So whats the deal with knife edging the 4g64 cranks? what are the pros and cons on doing this mod? Been getting mixed answers on this.

 

i believe one of the pros for doing this is so that the knife edges reduces turbulence while rotating through the air/oil. Also helps reduced reciporicating mass as well. Will help achieve higher rpms as well. Someone let me know if im on the right path here

 

^yeah, it'll help the crank cut through the oil while it's rotating. But a con is that it will weaken the crank so you'll want to consult with a professional about this subject.

 

The idea is to speed up the rotation on the crank. This is great for all motor cars. Its a toss up on turbo cars because some people believe that while it causes the crank to speed up faster it also causes it to slow down faster between shifts which hurts spool time between shifts.

 

You get 2 benefits from knife edging a crank.

1st, the frontal area of the counter weight is reduced by "knife edging", making it easier to cut through the oil that is being spit out from all rod & main journal + the oil that is draining back from the cylinder head. This is where the power gains come from, the power is gained everywhere across the rev range, especially so as the revs increase.

2nd, the mass of the crank is reduced, allowing the engine to accelerate quicker. Not really generating more power, but think of it as removing weight from the car. You know how your car accelerates with 2 or 3 extra people in it, now just imagine the opposite.

As long as the crank is properly balanced, your crank should last just as long, if not longer if both cranks lived in the same environment.

The only downfall to removing weight from the crank, the engine wont idle as smooth. you'll get more of a lopey sensation from the engine.

 

Ahh, beavis4G63 and WOT. My two favorite Evo people giving their .02

 

this is very interesting, what is the cost of getting work like this done? and do any current tuner shops offer the service?

 

i used to get all my crank work on my race bikes by falicon in clearwater,fl. they do killer work, balancing, micro-polishing and knife-edging if you want. i think they do automotive cranks as well, i haven't checked. if they do auto work, i would highly recommend them.

 

this might be a bit offtopic, but does this have anything to do with "blueprinting"?

I've always heard the words "blueprinted" & "balanced" go together, when I read magazine articles and such.

What exactly does "blueprinting" mean? And how is the "balancing" done?

 

blueprinting usually refers to the assembly of the whole engine. as in measuring the crank journals instead of trusting or using the imprinted code stamped in the crank and installing the bearings in the engine, torque on bearing caps (without crank in) and measuring the inside diameter on the bearings. most good engine builders have their own preference for bearing clearances. also they weigh the assembled components; piston w/rings, wrist pin and con rod w/bolts get each bores reciprocating mass the same. it goes on and on like this w/each component like head, oil pump etc. the balancing of a crank is done on a big high tech machine like a lathe and they can get the balance with-in whatever. balancing, polishing and knife edgeing used to cost me $250 10 years ago from falicon.

 

awesome, thanks for the info puckadog!

 

thanks for the info guys... sounds like a good mod to do but I asked AMS and they said its not necessary. The AMS 900whp car uses a 4g64 drop in crank with no knife edging....

 

^ I wonder if they have actually tested one? If not, maybe the 900hp car could be making 950???? It is a noticeable difference in a SBC, but most of those rev to no more than 6500 RPMs and have a 50 year old oil drain and oil pan design. Maybe the 4G63 has made some advancements in oiling that keeps the crank from beating the oil senseless??

Anyone tried it yet?

EVOlutionary

 

This would be like one of the last mods you would ever do to an Evo.

 

Actually I feel it is a mod that, if proven effective, should or could be done for a little extra $$$ anytime you rebuild your engine. If for a couple hundred dollars you get a quicker rev, quicker spool, and a little more top end - I say it is worth it if you already have the motor torn down.

EVOlutionary