Has anyone fitted a smaller supercharger pulley to their r53 Cooper S?

My boyfriend has changed mine and now my car sounds awful both on idle or when driving. He is a mechanic so I'm assuming it's fitted correctly but he says the oil in the charger is low and that's why it's noisy.

Has anyone had this issue when they've tried this mod? I really can't live with the noise it currently makes so I'm praying that the oil will sort the noise out.

Oh and by the way he is forbidden to do anything else to it unless I give him permission or I'm going to sue him (I can do that? Right? ;-) )

you'd be better off asking the question in here..First Generation MINI Tuning - MINI Cooper Forum - MINI2 Mini Cooper Forums (http://www.mini2.com/forum/first-generation-mini-tuning/)

smaller belt is needed aswell,i've read some where

Fitting a pulley is a simple but specialised job. As I understand it you need a special tool to remove the old one or you can bend the shaft the pulley is on and the supercharger will be out of alignment and fuc#ed basically.

I have a 15% on mine and the only noise you should hear is lovely increased supercharger whine!

Hi ya opppps
Yes you can sue him :-) but you should make him suffer that's what women do Best :-) Just remember it better be a good valantines gift :-)

I think we need to know a few more things And we can help
1) Is it running rough or is it rattling like a pig is it low on power
2) what pulley did he fit what make and size did he use a shorted belt did he just do it or follow any instructions because if you are not carefull you can bugger things easy I have done quite a few now for people.
3) I would think if it was ok before changing the pulley it's not the oil there are two locations for the SC oil one is the snout (pulley end) and the other end under the water pump
4) did he do the job by jacking the engine up and using a puller to remove the pulley
Let us know then we can help :-)


Ps be kind to him he was only trying to help :-)

He has just informed me that he used the correct puller.
He also states that if the SC shaft was to bend it would give a vibration on idle and at high rpm.

There is no power loss or hesitation throughout the rev range.

The noise goes with the engine rpm as if it's an internal metallic sound.

He used 17% pulley from johnspeed4minis.

Hi ya
Just looked at john speed pulleys if It's the one I found its a shrink fit ie heat up in the oven and press on and leave to cool or cool of with water.
It may be on to far and rubbing against the SC housing I am not shore with this one if it has a stop in side it to stop it going in to far.
But you have to be carefull to make shore the belt is in line or at hi revs and a little while down the road it will kill the belt and spit it off.
Did the pulley go straight on or did he have to tap it with a mallet

Most of the pulleys i do are two piece pulley normaly alta always been very good
Never had a problem
Has you car got any other mods to it

Hi it's stu here (Boy friend)
The pulley was heated up and was slid on with a little tap to send it home. ( I used a dead blow hammer to minimise any damage)
The pulley is inline with the tensioner so the belt is sat correct and flat.
The SC could be turned by hand after the pulley was fitted with little resistance.
If damage has been caused by me knocking the pulley on I will replace the SC unit and have Rachel's overhauled.
It makes sense that if the pulley is on too far it will foul the housing/ thread the belt.

Hi stu

I think may be it worth taking the belt off and seeing how free the pulley is now.
The SC should be smooth And fairly free to turn by hand with no backlash if you rock the pulley back and forth it
It may be possible that buy tapping the pulley the shaft may have moved in wards and the pulley is rubbing on the casting you need to see if you can get a enderscope or bit of paper around the back of it see if there is a gap you don't need to move them much I have seen it done. The one I saw the pulely was rubbing on the part of the casing where the input shaft seal fits
I have had a few SC's apart if this is the case you could take out the SC and remove the snout housing of the SC body and press it back.
To get them overhauled in uk I have not found anyone who is intersted I have places to get bearings seals and gears ect and recoating for the rotors I can PM you if you need it If you get stuck
But if it was me I think I would make shore the pulley puller fits well to the smaller pulley and may be just give it a little tweak to pull the pulley back off you might only need .010" just to clear the SC case
While the belt is off make shore the tensioner pulley is ok just Incase it's given up the ghost At the wrong time you know sods law and all that's


Sorry to asks but has anyone advised you about change the intercooler, spark plugs, tensioner stop post pulley change sorry to ask

Check that the tensioner is actually tensioning the belt correctly.

There should be at least 1 hole visible, similar to what is in the picture (this tenioner is compressed for belt removal)

There is also a damper on the tensioner assembly, make sure this isn't broken either

Plugs are those from a works in NGK.
Tensioner has one hole showing and a little bit more.
Tensioner damper has seen better days no bounce back looks like its leaked. Needs replacing (like a knackered boot strut.)
Looking at either gtt or Gp cooler with air devider

Ill recheck the pulley and bring it forward 1tho and start it up.

If I have moved the shaft inwards I'll remove the cone and repress it in to position.

Never stripped a SC before so I could do with a work shop diagram with measurements and torque settings.
PM me the deeds for the bearings etc as I know the water pump teeth can wear.

This is the 1st SC car we've had, I've ran high powered turbos in the past (jap)

Hi ya

Will try to dig out some bits for you
I don't have any manuals or the SC as eaton don't give them out I just marked and engraved everything as I stripped it the most important bit is the rotor timing but like I say match mark everything can't go wrong.
I used standard bolt TQ settings for all the bolts and used Honda bond in the casing faces for a proper seal
I will PM you the links tomorrow
I have a gp intercooler works well you need a few extra bits if You are going to fit it have a list somewhere.
or the only other option for me is a GRS intercooler Motorsport version I think there about the best money can buy.
Sark plugs a lot of guy use iridium ones I use NGK BKR7EIX
The damper only damps no spring back I fell in to the Same trap
Also get your self a tensioner stop from alta or gt tuning if the belt fails it causes a mess

I've seen the belt stops.
Looks like 2, 8mm electrical terminals crimped on to steel cable.
Very wise idea.
I'll knock one up when I'm back to work.
8x10 I use 8mm cable should do the job and 10mm for the bolts. :-)
The the pulley puller is to big I'll use my leg style puller and see how it goes.
Rach is guttered and so am I!
Took me around the 3hr mark so it's gonna be another good 2 hrs. I'll crack back on it tomorrow and let you know what's what.

No problem mate
unfortunately these things happen it just life.
See how it all unfolds tomorrow fresh eyes and all that
Someone here might pop up over night and come up with something

Stu here.

Stripped it alll back down today and rechecked belt idler, tensioner and charger.

The charger felt rough and tight (even after moving pulley 010tho) i checked it over and the main noise was from the nose cone bearings.
Ive ordered the folowing

Super charger unit 5000 miles

Full bearing and seal kit from usa

Two bottles of charger oil.

New Water pump (might aswell change as im in that area)

I am going to fit the new charger with 17% pulley when it arrives and i will rebuild the charger that is removed with new parts.

2 weeks after fitting a smaller pulley the blower
began screaming. Managed to get a replacement
under my extended warranty. The bearings went bad.
Coincidence?

Early MCS had a problem with the super charger gearbox running out of oil. When this happened they got noisy due to the gears running dry and wearing out. There was no fix except to remove the charger, open the gear case and add oil, IF the damage was not too bad. It is a LOT of labor to get to the supercharger.

When changing the Super Charger Pulley, the old pulley should never be pried off.
If the old pulley is not removed with an appropriate puller, and the a new collet type pulley slipped on in alignment, then the water pump drive gear on the back of the charger may shift on the shaft and contact the case.

It is also possible to have the collet type pulley move while installing it. This will cause the belt to run out of line and probably rub on something. This is easy to fix by adjusting the pulley.

If the pulley was smaller than 15%, then a smaller belt must be used or else the tension pulley will rub on things and make a pretty nasty noise until it fails.