Mmg Underdrive Pulley Kit - Turbo Only

Remove the remaining bolts retaining the brackets

Using a suitable socket and bar, pull the tensioner pulley back to allow removal of the belt



Undo the crank pulley small bolts (4 of), not the central one! You may need to lightly tap it with a small hammer to release it (mine had recently been removed for a cambelt change)



Comparing the old and new pulleys:

Removing the redundant pulley and tensioner pulley - these were hard (but possible) to get to from just the wheelarch access, but very difficult to get the camera in! Firstly undo the three bolts holding on the idler pulley



I could not release the tensioner pulley unit from the casting it is bolted to, but fortunately it has all got to come off anyway

And then this is what you should end up with post removal - you can see where the mounting holes and bolts go...



Now offer up the new crank pulley up and line up the holes with the crankshaft - note that the pulley will only fit in one position with all the holes lining up. Also a smear of copper grease on the mating faces helps assembly. Re-use the old bolts, adding a small amount of thread lock to prevent them becoming loose


Fit the belt that comes with the kit - you will need to loosen the lower alternator mounting bolt (it screws into a 17mm nut underneath the alternator)


Note the safe distance between the oil pipe unions and the new pulley and belt


Fix the alternator adjustment bracket to the cylinder head, and attach the top alternator bolt using the supplied washer, and adjust belt tension to give around 1/2" of flex between the two pulleys. Tighten the top alternator bolt when desired belt tension is achieved. tighten back up the alternator lower mounting bolt...


Check all torques with the relevent section in the TIS, refit the wheelarch liner, and then the wheel

Compiled Fitting guidleines (in pdf format) now on Wiki site
>>here<<

Not meaning to upset anyone, but I mentioned these to an engine developer today and they seemed to think they were a really bad idea - especially on an engine that doesn't run a dual mass flywheel

Not meaning to upset anyone, but I mentioned these to an engine developer today and they seemed to think they were a really bad idea - especially on an engine that doesn't run a dual mass flywheel

Did they explain the reason why it's a bad idea ???

Did they explain the reason why it's a bad idea ???

Only in that the weight distribution of the OEM pulley will be precisely calculated to work in conjunction with the flywheel, and balance the crank; changing this balance could dramatically reduce the overall reliability of the crank. The OEM pulley could also be cored to provide additional damping ()

(he did give a proper explanation to be fair [including moment of inertia derivation], but had to translate into the lamens terms above so I'd vaguely understand in the few minutes we were talking about it)

Does that mean lightweight flywheels are a bad idea too?

Does that mean lightweight flywheels are a bad idea too?

Yep, apparently so (and lets face it, a lighter flywheel would be cheaper to manufacture, so I'm sure they would have done so)

Although I should point out that the tuning stance this guy takes is always to place reliability before horsepower (which I like ) I fully trust his opinion, but it is just that, an opinion


Of course if you are fitting a much lighter crank pulley then a lightened fly may actually be a positive thing

You forgot to mention balancer shaft deletion being bad too! Edit: removed technical explanation of engine balance and forces Flywheels are generally the weight they are to aide engine NVH and stability at idle - its cheaper than investing in other forms of engine damping As you say, it is only an opinion... Obviously one not shared by Courtenay who sell both lightened flywheels and underdrive pulleys, TMS who sell lightened flywheels, MMG who make the underdrive kit, me or anyone who has fitted an underdrive pulley - MMG or otherwise, or a lightened flywheel...

Edited by pjohn151, 24 September 2009 - 10:01 AM.

Thanks pjohn151, This guide is going to be extremely helpful today....I'm about to get under the car to fit my MMG pulley kit...I will have a laptop with your guide on it to help me along. Thanks again - very good of you to put this together. Adrian

Well, I managed to fit this kit, but it took a long long time....many hours of work involved. The car was out of action for one day...something to bear in mind if you're planning to fit this.

It must have been my unlucky day...here were my main problems during fitting:

• because my car is a stage 4 with a chargecooler...the chargecooler pipework got in the way of removing the top alternater bolts which are accessed from the engine bay. I had to remove some of the pipework to get at the bolts.
• there was a plastic cover over the top of the alternator...presumably to stop any water falling into the alternator. Again, this made the removal of the bolts at the top of the alternator very difficult.
• the original pulley was corroded onto the crankshaft. It took a few hours of tapping with a hammer/levering it off in what is quite a confined space.
• I had to take the centre section of my undertray off in order to get sufficient access to the orginal pulley to get it off. Might be down to my chargecooler positioning?
• after loosening the lower alternator 17mm nut / nearside helt bolt was extremely difficult to do it back up due to the limited access to the 17mm nut. I ended up having to use a chisel and socket set socket to jam the 17mm nut in place whilst tightening the nearside hex bolt. Very difficult in the confined space with only 2 hands! I would recommend you have a 17mm ratchet spanner like this before you start this job: Ratchet Spanners
• when putting the undertray back on, one of the captive nuts threaded itself .... a REAL pain....I had to rig up a temporary solution to get the undertray back on securely.
• my jack broke - it would no longer lift properly, then got stuck in the "up" position. Can anyone recommend a jack servicing place in London?

If you are going to do this, hope you don't have as many issues as I did! It's probably easier if you have somebody to help you - sometimes 2 hands are not enough!

I have a few photos which I'll post when I get time to help anyone else who's fitting one of these.

I am off to Spa on on Wednesday evening, so hoping to feel some improvements. Will report back.

Well, I managed to fit this kit, but it took a long long time....many hours of work involved. The car was out of action for one day...something to bear in mind if you're planning to fit this.

It must have been my unlucky day...here were my main problems during fitting:

• because my car is a stage 4 with a chargecooler...the chargecooler pipework got in the way of removing the top alternater bolts which are accessed from the engine bay. I had to remove some of the pipework to get at the bolts.
• there was a plastic cover over the top of the alternator...presumably to stop any water falling into the alternator. Again, this made the removal of the bolts at the top of the alternator very difficult.
• the original pulley was corroded onto the crankshaft. It took a few hours of tapping with a hammer/levering it off in what is quite a confined space.
• I had to take the centre section of my undertray off in order to get sufficient access to the orginal pulley to get it off. Might be down to my chargecooler positioning?
• after loosening the lower alternator 17mm nut / nearside helt bolt was extremely difficult to do it back up due to the limited access to the 17mm nut. I ended up having to use a chisel and socket set socket to jam the 17mm nut in place whilst tightening the nearside hex bolt. Very difficult in the confined space with only 2 hands! I would recommend you have a 17mm ratchet spanner like this before you start this job: Ratchet Spanners
• when putting the undertray back on, one of the captive nuts threaded itself .... a REAL pain....I had to rig up a temporary solution to get the undertray back on securely.
• my jack broke - it would no longer lift properly, then got stuck in the "up" position. Can anyone recommend a jack servicing place in London?

If you are going to do this, hope you don't have as many issues as I did! It's probably easier if you have somebody to help you - sometimes 2 hands are not enough!

I have a few photos which I'll post when I get time to help anyone else who's fitting one of these.

I am off to Spa on on Wednesday evening, so hoping to feel some improvements. Will report back.

Thanks pjohn151 for this excellent guide. Having just made this mod, I second what Dynamo says about chargecooler pipework getting in the way and removing the middle undertray, it makes access to the bolts a whole lot easier from underneath.

Not meaning to upset anyone, but I mentioned these to an engine developer today and they seemed to think they were a really bad idea - especially on an engine that doesn't run a dual mass flywheel

I'm looking at fitting one of these and have to say I'm concerned too, the original part appears to be the harmonic damper style of pulley (with the rubber sandwich tween inner & outer pulley components) which is there to kill any rotational harmonics that occur at certain revs etc, without that prevention in place crank fatigue could bring on a nasty failure. Most/all engines are fitted with a harmonic damper of one sort or another, even all the heavily tuned ones and there has to be a very good reason they go to all the aggro & expense of making and fitting them.
Has anyone covered large milage with one of these fitted? Bit scared of finding out the hard way.

I wonder if rather than fitting a smaller drive pulley to increase belt to component clearance, moving the alternator via a replacement mount might be a better fix? i.e., use the OEM pulley/balancer but shift the alternator a bit. Just a thought.

JF

Edited by jfvxt, 04 June 2012 - 07:06 AM.

Hi i think there are quite a few of us running the existing pully,you can retain it by fitting a modified bracket for the alternator with an elongated slot for adjustment on it and replacing the belt with a shorter one,there are clearance issues with the oil unions next to the pully but if you have made the bracket correctly this is fine.do a search there's a few threads about this mod,if you need help I'll take some photo' of the modded bracket so you have an idea. Check nev's engine build thread/web pages there's info on there as well.

Hi i think there are quite a few of us running the existing pully,you can retain it by fitting a modified bracket for the alternator with an elongated slot for adjustment on it and replacing the belt with a shorter one,there are clearance issues with the oil unions next to the pully but if you have made the bracket correctly this is fine.do a search there's a few threads about this mod,if you need help I'll take some photo' of the modded bracket so you have an idea. Check nev's engine build thread/web pages there's info on there as well.

Thanks for the reply
will look up the threads.

Jon

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Hi Guys,

Does anyone know the part number for a replacement belt in the Courtenay Sport under drive pulley?

Is it the same as the MMG version?

Thanks,

Jon

Hi Guys,

Does anyone know the part number for a replacement belt in the Courtenay Sport under drive pulley?

Is it the same as the MMG version?

Thanks,

Jon

If you have the oem tensioner in place you need a 5PK1645 belt

If you have the short belt mod with tensioner removed belt is 5PK858

DG