Riceburner Posted July 7, 2014 Posted July 7, 2014 What have you had done to your crankshaft during rebuild aside from balancing and oil plugs getting drilled and tapped? Pros and cons of lightening and knife edging? How light should you go? I saw Jason mention 15kgs before IIRC. Quote
NZeder Posted July 7, 2014 Posted July 7, 2014 15kg...will not be a LD28 at 15kg they start at 22kg you would not have a lot of LD28 left to get it down to 15kg. Quote
dat2kman Posted July 7, 2014 Posted July 7, 2014 I can shave three day stubble with my knife edging. And can lift a cardboard bxox containing ,y 6 pistons and rods, with my pinky finger.. Quote
Riceburner Posted July 7, 2014 Author Posted July 7, 2014 Sorry Jason, it was John C on a hybridz thread. 15.8kg is what he got it down to. http://forums.hybridz.org/topic/112410-knife-edge-crank/ Sounds like that is a very extreme weight reduction. What would a more normal amount be, 3-5kg? Quote
dat2kman Posted July 7, 2014 Posted July 7, 2014 Yeah Gareth, 3-5 kgs is about it, i have to use stock stroke L28 cranks in the Sc car, so they are a bit lighter than the LD jobbies. ( oh,, and isn't everything bigger better lighter fadter etc in the land of the World Series of everything,,,, that only gets played in that land !! - them Muricans!) Quote
dat2kman Posted July 7, 2014 Posted July 7, 2014 All up, i have taken a bit over 14 kgs out of the whole rotate/reciprocate mass, that is, front balancer, crank, rods pistons, flywheel and clutch assy. Combined, this gives good response to throttle, and there is still plenty torque, except for the funny little dip at around 4100, but that is a camshaft thing. All sucking through a single stock injection TB. Quote
d3c0y Posted July 7, 2014 Posted July 7, 2014 Les Collins can do you up a full counter weight billet crank! That's how they get the 3.5L, tell me bigger isn't better now Jason! Quote
NZeder Posted July 8, 2014 Posted July 8, 2014 Les Collins can do you up a full counter weight billet crank! That's how they get the 3.5L, tell me bigger isn't better now Jason! that would be nice and I am sure Jason would love to race a zed that large but SC rules dictate he has to use the L28 aka stock crank so he does the best he can for the class rules - that does not mean that all are playing the game correctly. I had a L28 crank that was down by about 3-4kg - can't recall now it was years ago this was in my ownership now in the engine bay of another 240z race car here in NZ. 35lb is 15.9kg is more like 16kg than 15kg too that is still 6kg out of the stock LD28 cranks which is a lot of metal. Quote
Riceburner Posted July 8, 2014 Author Posted July 8, 2014 Definitely agree Mike, I'm not brave enough to get it machined that much I'm guessing the 3.5L crank is beyond my budget Jake. I could be wrong but I thought the Kameari ones went for 6k? They also mention Nitriding in that Hybridz thread. Do any of you guys recommend or do this to your cranks? Quote
d3c0y Posted July 8, 2014 Posted July 8, 2014 My 3.35L crank was nothing like $6k, i'm pretty sure that the full billet counter weight 3.5L crank is only just that much. Don't forget shipping. As well all know a crank is only 1/10th of the story. Quote
dat2kman Posted July 8, 2014 Posted July 8, 2014 They are $7k from Crankshaft Engineering in Melbourne, will do what you want. Hollow pins, knife edged, full or partial weights, longer flywheel register, etc. Quote
Riceburner Posted July 10, 2014 Author Posted July 10, 2014 Has anyone tried Isotropic Finishing on internals? http://www.metalimprovement.co.uk/isotropic-finishing.html Looks very interesting, some fairly worthwhile benefits to the process which doesn't seem that expensive. I wonder if you could do bearing shells and rings too... http://www.hpsf.com.au/images/downloads/HPSF-Pricing-2014.pdf Quote
lampy Posted July 10, 2014 Posted July 10, 2014 I sent my brand new r180 5.1 R&P to be Isotropic Finished at neat gearboxes in SA. Haven't used the diff yet so cant comment on strength. Supposed to reduce oil temps as well Quote
Riceburner Posted July 11, 2014 Author Posted July 11, 2014 How was it cost wise Lampy? It may not be the correct wording but is it a permanent finish? E.G. If you don't use it for a while does the surface corrode again? Quote
lampy Posted July 11, 2014 Posted July 11, 2014 I think it was a few hundred for shot peening and finishing. Was packaged up in the total diff build so don't know exact numbers. Not really sure if it is a permanent finish. I would think so if it is not on a wearing surface Quote
peter mc Posted July 13, 2014 Posted July 13, 2014 The rb stroker setup is a hole lot lighter than a light 2.8 crank , as the pins are honda size , and the rods are light as well , lol and the piston because the pin hight is so high , and you get 250cc more than the best Ld crank kit , hole kit under 6000 , best hp around Quote
Riceburner Posted July 13, 2014 Author Posted July 13, 2014 The rb stroker setup is a hole lot lighter than a light 2.8 crank , as the pins are honda size , and the rods are light as well , lol and the piston because the pin hight is so high , and you get 250cc more than the best Ld crank kit , hole kit under 6000 , best hp around Thanks for bursting my bubble mate hehe. Here's hoping that sweet PMC power head will keep me in the ball park, if I ever race it again The tyres have gone square at the moment. So basically the 3.4 kit is much lighter and much more power and torque? Quote
peter mc Posted July 13, 2014 Posted July 13, 2014 Yes id never build a LD stroker , not in the hunt , , Quote
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