crank pulley question (oem & alloy)

[Chris 0]

is anyone using an aftermarket lightweight/alloy crank pulley? if so what do they run like in general and without the damper?

 

i need to replace my crank pulley as i suspect it is damaged and causing my belt squeak, vw sell the oem one for £240+ vat, mjm autohaus $299 which is better but the alloy ones are much cheaper still.

 

can anyone help? id like to use a genuine one but money is tight now and i have to fund a budget turbo project.

 

 

TIA

[flusted 0]

i ran 1 on my old 16v engine with no worries and i dont have the damper on my 16vg60 engine

[Philmo 0]

My understanding of crank pulley design is that the manufacturers select pulley mass and polar moment of inertia so as to optimally dampen crankshaft torsional vibrations!

So unless you've got a non-OEM crank, you're ill-advised to change the pulley.

If you've got a non-OEM crank then I guess advice should be taken from the manufacturer. Though this advice must coloured to some extent on what crank throw, rods & pistons you're running, also whether or not you've got a lightened flywheel.

Any further advice from our mech eng specialists??

[pete_griff 0]

it was my understanding that the pressure plate of the clutch was the thing that put the bottom end most out of balance...

 

maybe if you sorted the whole bottom end out at the same time - (lightened)/balanced flywheel, decent balanced aftermarket clutch (eg helix) and then put the pulley on, hopefully that would be ok longevity-wise....

ideally you would obviously have the crank/rods/pistons all balanced up at the same time; but failing that, as far as i know, it's the ancilliaries mentioned above that are the most detrimental to the balance of the bottom end...

 

(disclaimer!) please note, that none of that is in any way definitive, but that's just as i understand it; if anyone wishes to contradict/disagree with any of that, i'm all ears...

 

edit - i'm running neuspeed alloy pullies on mine with a helix clutch and autotech ally flywheel. if anyone does think i will have any issues with this, i would be very interested to hear. as i said, i was under the impression that everything would be fine, maybe even last a little longer; whatever - i'm hoping it will rev up like a chainsaw :D

[davidwort 0]

I don't think the revs you're likely to achive on a VR lump and/or the slight reduction in mass of the relatively small pulleys (compared to wheels, brake disks and flywheels) make the risk of using dubious quality/strength aftermarket pulleys worthwhile.

 

They might look shiny and colourful though :)

[pete_griff 0]

I don't think the revs you're likely to achive on a VR lump and/or the slight reduction in mass of the relatively small pulleys (compared to wheels, brake disks and flywheels) make the risk of using dubious quality/strength aftermarket pulleys worthwhile.

 

They might look shiny and colourful though :)

 

i didn't buy them to look shiny (they're matt black!) and besides hardly anyone will see them!

the standard pulley on the r32 (not running a VR) engine must weigh somewhere between 2-3Kg (haven't weighed it - but i was very surprised just how heavy it was) and the neuspeed one weighs a fraction of that (again haven't weighed it, but it's much much less).

that weight loss, combined with the lighter weight of an ally flywheel should make a noticable difference.

admittedly the chainsaw reference was a little OTT, but the diference running the whole lot together should be marked.

and the whole lot is properly balanced, so it should rev nice and smoothly as well.

 

also i wouldn't call the likes of autotech or neuspeed beginners in producing aftermarket parts. the crank pulley i have looks to be sufficiently beefy to not splinter into 99999999 pieces...

check it out - viewtopic.php?f=11&t=62901&st=0&sk=t&sd=a&start=60

 

just my 2p

 

thanks for the response though - any other comments welcome :)

 

edit - also if i remember correctly (not 100% certain but still - ) the standard r32 pulley doesn't have the dampener part in it like other pullies; i think it's just 100% metal

i will need to confirm that the next time i go out to the house though....

[davidwort 0]

my real point is that you don't get much of a reduction in rotational mass from pulleys, they're just too small in diameter to start with, every gram makes a difference on a race car but it's not going to be noticable on a (rarely revved to) 6,000 rpm road car.

[pete_griff 0]

my real point is that you don't get much of a reduction in rotational mass from pulleys, they're just too small in diameter to start with, every gram makes a difference on a race car but it's not going to be noticable on a (rarely revved to) 6,000 rpm road car.

 

that's a very valid point - i guess it depends what you want from the car and how you drive it.

 

i really should have weighed the difference between the standard and the neuspeed items as i was very surprised at just how much of a difference there was. it would be interesting to hear from any standard r32 owners who have gone for the aftermarket pullies; as i recon that you could notice a difference (albeit probably a very small one) just by changing the pulley alone. (the neuspeed ally PAS pulley that comes in the kit is an underdrive item anyway, obviously helping the difference further...)

from pullies alone, the difference will probably be minor, if at all noticable. when you combine that with different flywheel/clutch etc, i guess that's when it's going to far more noticable. i would really like to compare the difference with the way my car will run once it's all sorted hopefully after this weekend with a standard r32 corrado...

KipVR - you need to get yours finished asap! :)

[dukest 0]

If anybody reading this wants decides they want one then I have a brand-new unused Gruvenparts alloy crankshaft pulley for sale. :)

[Philmo 0]

my real point is that you don't get much of a reduction in rotational mass from pulleys, they're just too small in diameter to start with, every gram makes a difference on a race car but it's not going to be noticable on a (rarely revved to) 6,000 rpm road car.

 

Absolutely.

 

AND - that rotating lump of OEM iron is there for a reason!

[flusted 0]

Isnt another point that most of these alloy pulleys are slightly smaller than standard to underdrive the ancillaries?

 

Im using a mk3 1.4 crank pulley and that had no damper

[davidwort 0]

Isnt another point that most of these alloy pulleys are slightly smaller than standard to underdrive the ancillaries?

 

I guess so,

VW put a bigger pulley on the 1.8 16v alternator for this reason (7200rpm red line), the 2.0 16v and 8v cars which redline lower, have smaller pulleys.

Perhaps it's better to put slightly larger pulleys on the ancilliaries than smaller ones on the crank??? - I wouldn't want to underdrive my waterpump for instance.

[pete_griff 0]

definitely agree with that - it would make sense to put a smaller one on the crank rather than elsewhere

[Chris 0]

If anybody reading this wants decides they want one then I have a brand-new unused Gruvenparts alloy crankshaft pulley for sale. :)

 

i may call dibs on that if i decide to go for a non oem pulley. how much do you want for it posted?

 

 

 

lol, interesting comments guys :) , i dont mean to be a killjoy but i just need to know whether anyone has any experience running one on a vr6? im not looking for performance, im running a standard 90k block (with arp rod bolts - thats all ive done to it) standard flywheel but i may shave a kg off of it in the near future.

 

i just want a solution to my belt squeak, everything has been replaced in the line but the squeak came back. the bloke who sold me the engine craned it up on the crank pulley and the gearbox, hence why its squeaking,i think its damaged the ribs slightly with all tht weight causing very quick belt wear (this is the last thing it can be! trust me :roll: ). the details of this are in one of my other threads.

 

please advise :confused4:

[flusted 0]

Isnt another point that most of these alloy pulleys are slightly smaller than standard to underdrive the ancillaries?

 

I guess so,

VW put a bigger pulley on the 1.8 16v alternator for this reason (7200rpm red line), the 2.0 16v and 8v cars which redline lower, have smaller pulleys.

Perhaps it's better to put slightly larger pulleys on the ancilliaries than smaller ones on the crank??? - I wouldn't want to underdrive my waterpump for instance.

 

They use smaller crank pulleys on flat 4 beetle engines so it doesnt use as much engine power turning the cooling fan.