40 replies to this topic

[scrippo]

Hi all,

After looking all over the different forums I can't find an answer to my question.

I've discovered my dad has a spare BMW K1100 head (he actually has a spare for a bike for a change, not a mini!!) I'm currently 'in negotiation' to get this off him, so I can build an engine for my mini. I'm not yet sure if it's an 8v head or a 16v.

My questions are;

What parts do I need from the bike aside from the head?
Can I fit the head on any bore from the 1275 up (ie will 1293, 1310, 1340, 1380 bores work?)
I assume the head replaces the need for a cam in the A series block, is this correct?
I don't particularly want to munch gearboxes, realistically what spec of gearbox can I use? Will a rebuilt 'box with s/c gears and comp diff pin handle the power?

My plan would be to get all the machining/fabricating done by people who know what they are doing, then buy a kit from either MSPD or SC so I can bolt it together myself. I haven't got a massive budget, hence only going for this option if I can get the head cheap from my dad!

John

[Bungle]

there are a few topics about this in the projects section

i know scurvy dog is doing this conversion his self so start there

[Sam Walters]

it will fit any engine from 1275 up however the cam needs to stay in the block as it drives the oil pump iirc. some stright cut drop gears and a 4 pin diff should be okay, however keep below 140bhp with it and youll be okay, the clutch will need to be changed maybe a double grey.

stright cut drop gears are a must to be honest, however in the gearbox i belive stright cut gears to be just as strong as helical cut gears.

[scrippo]

Keep below 140 bhp! Like the sound of that!!!!! I think around the 110bhp mark will suit me fine. I had a 205 gti for a while that would be lucky to be running that and it was great fun, so a mini should be amazing with that sort of power!

Does anyone know what parts are essential off the bike?

[mini93]

could always get an electronic oil pump then u wouldnt need the cam in the block

oh and as for the kit JohnK at specilist components is the guy to talk to, if you buy the build guide for £20 tells exactly whats needs to be done! an absolutly exelent book

[Jammy]

An Orange should be fine for 110bhp, a grey for 150bhp+ really. Saying that clutches don't see bhp, they see torque...

You don't need straight cut gears for the conversion.

[scrippo]

Might go down the electric oil pump route. Can't see the point of keeping the cam in there if it's not doing anything other than pwer the oil pump.

Was thinking about buying that guide book, I think I'll wait until my dad actually gives in and lets me buy the head!!

The results from this conversion look pretty impressive. 107 bhp from an engine that is basically a standard block.

[mini_kel]

U will need to keep the cam in place unless u are running a dizzy less ignition system

[mini93]

most people do go for fuel injection so it seems sorry i seemed to take that for granted, mini kel is right yourl need electric fuel pump and distributorless ignition system. i think then you can also do away with the timing gear as well obviously it wont be driving anything

then go electronic water pump, electronic radiator fan, do away with the interior heater and get heated front screen

and last but not least a battery which will be able to cope, the redtop motorsport batterys i believe are high current for there size...ooh these are same as my plans lol

[scrippo]

Yeah I like the look of the Megajolt system with EDIS as it'll be much more reliable than the old points/dizzy combo, so that won't be a problem. Is it the fuel pump or the oil pump that I'll need to replace with electric (or both?).

Do I need to run fuel injection with that head?

[ginigwunkle]

itll be both as ther all driven by the cam!

you can use bike carbs, depends which bike it came off as to which bits will be included....

[mini93]

the k1100 was one of the 1st bikes to utlise fuel injection so if your planning to run carburettor a custom manifold will be needed

[matty...]

Has anyone got any links to these projects...cant' seem to find them anywhere?

Would be good to see how others are solving the endless problems they encouter..lol

[mini93]

matty, not really started anything yet, but mines linked in my siggy, got some help from ya lot over on turbo mini's

[matty...]

Ah looks like you've made a start. I see your blowing it too...good work!