TopDawg_43 Posted May 25, 2006 Report Share Posted May 25, 2006 Here is a couple of pics of my knife-edged crank. I hope the performance gains are worth the $400 it cost me. http://pic19.picturetrail.com/VOL1039/1790846/9871119/149626134.jpg http://pic19.picturetrail.com/VOL1039/1790846/9871119/149626131.jpg http://pic19.picturetrail.com/VOL1039/1790846/9871119/149626129.jpg Link to comment Share on other sites More sharing options...
Indiana Posted May 25, 2006 Report Share Posted May 25, 2006 probably, I talked to race engineering in florida about doing that, they said it was mostly old thinking to do that and didn't reccomend it said it wasn't doing that much but that bullnosing was the way to go. I have a bullnosed crank but I would still like to try that Link to comment Share on other sites More sharing options...
chiplee Posted May 25, 2006 Report Share Posted May 25, 2006 looks good, just out of curiosity how much lighter is it? and are you planning to use a crank scraper? Link to comment Share on other sites More sharing options...
TopDawg_43 Posted May 25, 2006 Author Report Share Posted May 25, 2006 looks good, just out of curiosity how much lighter is it? and are you planning to use a crank scraper? Have not weighed it yet. It's still at the machine shop. It's ready but the block ain't ready yet (waiting on freeze plug kit). Picking it all up Tuesday after work. Yes, I plan to use a crank scraper. Link to comment Share on other sites More sharing options...
propeine Posted May 25, 2006 Report Share Posted May 25, 2006 Always wanted to try that. For 400 dollars you better see some gains....sheesh Tom Link to comment Share on other sites More sharing options...
TopDawg_43 Posted May 25, 2006 Author Report Share Posted May 25, 2006 Let me be clear, that $400 includes knife-edging, polishing, and balanceing to rotating assembly. Link to comment Share on other sites More sharing options...
artinist Posted May 25, 2006 Report Share Posted May 25, 2006 hmm, maybe i am confused here. someone correct me if i am wrong. isn't knife edgeing supposed to be on the leading and trailing edges of the crank that first dip into the oil and then out. its basically to reduce the power loss due to friction of it hitting the oil at high rpm? this looks more like a guillotine. to me its like installing an aerodynamic rear passender window. and just on one side. Link to comment Share on other sites More sharing options...
Chad Posted May 25, 2006 Report Share Posted May 25, 2006 I thought the same thing about the leading edge, but clearly that design will also reduce rotating mass (quite a lot), which will all by itself increase HP. Having the outtter edge cut like that will still accomplish most of the effect of reducing oil contact, as most of the contact occurs on the outter most edge anyway, where the oil level is above the lowest point of the couterweight orbit. Having all the mass removed, then rebalnaced and polished for $400 is a great price. Link to comment Share on other sites More sharing options...
heefner Posted May 25, 2006 Report Share Posted May 25, 2006 It looks good. I have often thought about doing that. Between that and a light weight fly wheel you should be revving to 7k really quick. If you plan on using a crank scraper you will have to make your own. I don't believe anyone sells one for a knife edged crank other wise you will be running a triangle through a square hole which really won't help "scrape" anything off the crank. Link to comment Share on other sites More sharing options...
cheaterparts Posted May 25, 2006 Report Share Posted May 25, 2006 hmm, maybe i am confused here. someone correct me if i am wrong.isn't knife edgeing supposed to be on the leading and trailing edges of the crank that first dip into the oil and then out. its basically to reduce the power loss due to friction of it hitting the oil at high rpm? it does look to remove a lot of weight does it balance up ok ? and it looks like there is still a lot of weight left around the big end journals would this change the balance factor or is it being used with lighter rods I must say I will be talking to my balancing guru on this as it looks and easy way to get more weight out of the crank as most of the work would be done on the lathe cheater Link to comment Share on other sites More sharing options...
TurboRaider@work Posted May 26, 2006 Report Share Posted May 26, 2006 The balance will still be ok ( or close to it ) because the counter weights are opposed to each other by 180º. What was removed off of one side of the crank was removed off the other. 4 Cyl cranks are not balanced using any bob weights, they just spin the crank, it will look fine on the balancer. However the counter weight at each rod journal does isolate forces locally, It’s there to counteract the weight of the rod / piston assembly. Since a good part of that is now gone more of the force to balance out the mass of one piston going down will be another piston going up. There is no reason this can’t work, but the mains bearings will be taking more of a load, as will the crank itself. A way to get some balance back is to drill out the id of the rod journals. If you look at some race cranks you can see how much they hollow out that area. Some counter weight removal is good esp with the lighter forged pistons. Kevin C Link to comment Share on other sites More sharing options...
Indiana Posted May 26, 2006 Report Share Posted May 26, 2006 I got this crank, I called and asked that place in florida what knife edge meant and they called what you pictured knife edged but called this one bullnosed and they didn't reccomend knife edging anymore but I would still like to try one. The machine shop here made a ford 2.3 stroker motor and knife edged that crank and got the motor up to a 2.9 (and you thought they complained too much about aluminum flywheels) http://www.b2600turbo.com/images/moddedcrank.jpg Link to comment Share on other sites More sharing options...
TurboRaider Posted May 26, 2006 Report Share Posted May 26, 2006 http://members.cox.net/kevincar1/crank.jpgJust back from the nitriders http://members.cox.net/kevincar1/crank1.jpg Polished This is what I did to the TurboRaider crank. Cleanup of the cheeks with a die grinder, a little bit of rounding of the counterweights, ion nitrided and polished. Kevin C Link to comment Share on other sites More sharing options...
cheaterparts Posted May 26, 2006 Report Share Posted May 26, 2006 There is no reason this can’t work, but the mains bearings will be taking more of a load, as will the crank itself. A way to get some balance back is to drill out the id of the rod journals. yes I agree I also think the mains may suffer the 2 outter journals would be easy enough but the inner jounals will need a bit of thought some kind of ball type cutter in the mill I would like to get some more weight out of the crank though cheater Link to comment Share on other sites More sharing options...
Boosted_One Posted May 26, 2006 Report Share Posted May 26, 2006 Good man Dawg!!! Ya your going to notice a difference in that crank. It's lighter now and you will have less resitence in the sump because the crank will slice thru the oil. This is one thing I wish I would have done with mine. Looks great man! Link to comment Share on other sites More sharing options...
TopDawg_43 Posted May 26, 2006 Author Report Share Posted May 26, 2006 Thanks for all the replies. My machinest is a balance guru. Other shops bring all there balance jobs to him. So I know the balance job is top-notch. With the combonation of the crank and the Fidanza, I assume that I'll have a motor with a whole new attitude. I hope to have the motor assemblied, installed and running by Oct. I'll let y'all know how it goes. Link to comment Share on other sites More sharing options...
TopDawg_43 Posted May 26, 2006 Author Report Share Posted May 26, 2006 It looks good. I have often thought about doing that. Between that and a light weight fly wheel you should be revving to 7k really quick. If you plan on using a crank scraper you will have to make your own. I don't believe anyone sells one for a knife edged crank other wise you will be running a triangle through a square hole which really won't help "scrape" anything off the crank. On the crank scraper website, they say that I'd have to let them know that the crank is knife-edged. So I'm assuming that they would know what to do. Or I'd just that to send some pics to them. Link to comment Share on other sites More sharing options...
chiplee Posted May 26, 2006 Report Share Posted May 26, 2006 It looks good. I have often thought about doing that. Between that and a light weight fly wheel you should be revving to 7k really quick. If you plan on using a crank scraper you will have to make your own. I don't believe anyone sells one for a knife edged crank other wise you will be running a triangle through a square hole which really won't help "scrape" anything off the crank. On the crank scraper website, they say that I'd have to let them know that the crank is knife-edged. So I'm assuming that they would know what to do. Or I'd just that to send some pics to them. I think you'll find you have to send them the crank, vice just pics. Or at least a template that is basically a cut out of your machined areas Link to comment Share on other sites More sharing options...
TopDawg_43 Posted May 26, 2006 Author Report Share Posted May 26, 2006 Please describe the engine and vehicle you will be installing the scraper into and do not forget to mention if it has a non-standard stroke or knife-edged crank. We will also need your mailing address and a phone number if possible so that we can contact you directly if we have a question. I'll give them a call when I'm ready to order it, and see what is needed. Crank-Scraper Link to comment Share on other sites More sharing options...
Boosted_One Posted May 26, 2006 Report Share Posted May 26, 2006 With the combonation of the crank and the Fidanza, I assume that I'll have a motor with a whole new attitude. That motor ain't gunna feel like the old motor at all. Watch how fast that turbo comes online now... Link to comment Share on other sites More sharing options...
heefner Posted May 27, 2006 Report Share Posted May 27, 2006 Maybe they can send you a blank or partial cut piece. Most scrapers require filing to fit "right" it would just be a little more work on your end. I'm sure the end result will be nice. I would wait and put the scraper on while the engine is still on the stand. It makes it sooo much easier. Link to comment Share on other sites More sharing options...
TopDawg_43 Posted May 30, 2006 Author Report Share Posted May 30, 2006 I would wait and put the scraper on while the engine is still on the stand. It makes it sooo much easier. Engine has been out of the car since Oct. I start the rebuild, tonight afater I pick the engine up from the machine shop (after work). Link to comment Share on other sites More sharing options...
TopDawg_43 Posted May 31, 2006 Author Report Share Posted May 31, 2006 Finally got my block, crank, flywheel, pressure plate, and rods back home. The weight saving from the crank is some where around 4 pounds. I'm not sure how accurate my scale is. I know it's how off by 20 pounds when I weigh myself. But it said my crank weighs 36lbs. And it said that a stock crank weighed 40 lbs. My machinest said it took 8 hours to do the knife-edging and balanceing. Including the flywheel, I lost around 14 pound of rotating mass. Link to comment Share on other sites More sharing options...
heefner Posted May 31, 2006 Report Share Posted May 31, 2006 Thats a pretty good chunk of change right where its most noticable. It should rev pretty good. You may have to slip the clutch a little to get things moving though. Link to comment Share on other sites More sharing options...
gober803 Posted June 1, 2006 Report Share Posted June 1, 2006 Very impressive. I'm also curious to hear about the pro's and con's of this. Then I just have to find a machine shop around here capable to doing this. Chris. Link to comment Share on other sites More sharing options...
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