Bmw 16v K1200rs Head Conversion 1380cc Block

Well things have been progressing very well, here is the proof:-

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I have yet to bolt on the clutch side cover, the clutch and all the pulleys. This was just a quick assemble to get some pictures of last weekends progress.

Warren

Very nice engine, you're bloody brave putting it on a nice slate floor like that.

WOW!! Beautiful build. Where in Surrey are you?

Very nice engine, you're bloody brave putting it on a nice slate floor like that.

ssshhhhh!!!! Dont tell the parents.

Looking great....What have you done with the gearbox? Diff ratio...etc

Looking great....What have you done with the gearbox? Diff ratio...etc

Thanks, The gear set is the A+ 4 SYNCRO S/C ST RATIO with a 3.44:1 FD Crown Wheel & Pinion with MED 1:1 S/C transfer gears.

Should be a screamer!

WOW!! Beautiful build. Where in Surrey are you?

Wallington

Wow.!!! great build dude. Thats gonna run! The only problem is when you reach fourth gear, you'll wish you had a fifth. by the way. what viscosity oil are you gonna use? ans would it hamper the operation of the head or the gear box. A friend of mine had a toyota 4efe block and head on a mini gear box and boy was it scary! wheel spin on 1000rpm.! But the oil required by the engine was too thin for the gearbox so there was alot of gear noise. Hence the question.
very impressive build though.

Here's what it looks like in the engine bay. this was built by SC for me.


Everything is very tight.

how does the waterpump alternator belt turn over? looks like a standard (but shiney) waterpump pulley?

Edited by shed, 10 February 2011 - 09:17 PM.

Wow.!!! great build dude. Thats gonna run! The only problem is when you reach fourth gear, you'll wish you had a fifth. by the way. what viscosity oil are you gonna use? ans would it hamper the operation of the head or the gear box. A friend of mine had a toyota 4efe block and head on a mini gear box and boy was it scary! wheel spin on 1000rpm.! But the oil required by the engine was too thin for the gearbox so there was alot of gear noise. Hence the question.
very impressive build though.

Hi minidude1000,

I have put a lot of thought into the gearing for this engine. I did look into purchasing a 5 speed box but after reading lots of blogs, I decided that the 5 speed gearboxes available were not capable of handling the power that I was hoping of achieving. Plus replacement parts for certain manufacturers 5 speed boxes are difficult to source. I therefore decided to stick with the trusty 4 speed box and just replace the gears for SC ones to reduce the side loading effects of helical gears.

The design of the BMW K head with its aluminium cast body and dual overhead cam is capable of running at much higher RPM (up to 8500 RPM with SC cams) than the standard mini head. The choice of the final differential ratio was a bit of a compromise, as I wanted both acceleration and top end for economical use on the roads and power for the track. If I find that the 3.44FD crown wheel is not suitable, it is relatively simple to change this in the future.

I always run my pre 90’s minis on 20w/50 oil as specified in all the manuals. The correct choice of oil has been discussed plenty of times on this forum and everyone seems to have their own opinion. As the mini sump shares the same oil as the engine you must use oil that is not too thin like synthetic oils. These are too thin for the manufacturing tolerances used in the production of the engine components and the selection of materials used for making the oil seals. Otherwise you will eventually end up with lots of annoying oil leaks. The mini enthusiast nightmare! As 90% of the engine is original I will therefore be using 20w/50 in this engine and hopefully the head can cope with this thicker oil.

Hi all I managed to go backwards in progress this week. Pretty hacked off really.

I spent the weekend trying to complete the small bits and bobs left. One of these was trying to find a 1275 damper. Finally managed to find a good crank damper so I bead blasted it, primed and painted it. It looked like new. Then I decided to fit the damper to the crankshaft, it was a tight fit so i thought I would take it off and use some emery cloth to make it easier to fit. Problem was I couldnt get if off so i decided to use a puller. Guess what I should have just left it alone. Now I have broken my damper as i put the puller on the outside edge which decided to go bang. S**T! I should have just given up there but I decided that I would cut down the 4 cylinder head studs and fit them all with some locktite. All went well apart from one where the engineering shop has failed to tap the hole deep enough and i have ruined the starting thread on the stud. Iam also unable to get the sprocket that sits on the crank off the damper, any ideas how to seperate these anyone?

I feel like I have gone forward 5 steps and back 10. Damin it.

Warren

Hi everyone,

Finally I have made some real progress. Managed to get my hands on another crankshaft damper, this one is about 6mm thinner than the last one leaving more room between the trigger wheel and the damper. Spent this weekend preparing the replacement damper, first i bead blasted it followed by a coat of etch primer and finished off in matt black.

I have also managed to re-tap all the head stud holes, so the studs now wind all the way into the block. I added some medium threadloack compound to the studs prior to final install. Next was to place the head gasket into place followed by the head. The head nuts have been torqued down to 45lb/ft in progressive steps to prevent any damage to the studs or aluminium head.

I installed the camshafts to find the head nuts where clashing with the camshaft at the drive end. To fix this i had to undo all head nuts and add a small chamfer to 4 nuts. Finally I the nuts were re-torqued and the cams installled.


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coming along nicely

coming along nicely

Looking very nice!

Where did you get that crank damper from and is it 1275 or 998 one?