A series engines with a Bike head

OK Gents (or Ladies)
I've seen 2 minis advertised for sale recently, and they claim to have 16v bike heads fitted ( I don't know which make ) - does anyone jknow anything about this ? Can you use the heads to their advantage when not using anywhere near the designed revs ? I suspect an A series bottom end would fly apart long before the bike bits reached the optimum speed, or are they just a trick bike engine ( Crank, barrells etc etc, just using the shell of an A series block to circumvent some or other rules ? Wasn't thinking of building one, just curious !

I have heard they are using a BMW K1100 16v bike head, slightly modified in order to fit the A-series block.......I think its the same engine used in the Formula BMW cars, which is basically the bike engine, which is a 4cyl laid on its side......google it and you will find more I'm sure

The K is not a screamer motor. In bike terms it is a good torquey unit. The motor is befitting of a BMW touring bike, strangely enough. Cams are mild. Advantages, well, 50% more valve area means more flow every where, regardless of optimum port sizes. Again, it is not like you are talking about a 180 hp donor motor. Yes the air may stall and provide a hole at less than say 2000 (for example) but the increased capacity will assist. I think the head will only go in an overbore... 1310... Can’t remember, it is 15 years since I have been in to mini's!

The conversion has been fully detailed in the specialist mini mags like miniworld. I am sure they have back issues available, and like knighty said, it will be on the web as well. That info didn't exist back in my day... I remember when I saw it in a Mag I was gobsmacked and impressed at the ingenuity of some one to do it using all production parts with minimal mods, like re drilling studs. (Against the KAD or Jack Knight heads that were specialist manufacture.)

If my poor old brain remembers correctly, I think that back in the late 60s early 70s there was the odd mini fitted with a cross flow head with fuel injection.

Driven in autocross by, I think, Roy Edwards.

Yes there were (8 valve) Arden (8 port) and Westlake (7 port) heads back then Mechanical FI, naturally. The 8 port is remanufactured by one of the specialists

Two other Minis that I remember racing in the 70s with ford engine conversions were a 2 cyl BDG?? powered mini and a Lotus powered one as well

Two other Minis that I remember racing in the 70s with ford engine conversions were a 2 cyl BDG?? powered mini and a Lotus powered one as well
I think the 2 cylinder BDA was raced by a guy called Peter Day. This car ended up written off and he built himself a Fiat 500 race car instead using the 850cc 2 cylinder BDA engine. CCC magazine did a feature on the car back in the day (it even made the front cover IIRC), quite a clever feat of engineering.
Also *back in the day* the 8 port crossflow Mini engines often used Amal (motorcycle) carbs with the bellmouths sticking out if the front of the bonnet. (The Vita- Min being one that I remember).
Must go now, got to get my pension before the Post Office closes...

The conversion is supplied as a kit from SC IIRC. It is expensive though!
http://www.scparts.co.uk/

Here you go, fron www.miniregister.com
I actually think it is a very cost effective conversion, heaps of potential for further Mods.


Specialist Components Cylinder Head
When it comes to tuning the A Series, the cylinder head comes in for its fair share of attention; if its chambers and ports are not being re-shaped and polished, the head as a whole is replaced.

A theme dating back to the sixties is to replace the 5 ports of the original with an 8 port cross-flow configuration. From the Weslake with its 4 Amal motorcycle carbs through to the more recent KAD and Jack Knight items with Alpha fuel injection they all benefit from improved gas flow and therefore more bhp. The cross-flow heads also benefit in that the camshaft (or rather camshafts) can be moved over the valves, which allows more liberties to be taken with the profile, by splitting the lobes of the single cam across the two cams, the angle of the valves can also be changed to beneficial effect. All this leads to significant performance improvements but it takes a lot of R & D, so when a ready-made head comes along that has benefited from the development budget of a large motor manufacturer, and by coincidence has the chambers in the correct place, it is not surprising that someone somewhere would graft it on to the A Series.



The head in question is from the BMW K Series motorbike engine and we first heard of a chap in Florida who had performed the surgery as a one-off, now Specialist Components in the UK have done all the hard work and are offering the conversion as either a kit of parts for you to source your own head or the complete service.

The K100, K1100 or K1200 heads can be used and these can be picked up for between £250 and £400, these come complete with camshafts, throttle bodies and fuel injection. To get the head to fit your block (1275) you will need the Specialist Components' conversion kit that includes:

1x Build Guide Book
1x Top Engine Conversion Kit
1x Bottom Cover and Seals
2x Alloy Vernier Top Pulleys
1x Lower Pulley Kit (Jackshaft and Crank)
1x Belt and Tensioner Kit
1x Copper Head Gasket (Thickness needs to be specified)
1x Block Drilling Template

Some machining work is required on the block with existing holes for waterways and head studs closed and new holes added as per the drilling template.

At this point the head and block are joined in a gas and water tight way and the camshafts will rotate as required, there remains, the fueling, sparks and exhaust to deal with.

Again Specialist Components have this covered, they recommend using the fuel injection that comes with the head along with a mappable ECU to co-ordinate fuel and spark - for which you will need a trigger wheel that they can supply. They can also supply a full flow stainless exhaust manifold to route the spent gasses away. The conversion kit costs £665, the exhaust manifold £250 and the trigger wheel £102.50 with another £80 for the ancillaries kit.

The K series heads come in both 8 and 16 valve form, if the converted engine is based on a standard 1275cc block you can expect at least 105+bhp from an 8v item and 120+ from the 16v. Obviously your motor will need a sufficiently strong and balanced bottom end to cope with the load.

If you don't fancy handling the conversion work yourselves, you can supply you own block and SC can do the rest for between £4500 for and 8V and £6000 for a 16V.

Specialist Components have used a clubman fronted estate as the development hack and the unit fits without any bodywork attention, as the head is taller and wider than the standard A Series unit, a bit of attention is required to the roundnose bonnet.

There is some footage of the conversion on YouTube at:

http://www.youtube.com/watch?v=974kBWoZfhs

http://www.youtube.com/watch?v=WBToBq6Oejo

Meanwhile, on the other side of the world...production is moving apace :)

http://www.ausmini.com/forums/viewtopic.php?t=37461&highlight=twinky

heres another one thats been done

http://www.miniman.com.au/bmw.htm

A quick search on www.16vminiclub.com throws up more info

heres another one thats been done

http://www.miniman.com.au/bmw.htm

A quick search on www.16vminiclub.com throws up more info

Sprinter....Mad Matt Read the Mini man from Brisbane QLD is the same fella I posted about :)