Guest Anonymous Posted May 2, 2001 Share Posted May 2, 2001 Im getting closer, disassembled my 81ZXT, now im going to do 87mm JE forged pistons and matching rods. But what to do for a crank? i know stock wont cut it, hehe no pun intented. but billet cranks are 2500!!!! Need help. Quote Link to comment Share on other sites More sharing options...
randy 77zt Posted May 2, 2001 Share Posted May 2, 2001 the stock crank is good for 7000 rpms and 20 psi boost.i havent really heard of many people using after markit cranks.the oem crank just needs good prep work-like magnaflux,oil holes chamfered,balence and throws knife edged.on a high dollar engine you will have more chances of leaning out and burning a piston than breaking a crank. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted May 2, 2001 Share Posted May 2, 2001 What is the purpose and procedure for "knife-edging" the crank? Does it have HP advantages for NA/FI engines? Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted May 2, 2001 Share Posted May 2, 2001 In the crankcase there's often a mist of oil. As the crank spins it has to cut through that crap like a car driving in a hail storm, this is why some oil pans have screens and windage trays. Anyway, the knife edge helps cut through the goo at high RPMs. Yeah, it should make more power, the higher the RPM the higher the HP gain I'd exect. However, while it may be "more" HP I don't know how much more and it probably varies from one engine family to another. It might be as little as 5hp - probably not worth it in that case I doubt it would be as much as 20 though. Anyone ever seen a back to back comparison anywhere? Quote Link to comment Share on other sites More sharing options...
Drax240z Posted May 3, 2001 Share Posted May 3, 2001 Knife edging is usually reserved for those engines that are looking for every last ounce of power, IMHO. As far as the L28 crank, remember that it is a forged unit. Nissan is wonderful for always using beefy, forged cranks. I doubt you'll ever find need for a heftier crank, unless you want to go over 8000rpm. For an application over 400hp I would follow randy's suggestion. Save your money and spend it elsewhere! Quote Link to comment Share on other sites More sharing options...
Kevin Shasteen Posted May 3, 2001 Share Posted May 3, 2001 The local Import Salvage Yard I go to when I need a part has told me in the past that he's never had a request for the lower end of a Z. He's been in business since the early 70's & has purchased dozens of Z's. He says his calls, from all over the nation-as he advertises naionally, is always for cyl.heads; most people who run their Z's hard always warp a cyl.head. He also said he's never even heard of the bottom end of an Inline 6 Z engine letting go; to that-he's never even sold an entire engine-it's always a request for the cyl.head only. That alone should tell you how well built the bottom end of a Z is. Kevin, (Yea,Still an Inliner) Quote Link to comment Share on other sites More sharing options...
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