turbosi03

I have two cranks... b16a2 stock (left in pic), and an integra LS crank that has been knife edged.





It's going in a b16a2 motor, and I know the knife edge trick is usually for NA builds, but has anyone had good or bad experiences with this type of crank in a turbo setup?

VNTEC

All its really doing is makign it rev A LOT quicker, any mass u take off the crank all acts in the same way, for example a crank pulley, flywheel, and then ur crank. Some say it throws ur crank off balance and ruins the bearings, in my opinion, running a knife edge ona boosted car is overkill, its mainly for N/A Cars that like to rev 10k or so

Nick7

Also - less mass = more vibrations

turbosi03

ok so if it's overkill, do you think I would run into problems using this crank? the reason is I have crower rods to go with it... I want to use these parts and I don't think the crower rods can be used with the stock b16 crank because they were part of a stroker kit... am I right?


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Nick7 &raquo;</TD></TR><TR><TD CLASS="quote">Also - less mass = more vibrations</TD></TR></TABLE>

can this be fixed with using a harmonic balencer?

rioninja

Yes, it could be counteraced a little bit with a balancer.
Knife edging is a throwback to the days when the cranks used to actually come in
contact with the oil in the pan. Our hondas have windage trays, and a sump setup
that places the crank higher and away from the oil. The only advantage you could
see from running a knife edged crank is because of the reduced mass. IMO, if you
are looking to reduce mass, you are 100% better off using a lighter flywheel. You
will get about the same effect, and a flywheel is a hundred times easier to balance
than a crank.

Muckman

iTrader: (2)

good info.

turbosi03

so it sounds like there's not much benifit and can give me vibration issues... although I had this crank running before and didn't seem to have problems other then sleeves moving. I want to do this build right, but have to stay low as I can on budget.

so the question is should I use this crank or sell it to an NA guy, and buy another LS crank so I can keep the stroke?

mitsuman

iTrader: (1)

well since its a bit overkill for yout turbo setup, i say sell it or trade it for a stock ls + money. that way your getting some cash for it and youl still get the crank you need.

turbosi03

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mitsuman &raquo;</TD></TR><TR><TD CLASS="quote">well since its a bit overkill for yout turbo setup, i say sell it or trade it for a stock ls + money. that way your getting some cash for it and youl still get the crank you need. </TD></TR></TABLE>

yeah thats what I was thinking... but Earl and Mr Benson brought to my attaintion that the crank was knife edged so it would clear the oil squirters... the LS crank has more mass I guess.

so I'm assuming I can still swap in a stock LS crank but remove the oil squirters... I see on here some people remove them, some people leave them on... I'll do some searching but can anyone enlighten me on the pro's and con's of no oil squirts?

or link me to a good thread?

Thanks!

98gsrTEG

knife edgeing is a very good idia....if you have a muscle car were the crank actully sits in oil. hondas have a windage tray so it is %100 unnesasary for that aspect.
you will get small windage benifits from it and you will reduce the wieght of it, but it is not very safe and cost efective. if you want a faster reving car get a lightend flywheel. taking material off the crank isd the last place you want to take material out of to get less rotational mass

*Boostwerks*

Actually, most of the top named engine builders that I know of say its just a waste of money.

Vince reccomends just a good micropolish, and balance.

The oil squirters are just there to cool down the cast pistons. I have been told by Earl him self, that they are not needed with forged pistons. That oil could be better suited to keeping the bearings nice and lubed.

Turbo E

I agree with bryson and 98gsrTEG. wieght taken off the crank is faily negligable. all the mass is in the flywheel.

also you probably ended up just weakening the crank.

good luck with it anyways.

DaX

iTrader: (1)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Bryson &raquo;</TD></TR><TR><TD CLASS="quote">The oil squirters are just there to cool down the cast pistons. I have been told by Earl him self, that they are not needed with forged pistons. That oil could be better suited to keeping the bearings nice and lubed. </TD></TR></TABLE>

Exactly. If you're running forged pistons, the oil you keep off by NOT using the squirters will actually reduce the weight of the pistons by a few grams. Every little bit helps. If I had a VTEC block with forged internals, I would not use the squirters.

Br1t1shguy

What motor ever had a crank that was submerged in oil?

The point of knife edging is to reduce windage losses. The crank doesnt have to literally be in the oil to face a shitload of drag.

If you could look inside a crankcase at high RPM, what you would see is a cyclone of oil vapor. This creates alot of drag on the crank. Windage trays are there to keep the crank from whipping up too much oil, scrapers are there to take of the oil filam that covers the crank, and knife edging lowers weight and to some extent the "wind resistance" of the crank.