[mike1967]

I am replacing the timing chain on a 2010 N12 Cooper (non-turbo).

Once I have fitted the new sprockets, chain and guide rails, do I need to pre-tension the chain or do I just fit the new plunger tensioner? In the cam locking kit, there is something with threaded barrel and a threaded bolt through it: it looks like it would thread into the hole where the tensioner goes. Do I use this in some way?

I hope that I have everything in the right place before I take out the old chain. I have the flywheel pin pushed in fully, four sticks on top of the pistons are all level, the writing on the camshafts is on the top and the cams are locked.

Regards,

Jamie

yep you have got it locked correctly,, YOU MUST HAVE A 27MM NARROW OPEN END SPANNER sorry fo cap's on its so important when you tighten camshafts bolts you must hold the camshaft with spanner and not use the lock tool on cams to prevent cams turning,, if you do you will stretch the lock tolls and the cams will move out of time,,,
remove the dip stick otherwise cant get rail guides out, the screw in tensioner tool is a preload tool while you set chanin up, ie all sprockets free wheeling then preload with that tool to mimic the force the tension would give to it,, i use finger force only to avoid over tightening,, i watch the chain start to go tight and guess where the book says 0.4nm good luck finding a torque wrench for that,, this is important part, once done i set the cam bolts to 20nm each and crank bolt to 40nm, then remove the preload tool insert the tensioner rotate engine and relock the engine. must rotate clockwise never the other way at any point, then reinsert pretensioner check all locks drop on the cams and pin is easy in then its timed correctly, remember its best to be fussy at this point get it right it should all lock with no force if dont release cams and re preload and try a again,, once timed 20nm on cams then i do plus 90 plus 90 on each cam,, some do it plus 180 but 90 gives the bolts chance to recover a tad and crankshaft bolt leave pin in 40nm plu 100 or as tight as a 6ft bar will go

 

[mike1967]

Mike,

Thank you for your detailed reply, which is really helpful. I have just ordered a 27mm spanner and shall be ordering the chain kit tomorrow. Fingers crossed that I get it all back together again properly and that it works properly.

Regards,

James.

if you have any doubts at any point no question is a silly one, it dont cost you anything to ask,, its costs a lot when dont and find it damages something,, always check and check again always turn engine by hand before tightening the bolts all the way

 

[mike1967]

I have finally finished replacing the timing chain and tensioner. It took a while due to delays in getting parts delivered. However, it is all back together and working perfectly.

Thank you for your help and guidance on here, without which I should have struggled.

Regards,

JamieA

ideal bud glad it worked out ok its one of those jobs that they have made over complicated and open to all kinds of get it wrong moments, i've lost count the amount of done but the very first ones many years ago were trial and error as bmw would not release much info on the prince engine when it was just over 3 years old, like anything its just a process and easier to learn from others mistakes i find, glad to of helped