stock MCS crank pulley the same as stock MC pulley?

[mini_macky]

ey guys, heres my situation:

learned a while ago that my crank pulley is indeed wiggling which is causing premature wear to the alternator belt. i was just about to order a stock crank pulley from HK when a friend of mine said that he had an aftermarket pulley...but for a MCS. i already asked him if its stock in diamater (MCS-spec that is) i'm still waiting for his reply.but in anticipation...if it is stock in diameter...does it have the same diamater with the stock crank pulley of a MC? will it be a bolt-on piece to my MC? any input will be highly appreciated. i'm really at a loss when it comes to engines

[supercoopers]

I see no reason why it wouldn't work. The aftermarket pulley most likely does away with the dampener which is absent on the Cooper crank pulley anyway, so that's not a concern. I am not sure what the diameter difference is between the cooper S and cooper crank pulleys, but I would imagine they are the same given that the engines are pretty much the same structurally. If anything, it will be slightly larger in diameter to comensate for the fact that there is no supercharger pulley/tensioner to loop the drive belt around.

Best thing to do would be to accurately measure (with a vernier caliper) the diameter of both the stock cooper crank pulley and the aftermarket one your friend is offering. If they are the same then you are quids in. If they are different, then the effective drive ratio will change which will either speed up your accessories (AC etc) or slow them down, depending on whether the crank pulley is larger or smaller in diameter.

The bottom line is that, yes, the aftermarket crank pulley should work in theory and you can get a belt length to accommodate it's incorporation at worst, but there is no guarantee that you won't be damaging other accessories spinning off of the drive belt unless you check the respective diameters of stock vs aftermarket first.

If in doubt, just get a stock replacement crank pulley and you will have no worries then

Hope that helps.

Henry

[cristo]

actually, they're not the same

MC vibration damper (a.k.a. crank pulley) #11 237 829 906 weighs 1.360 kg
and the MCS viibration damper................#11 237 514 461 weighs 3.234 kg

according to my 2003 ETK

I assume they're the same diameter since they're driving the same alternator, but
don't know that for certain.

(hey, could you put an MC one on an MCS to save weight??)

[supercoopers]

The cooper doesn't have a 'vibration dampener' (rubber dampener) hence why it is so much lighter. BMW saw it fit to add a vibrational dampener to the Cooper S but not the Cooper due to resonances at roughly 1700rpm created by the addition of the supercharger.


You could in theory use a Cooper crank pulley on a MCS, but you would probably be better off getting an aluminium/steel crank pulley such as one from GT Tuning which will be both far lighter and probably better made (the tolerances on OEM crank pulleys aren't great. Just ask any MINI mechanic that has had to deal woth crank pulley replacements).

Cheers,

Henry

[Cooper_si]

Also use new bolt(s) when fitting the new crank pulley making sure the threadlock is applied (OE bolts normally have this applied already)

Ive seen a few work themselves loose because threadlock isnt applied and you dont want that now

[mini_macky]

thanks for the info guys

has anyone bothered to measure their stock crank pulley on their MC/MCS? post your measurements if you have guys! thanks