A friend of a friend has recently binned the sickly, original 875cc engine in his Hillman Imp in favour of a BMW K1200RS bike engine.
BMW K1200RS Engine often features in a Grinnall Scorpion. It’ll fit nicely into a Hillman Imp or one of its derivatives …
Apparently, it’s well-known transplant. Who knew? I didn’t. However, I do now. I had to pop round his house and have a look. It’s a fiendish thing and the little car goes even better as a result. Sure, the Imp is a lot heavier than the BMW K1200, plus its engine weighs about 75kg rather than the Imp engine at 60kg.
Mind you, his Imp had about 40bhp, whereas the K1200 produces around 130bhp. It also sounds glorious.
There’s some kitcars running around using an old Imp unit that by now may have become a little bit asthmatic that might benefit from such a transplant. The BMW K1200 isn’t a stranger to kitcar use after all.
Mark Grinnall uses them in his brilliant Scorpion III three-wheeler and has done for many years.
… or it will also fit nicely into a Imp-engined kitcar like this lovely Davrian
My mate says that you can find K1200 engines on eBay from around 400 quid although he used the services of a West Yorkshire-based company called Motorworks and he bought a used engine as part of a kit package for just £795 inc VAT and this included engine, throttle bodies, injectors, airbox and all its gubbins, wiring loom and exhaust headers. More from www.motorworks.co.uk.
He reckoned that the trickiest part of the whole process was the gearbox. Some suggest using the standard Imp gearbox, although with the extra power and grunt that can struggle a bit. If you had an open budget a Quaife six-speed would be very nice. In the end my friend went for a bellhousing conversion.
Other BMW bike engines can be used such as the K1100LT unit only that only has about 100bhp but it will be cheaper to buy I would think.
The K1200 bike was produced between 1997-2005 and they produced about 38,000 of them. The engine is all-alloy, water-cooled, DOHC with 16-valves. Although it runs in the opposite direction to the Imp’s Coventry Climax-inspired engine it does have a contra-rotating flywheel, which rotates in the same direction as the Imp unit.
If you search something like ‘BMW K1200 into Hillman Imp’ or similar Dr Google should give you some pointers.