V7 SLR Posted August 30, 2001 Share Posted August 30, 2001 I (think I) know that the SLR flywheel is lighter than that used on the other K engined cars, but not the actual figures. As I'm taking the engine out this Autumn I though it might be the perfect opportunity to see if a lighter one still was available. What options are available? 1. Have mine lightened? Who and how much? What's involved? Do I need to have the flywheel balanced with my crank and rods? 2. Buy an R500 one? How much and what's the weight saving? 3: Buy a third party one? From whom and how much again? I don't yet want to go down the road that the clutch-thread guys have gone with their plate-sized flywheels and clutches. I want to retain my clutch, but decrease the time it takes for the revs to die at gearchange time. I've already got a new ECU which removes the "hang" time that the MEMS has engineered in. Link to comment Share on other sites More sharing options...
Peter Carmichael Posted August 30, 2001 Share Posted August 30, 2001 The SLR flywheel is the same as the Superlight flywheel. The R500 one is lighter. I wouldn't reckon there is much scope for lightening the SLR flywheel. It is cast and some of the sections are pretty thin already. The R500 flywheel is probably the one you are after. I believe it may now be the only light k-series flywheel spec that they do. Link to comment Share on other sites More sharing options...
V7 SLR Posted August 30, 2001 Author Share Posted August 30, 2001 OK, that at least takes away some of the options. It helps one to focus. What about balancing? Is it necessary to balance a flywheel with the crank etc..? Caterham say the R500 flywheel is 250 + vat, and the guy on the Parts counter I spoke to said he thought the SLR flywheel was a forged steel one too. He was prepared to weigh them both for me, but static figures don't mean much as it's where the material is removed is what's important. He also said he didn't think there was much difference in weight between them, although we both agreed it was impossible to qualify the savings until you knew where the material had been removed. So, anyone got any experience of both the SLR and the R500 flywheel? Anyone know of any alternative 3rd party supplier? I'd like to retain my standard clutch, if that's a consideration. Edited by - V7 SLR on 30 Aug 2001 12:48:55 Link to comment Share on other sites More sharing options...
oilyhands Posted August 30, 2001 Share Posted August 30, 2001 Dont overlighten a cast flywheel, it may burst and take your feet with it, consider the minimum thickness to be 11mm, any changes in section must be properly radiused. A steel flywheel can be made considerably thinner and can be relieved by drilling and slotting near the periphery. If the flywheel is already much lighter than stock there may be little to gain. You *must* rebalance the whole of the rotating assembly after altering any of the constituent parts, so a full dynamic balance of the crank / flywheel / clutch and front damper whould be done. QED do a number of flywheel options, one is specifically for the Caterham with standard clutch arrangements, check the weight and material distribution first, you may be buying what you have already.. Oily. Link to comment Share on other sites More sharing options...
R2D2 Posted August 30, 2001 Share Posted August 30, 2001 I would almost certainly fit a steel flywheel to replace the cast iron unit.I have this fear of cast iron flywheels having lost one in an Escort rally car a few years ago. The damage to the transmission tunnel was quite significant. Steel has a much better resistance to fatigue than cast iron and a higher Young's Modulus . Most steel flywheels used to be manufactured from EN8 (080M20 in modern terms)which should be a realistic strength improvement. Link to comment Share on other sites More sharing options...
V7 SLR Posted August 30, 2001 Author Share Posted August 30, 2001 Caterham parts guy thought the SLR flywheel was a steel one already. I'm not sure. I might just get some opinions during the time the engine will be in pieces. I'll put the flywheel in the boot and cart it round to see what other people think, but if I have to go so far as a rebalance (as I thought) then I will probably wait for another year or so, until I've saved up for a more interesting bottom end. Thanks for the responses. Link to comment Share on other sites More sharing options...
Stijn LUYCK 1 Posted August 30, 2001 Share Posted August 30, 2001 I had a R500 flywheel installed last month but was unable to measure the weight. From picking it up I can tell you that it is slightly lighter as a 1.4K racer-flywheel ... but not by much. The difference is on the outside of the flywheel. If you want I can send you a picture from the R500 one so that you can compare it with the one in your car. Link to comment Share on other sites More sharing options...
V7 SLR Posted August 30, 2001 Author Share Posted August 30, 2001 Stijn, that would be great thanks. Please send any piccies to watchman@totalise.co.uk Very kind. Link to comment Share on other sites More sharing options...
R2D2 Posted August 30, 2001 Share Posted August 30, 2001 It shouldn't be too difficult to tell the difference between steel and cast iron as the surface finish will give a good indication. It's difficult to describe but I could help out if you need. Link to comment Share on other sites More sharing options...
V7 SLR Posted August 30, 2001 Author Share Posted August 30, 2001 Stijn, Thanks for the pics. Very interesting. I've sent them off to a friend who may be interested too. Chris, Once the engine comes out, I'll be interested to weigh the whole thing and compare it to the pics Stijn sent to me. This'll be in November sometime. The engine will be in pieces for quite a while (until the new year at least) so I could bring the flywheel to one of the Brook meetings one's week. I might bring my De Walt too. We could drill a few holes in it. wink.gif Cheers. Link to comment Share on other sites More sharing options...
Tony Martyr Posted August 30, 2001 Share Posted August 30, 2001 Doing the wrong thing with a flywheel has horrible results. Reducing the inertia of the engine up to the clutch is not all beneficial to either the driver or the car. The R500 flywheel should have been optimised for that crank -rods -piston system but being made of steel it should at least be safe from either bursting or the starter ring coming adrift. I would make that choice. I think home modification of flywheels is asking for big trouble. My industry has a history of horrors thus caused particularly in engines worked by tuning shops and universities. Link to comment Share on other sites More sharing options...
V7 SLR Posted August 30, 2001 Author Share Posted August 30, 2001 I'd much rather buy a solution than have mine altered in any way. That said, it seems there will be a bit of engineering to do anyway, with the rebalancing of the crank et al, so I'll leave this for another upgrade session. Thanks. Link to comment Share on other sites More sharing options...
Peter Carmichael Posted August 31, 2001 Share Posted August 31, 2001 PTP do an ultralight flywheel with holes in it, but it might be for the large 1.8 size K, whereas Caterham's use the 1.4 pattern flywheel. Worth investigating. FWIW, balancing with the clutch and pulley on was not possible with my engine build. The register on the pulley is not good enough to guarantee that you bolt it on in the same place each time. I can't remember the reason for the clutch. I get the distinct impression of false accuracy being claimed for *full* balancing. Link to comment Share on other sites More sharing options...
R2D2 Posted August 31, 2001 Share Posted August 31, 2001 Balancing engines is a wonderful subject and could generate some great arguements. I think that when engine tuners quote for "balancing" they may be getting away with murder. I have never seen the grade of balance specified by any engine builder. Is it G1, G2.5, G6.3 or has it been put in a machine and messed about with? Will the unit be component balanced and then assembly trim balanced? Will the pistons and pins be match weighed and will the rods be weighed end to end? If an engine has been component balanced before a final trim balance it may be safe to fit a new clutch or pulley that has been component balanced to a fairly high standard. Surely the main problem occurs with a unit that has only been assembly balanced and the weights adjusted by grinding lumps off the crank. (I once bought an engine in this state and still have the crank as a reminder) The other interesting question is the type of balancing machine that is being used to do this type of work. In the days of the A series and pre-crossflow Ford engines the standard of production line balance and line boring was dreadful and remedial work was essential. If you visit a current main stream engine plant the standard of the fully automated balancing machines being used is very very high. They are fully computer controlled and acheive very high standards of balance and productivity. I was recently at a well known engine builders and was shown a 1960's Avery soft pedestal balancing machine with great pride. (This machine has been obsolete since the mid seventies when most companies switched to hard pedestal machines.) The machine hadn't been calibrated for about 10 years and I doubt if it could achieve any balance standard better than G6.3. I think that if I had a modern K series engine I would be very careful about who I trusted to improve on the standard level of balance (which is very high) as I am convinced many of the "experts" send them back in a worse conditon than when they leave the factory. Link to comment Share on other sites More sharing options...
Peter Carmichael Posted August 31, 2001 Share Posted August 31, 2001 So what you are saying is that V7 could bolt on a component balanced flywheel and the chances are it would be OK. Better than a nominal balance on equipment of unknown calibration, pedigree and operator knowledge. Link to comment Share on other sites More sharing options...
R2D2 Posted August 31, 2001 Share Posted August 31, 2001 I think I would worry about fitting a new component balanced flywheel unless I knew that the factory had component balanced at the manufacturing stage and I also knew the balancing standard that had been acheived. For example if the crank etc. had been component balanced to G6.3 and then assembly trim balanced to G6.3 it would be perectly safe to fit a new flywheel which had been component balanced to either G2.5 or better still G1, without re-balancing the assembly. If the unit had only been assembly balanced to G6.3 it would not be safe change any component without re-balancing the assembly because it would be difficult to identify where weight had been removed from and the balance level of individual components. I do believe that balancing a modern set of engine components on unknown machines which are poorly calibrated to unspecified balance levels is at best a waste of money and will probably reduce the overall balance standard. The point that I didn't make very well is that we all seem to take "balancing" on face value and don't pay enough attention to what is being done to the internals of our very expensive engines. Reputable companies such as Coventry Balancing will provide traceable balancing certificates for all components and assemblies that they balance. I don't know how much they charge for this additional service but when we are spending £5,10,15K on an engine it would be good information to have. I would always ask the company that was balancing my engine to meet a specific ISO G level and if they can provide a balance certificate. It is amazing how many engine balancers can't meet these requests and some are not familiar with the ISO. I would avoid this type of company like the plague. Link to comment Share on other sites More sharing options...
V7 SLR Posted August 31, 2001 Author Share Posted August 31, 2001 Blimey. I'm a bit out of my depth I reckon. I think I'll come visit you again Chris when I've enough readies to buy a new flywheel. Link to comment Share on other sites More sharing options...
TorAtle Posted August 31, 2001 Share Posted August 31, 2001 FWIW, I just swapped the old flywheel with the R500 one. Can't say I noticed more vibration at high revs (am I supposed to?). Don't think the R500 flywheel is worth the money on it's own. You still have the standard heavy clutch assembly which will be a bottleneck. It's an improvement though. I've seen Peter C's flywheel/clutch combo (picture only) and it looks fab. Anyone know an ultralight clutch assembly that can simply be bolted onto the R500 flywheel? Link to comment Share on other sites More sharing options...
V7 SLR Posted September 1, 2001 Author Share Posted September 1, 2001 Tor, what flywheel did you start with? As the SLR already starts with a lighter flywheel than standard I wonder if the difference between the two is even less than you experienced. If so, I won't bother. Link to comment Share on other sites More sharing options...
Stijn LUYCK 1 Posted September 1, 2001 Share Posted September 1, 2001 Nig, if you already have a light flywheel I would not bother spending £300 on the R500 one ... as Tor mentions more weight can be saved in the clutch assembly. For people who start from scratch the extra £50 over a standard light flywheel is something to consider. Link to comment Share on other sites More sharing options...
TorAtle Posted September 1, 2001 Share Posted September 1, 2001 I had the standard flywheel for a road 1.6K. Link to comment Share on other sites More sharing options...
CHRIS CLARK Posted September 2, 2001 Share Posted September 2, 2001 Well, I had the opportunity to sit in Peter C's car today when he brought it out for a shakedown run.I didn't drive it, but that clutch is amazing. I'm talking here about pure pedal movement terms. It seems to have about 70 mm of travel!!!!!! I'm sure Peter can give the exact distance, but it must be very 'switch' like. Good to see the Beast back on the road Peter {U] Link to comment Share on other sites More sharing options...
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