Hey guys, I did a search on this topic and found almost nothing. Can anyone give me some input on whether knife edged cranks are reliable on daily driven street cars? I know that alot of race engines do this to reduce windage losses but I was wondering if it might be a worthwhile mod for a street car engine build. I heard they may put added stress on the oil pump and bearings, is this true? Thanks for all replies.

 

for a street car i would leave the stock crank alone.......look into light weight pistons and rods......

 

Anyone else have some input. My setup is an ls/vtec with stock rods (arp bolts) and P30 pistons .25 over. That gives me 11.9 comp with stock headgasket. I've heard from some knife edging is a great way to make some more power. Trying to decide whether or not its beneficial or not? Help anyone?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EGgsrAM &raquo;</TD></TR><TR><TD CLASS="quote">Anyone else have some input. </TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by non-VTEC &raquo;</TD></TR><TR><TD CLASS="quote">for a street car i would leave the stock crank alone.......look into light weight pistons and rods...... </TD></TR></TABLE>

 

Honda builds their motors with a lot of weight on the center rotating assembly to help eliminate harmonics. This in turn gets you longer lasting and more reliable parts. The guys above are right, save weight on pistons and rods, but leave the crank alone.

 

Thanks for the all the responses. I'll leave mine untouched except for regular bottom end balancing and a micropolish on the journals. Thanks again . H-T is really helping out with my engine build

 

good call most knife edege cranks end in bearing falure unless you check after every race! and thats a race car!

 

crank for the street should be left alone. When racing that is another story. I my self just polish the journals.

 

personally, i'd say spend your money elsewhere.
the only way it would be alright imo, is if you have someone who will do it for cheap, and ALSO be sure to properly balance the rotating assembly.

but even then... there's been so many motors that made awesome power WITHOUT doing this.

so unless you're trying to break 250whp, i'd say steer clear.
200+ is easy without this mod, and even 220+ is still no prob.
this type of **** is strictly for motors @ 99% capability and need that extra push.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GoldenEagleMfg.com &raquo;</TD></TR><TR><TD CLASS="quote">Honda builds their motors with a lot of weight on the center rotating assembly to help eliminate harmonics. This in turn gets you longer lasting and more reliable parts. The guys above are right, save weight on pistons and rods, but leave the crank alone. </TD></TR></TABLE>

But you have knife edging in different degrees. You can go really far so that the ends become sharp like a knife or you can do it a little less. Just taking some wheight off without completly going all the way.

I haven't decided yet but i have street/strip engine built and the person that is building mine said a 'half' knife job wouldn't cost me relaibility.

It is for a gsr bottom end with eagle rods and wiseco pistons golden eagle resleeved 84.5 mm bore. And ofcousre everything balanced and bleu printed.

So what should i do, knife edge it or not ???

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rev limiter &raquo;</TD></TR><TR><TD CLASS="quote">But you have knife edging in different degrees. You can go really far so that the ends become sharp like a knife or you can do it a little less. Just taking some wheight off without completly going all the way.

I haven't decided yet but i have street/strip engine built and the person that is building mine said a 'half' knife job wouldn't cost me relaibility.

It is for a gsr bottom end with eagle rods and wiseco pistons golden eagle resleeved 84.5 mm bore. And ofcousre everything balanced and bleu printed.

So what should i do, knife edge it or not ???</TD></TR></TABLE>

I think everybody above have giving the answer to this topic. Do it for a race motor if you are trying to squeeze that last bit out of your motor. However...I would <U>never</U> do this mod to a daily grind. Spend the money else where!

 

The most I would go would be just to balance the crank, by knifing the crank your messing with its reliability, and on a daily driver thats half the battle.

 

if you dont retreat the crank it wont last very long trust me! when you take off any amount on the, crank the rotational might be ok after you build but wait till the crank starts distorting after the first 5 miles i know i have race motors that probably havent even lasted that long. do i need to post pictures? there ugly and i even started checking the bearings every race and still killed a fresh crank.

dont do it on a street car! i still have a customer making 230 fwp and 160 trq on a re treated (nitriated) crank. Car makes a ton of power all motor and on 86 bore but its not the most reliable set up. he rarley even drives the car. and these hp #'s are on a full exhaust.

 

My friend had a LS/V with a knife edge crank and he said he lost some power and ended up putting the stock crank back in. Maybe the shop he took it do didnt do a good job or something, but it was a complete was of time and money

 

actually you will make more trq. and less hpw, i take that trade anyday. but knife edgeing sucks for a street car dont do it! you be sorry for that 1/2 cut crank unless you treat the crank again.