Leadership Team SLR No.77 Posted November 16, 2005 Leadership Team Share Posted November 16, 2005 I'm about to have my K-series crank assembly balanced - crank, flywheel, clutch cover, front pulley - but I'm considering the merits of fitting an alloy front pulley in place of the steel brick. Obviously the rotational mass would be reduced, along with the alternator speed, but is there a down-side? Are there issues with the damping of the crank being reduced such that it could lead to problems? Any other possible sources other than Hellier, QED? Stu. Edited by - sforshaw on 16 Nov 2005 21:45:40 Link to comment Share on other sites More sharing options...
SimonMac Posted November 16, 2005 Share Posted November 16, 2005 Doesn't the R500 also use a smaller and lighter crank pulley? ISTR they're relatively cheap from Caterham compared to alloy variants since they're made of steel. Not sure about merits other than some reduction in rotational mass and a reduction in the alternator speed. Link to comment Share on other sites More sharing options...
Jason Plato Posted November 17, 2005 Share Posted November 17, 2005 Hmmmmmmmm look at these sexy pulleys here.............go on tell me you dont want one 😬 C7 TOP Powered by Hellier Performance 😬 South Wales AO Link to comment Share on other sites More sharing options...
Mike Bees Posted November 17, 2005 Share Posted November 17, 2005 Slobber... A plus point for both the ali pulleys shown in Dave's pic and the Caterham steel one is that they gear down the alternator. My alternator is doubly geared down since I have the Caterham steel crank pulley and a large diameter dural pulley on the alternator. Still seems to charge OK. Mike Link to comment Share on other sites More sharing options...
mav Posted November 17, 2005 Share Posted November 17, 2005 Doesn't the R500 also use a smaller and lighter crank pulley? ISTR they're relatively cheap from Caterham compared to alloy variants since they're made of steel They are bloody heavy and were 50 odd quid + vat last time I bought one... Link to comment Share on other sites More sharing options...
Jason Plato Posted November 17, 2005 Share Posted November 17, 2005 The pulley above are in the region of 400g 😬 I have run with one for the past 12 months using a std rover alternator and charging has been fine C7 TOP Powered by Hellier Performance 😬 South Wales AO Link to comment Share on other sites More sharing options...
7 wonders of the world Posted November 17, 2005 Share Posted November 17, 2005 I looked at the alloy version, though after speaking to Steve @ Vibration free, his experience was of inconsistent machining. His advice to me was run the standard pulley, providing it's in good order as the torsional damping properties are beneficial on a road going engine in terms of longevity, even for 8000+rpm. Naturally if your running Pace DS you need to machined the power steering drive off hence saving a little weight and since the front pulley is a relatively small diameter the benefits are negligible anyway. Though the anodised ones do look sexy !! Link to comment Share on other sites More sharing options...
caterhamnut Posted November 17, 2005 Share Posted November 17, 2005 When our 'standard' steel and rubber one 'fell-off', I was stunned at the weight of the thing. www.mycaterham.com here 88,500 miles -1st 1.6k Supersport, '95 Motor Show car Link to comment Share on other sites More sharing options...
SimonMac Posted November 17, 2005 Share Posted November 17, 2005 Mav, is the R500 pulley no lighter than the standard pulley, and do you know the approximate weights of each if they differ? Link to comment Share on other sites More sharing options...
mav Posted November 17, 2005 Share Posted November 17, 2005 Not sure of specific weights, but the R500 Jobbie feels about the same as a bag of sugar... Link to comment Share on other sites More sharing options...
SimonMac Posted November 17, 2005 Share Posted November 17, 2005 That sounds about the same as the standard pulley, which is a bit 🙆🏻 Link to comment Share on other sites More sharing options...
Jason Plato Posted November 17, 2005 Share Posted November 17, 2005 std K damper pulley was around 2Kg R500 steel small pulley was around 1Kg ally pulley was 400g Edited by - Dave Jackson on 17 Nov 2005 11:24:31 Link to comment Share on other sites More sharing options...
Myles Posted November 17, 2005 Share Posted November 17, 2005 FWIW, when I had my crank, R500 flywheel, clutch cover and pulley balanced when I built PSC, ( the pulley was the last item added to the assembly) - the pulley (standard from a scrappy) was well within tolerance (it brought the entire assembly up from 20gmm to 30gmm (or whatever the units are)). They are s*dding heavy though - especially when compared to the flywheel... I'd guess that if you got a well-machined alloy one and had the whole lot balanced, it should be fairly safe - my lot was balanced to at least 8krpm (8.5 IIRC) - and I only use 7.5 at most. Project Scope-Creep is live... Alcester Racing 7's Equipe - 🙆🏻™ Alcester-Racing-Sevens.com Edited by - Myles on 17 Nov 2005 11:59:26 Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted November 17, 2005 Author Leadership Team Share Posted November 17, 2005 Dave, that's was, was and was 😬 I assume that you mean "is" and you're still running the ally pulley? Do I take it then that as long as everything is balanced correctly there's no issue to worry about. I'm also planning to use an R500 flywheel therefore the general rotational mass should be reduced nicely (currently running a "standard" lightweight flywheel). Stu. Link to comment Share on other sites More sharing options...
Mark Durrant Posted November 17, 2005 Share Posted November 17, 2005 I have used a small ally front pulley with an R500 flywheel for the past two years but did take the precaution of having the bottom end balanced. No issues have been experienced and I retained the standard Rover alternator. I would point out that my engine only revved to approx 7,500rpm. Mark D Su77on Se7ens Link to comment Share on other sites More sharing options...
Jason Plato Posted November 17, 2005 Share Posted November 17, 2005 Yes - I have used the ally pulley all year with an all steel ballanced bottom end . I will continue to use the ally pulley next season too there is plenty of data on pulleys and the standard K series damper pulley in the archives. The pulley was £98 *thumbup* C7 TOP Powered by Hellier Performance 😬 South Wales AO Link to comment Share on other sites More sharing options...
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