameter big end journal size for weight reduction and strength.
Crankshaft kit main features;
- Engine configurations from 1293cc to 1460cc
- Eight full knife-edged counterbalance webs
- Two extra 'ghost' main bearings for greater strength
- Narrow width, large diameter and hollow-drilled big end journals
- Extra long square-section key way
- C-clip groove deleted for extra nose rigidity
- Steel non-offset H-section 6.000" conrods
- 18mm bushed conrod little end journals
- ARP conrod fixings
- Omega forged lightweight, short-height pistons
- ACL bearings and thrusts
Each crankshaft is supplied with a set of Omega forged lightweight short-height pistons to complete the competition-grade package. These are available in a number of different configurations, so a member of our sales team will contact you after purchase to confirm.
A set of ACL Race main and big end bearings are included alongside ACL thrust washers.
Finally there's a special bronze bush to replace the primary gear C-clip, which will need to be machined down to achieve the perfect end float.
Please note - the timing gear end has a carefully machined radius for extra strength - please be sure that your timing gear sprocket has a matching radius or damage will be caused on assembly.
Frequently Asked Questions
Why is an MED multi-web steel crankshaft the ultimate setup?
The counterbalance effect is especially impressive with the multiweb, even more so than the popular EN40B steel crankshaft. An improved counterbalance effect helps to reduce the 'whip' often encountered with the three main bearing A-Series crankshaft, to much improve longevity and performance at higher RPM levels. This unique design utilises a narrower yet larger diameter big end journal size for extra strength along the crankshaft. There's also a unique design of non-offset conrods to reduce the effects of excess piston side loadings.
Is this a standard replacement?
Yes and no - it will fit a standard 1275 block but the gearbox housing may require minor modification for clearance. We would also highly recommend a steel main cap upgrade, which will then require line-boring. The narrower big end journals mean that standard type conrods do not fit; therefore we can only supply the crankshaft as a complete package with conrods and pistons.
Do I need to use steel main caps?
Ideally, yes. We would highly recommend an MED four-bolt steel main cap set, 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 such a high-end crankshaft.
Are different stroke lengths available?
Yes we keep both a standard 81.33mm stroke or 86mm stroke version. We only supply the 86mm long-stroke crankshaft when creating a 1460cc engine (essentially a long-stroke 1380), as this will require super short height pistons that are only available in the 73.5mm size.
Which pistons do I need?
The bore size may depend on your race regulations, the block you have to work with, or personal preference. We can supply a range of different bore sizes and crown designs to create your desired compression ratio and capacity. When opting for 1460cc, we supply an 86mm stroke crankshaft and super short 1.115" compression height pistons. For all other combinations we supply 1.248" height pistons.
Can I use this kit in a road engine?
Most of these crankshaft kits end up in competition cars, but we have also supplied many to builders of potent fast road cars. They make a particularly strong and smooth-running fast road engine where the budget allows.
How do I set the primary gear end float if there is no C-clip groove?
We have found over the years on powerful A-Series engines that the C-clip groove can be a potential fracture point, so on the Multi-web kit this is omitted from the design. Before final assembly of the engine, mount and torque up your flywheel on the crankshaft taper, with only the supplied bronze bush fitted in between. Ensure the bush is pushed up against the inside edge of the flywheel, and now measure the distance between the rear of this bush and the thrust face of the crankshaft. From this measurement, subtract the thickness of your primary gear and thrust washer and machine the difference from the bronze bush to achieve the desired 0.010" end float. Contact us for further help if you're unsure.
Can I buy just the crankshaft and use my own conrods/pistons?
Only if you already have a set of MED Multiweb-specific conrods, as these run a unique big end journal design to create a non-offset assembly. Regular steel or Cooper S conrods will not fit the crankshaft. Likewise with the pistons, you will need to ensure these are the correct compression height and gudgeon pin diameter to suit - 1.248" and 18mm for 1293-1380 kits. The 1460 kit runs a special 1.115" compression height piston set.
I'm unsure which combination of pistons, conrods and crankshaft I need - can you help?Can I use this kit in a road engine?
Yes, please contact us via email or phone and we'll be happy to help further. Simply let us know what compression ratio you are aiming for, or if you're not certain, the general engine spec and usage. We can put together many different combinations to best suit your engine build plans.
Where are MED crankshafts and conrods made?
Our crankshafts and conrods are manufactured just 20 minutes from MED at Arrow Precision Engineering - the very best in the business! We've worked with Arrow for over 20 years to create the best possible product.