jlozinsk Posted May 7, 2012 Share Posted May 7, 2012 how light can i get the Nissan diesel crank? Quote Link to comment Share on other sites More sharing options...
josh817 Posted May 7, 2012 Share Posted May 7, 2012 Why not measure its mass, submerge it in some sort of liquid and see how much volume it displaces, and then calculate what the mass of a cubic centimeter of material is. Assume it's uniform density. Calculate the volume of material that will be removed if you gun drill it (obviously just volume of a cylinder). Total mass - mass of material removed = new mass? I'm not sure if it is proper or not to assume uniform density. I figure not, but it gets you in the ball park for sure. Or I mean, I guess someone could just give OP a real answer. Quote Link to comment Share on other sites More sharing options...
19762802+2 Posted May 7, 2012 Share Posted May 7, 2012 Well you could probably get it paper thin and it would be pretty light but who knows how long it would last, maybe longer then a R200 diff? who knows, You'll just have to try it and see how it goes. Quote Link to comment Share on other sites More sharing options...
johnc Posted May 7, 2012 Share Posted May 7, 2012 Mine was knife edged and lightened to 35 lbs. That was 17 lbs. lighter then stock. And the Japanese do not use the SAE grading system for steel. Quote Link to comment Share on other sites More sharing options...
josh817 Posted May 8, 2012 Share Posted May 8, 2012 John, I had read somewhere that these cranks shouldn't be lightened IF they are in sustained high RPM's, lets say 7000 and up due to harmonics. Since gun drilling is on the axis of rotation, removing weight from that location wouldn't be harmful like removing material from the counterweights would? Then again, I suspect gun drilling a crank would weaken the last rear main bearing where the crank snaps sometimes. I'm all curious now. Quote Link to comment Share on other sites More sharing options...
johnc Posted May 8, 2012 Share Posted May 8, 2012 If you run a good damper (like an ATI unit) that's custom spec'd for the crank you can lighten away. Quote Link to comment Share on other sites More sharing options...
TimZ Posted May 11, 2012 Share Posted May 11, 2012 If I'm reading the OP's original question correctly, it's worth pointing out that lightening the crank by gun drilling it will have virtually no effect on its rotational inertia. Quote Link to comment Share on other sites More sharing options...
Z Greek Posted May 12, 2012 Share Posted May 12, 2012 If I'm reading the OP's original question correctly, it's worth pointing out that lightening the crank by gun drilling it will have virtually no effect on its rotational inertia. Good Point, TimZ Quote Link to comment Share on other sites More sharing options...
Tennesseejed Posted May 12, 2012 Share Posted May 12, 2012 If you run a good damper (like an ATI unit) that's custom spec'd for the crank you can lighten away. In terms of fair market value (as opposed to trades or DIY) is this more, or less, than $2,000 in crank work? Absolutely beautiful. Do want. Quote Link to comment Share on other sites More sharing options...
Tony D Posted May 13, 2012 Share Posted May 13, 2012 (edited) Send and enquiry to Velasco's Crankshaft Service and you will get a precise price and not a ballpark guess. Edited May 13, 2012 by Tony D Quote Link to comment Share on other sites More sharing options...
BlueStag Posted May 22, 2012 Share Posted May 22, 2012 What benefit do you see in this process? As mentioned, you will be removing mass from the very center of the crank, so that should have no effect on how rapidly it spins up. And you surely are not doing this to lighten the car. You are proposing to remove metal from what is the very heart of the engine? Quote Link to comment Share on other sites More sharing options...
johnc Posted May 22, 2012 Share Posted May 22, 2012 In terms of fair market value (as opposed to trades or DIY) is this more, or less, than $2,000 in crank work? Absolutely beautiful. Do want. I don't know how much was spent specifically on the crank. I paid for a whole engine. I do know that it took two LD28 cranks to get one that stayed straight enough after Nitriding to be of use. The first one bowed and later sonic inspection found some porosity inside the number 3 main. Quote Link to comment Share on other sites More sharing options...
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