fully counter-wieghted crank clearancing

ViperGT · Post by **ViperGT** » Tue May 22, 2012 10:02 pm

well ive been planning on a ka-t build and have my engine out of the car and was working with a tight budget but now its a bit looser if i sell my dads Harley which my mom wont ever let me ride and id prefer a crotch rocket any ways but past the garbling. i want a super bullet proof revving ka and i havent been able to find any knowledgeable info on clearancing the block for a fully counter weighted crank. a magazine build showed only slight girdle and the bottom of the block were main supports are, grinding, but i thought i recalled another build which required the piston squirters to be deleted which i say is a no no for a ka-t. any help would be great especially pictures.

beercandrifter · Post by **beercandrifter** » Wed May 23, 2012 5:43 am

what constitutes a super revving ka?

500hpKA240sx · Post by **500hpKA240sx** » Wed May 23, 2012 8:29 am

billet balanced crank with the flywheel, forged rods, forged pistons,.....and most important full synthetic oil and you can rev it all you want and you wont hurt it in anyway. like beercan said im not too sure what you mean by a super revving ka either. :/

TheOne · Post by **TheOne** » Wed May 23, 2012 8:53 am

i didn't think you would have to clearance a FCW crank.

aren't brian crower fcw cranks drop in? i could see where it might need some clearancing now but didn't think that was the case.

btw i think importdps revved their ka to 10k rpm when they made that 1000rwhp run, that was with stock crank but modified main griddle with added support, and that was only like 1 or 2 runs, lol. i hope you're not shooting for 10k, but then ka should be able to do 8k easily if you get your head/intake mods to support flow at that range.

ViperGT · Post by **ViperGT** » Wed May 23, 2012 9:11 am

Yeah I just want to hit 8k with a nice flat torque curve and I don't want to have to worry about the harmonics

beercandrifter · Post by **beercandrifter** » Wed May 23, 2012 9:48 am

no flat torque curves on this motor

can hit mid 7krpm on stock head components, granted new springs and cams never hurt anyone

precision balancing makes a huge difference the faster you rotate.

why not just buy an sr or get a honda if you want a high revving engine? seems kinda silly to do all the work just to rotate fast, especially with a perfectly usable 6500-7000rpm power band

also the stroke is pretty much maxed on the ka crank, would be much easier to rev higher with a shorter stroke crank, granted there isnt one for our motor readily available

ViperGT · Post by **ViperGT** » Wed May 23, 2012 10:49 pm

haha cause everyone has a ***** sr and hondas are fwd and GAY. i want a bad ass KA and a fullycounter weighted crank keeps the torque linear through 9-10k in any any na engine. The ka only keeps torque up to 6-7k when boosted because the boost hides the real power curve. if you take 2 ka's (na) one with stock crank and the other with fcw crank the stock torque curve begins to fall after 4.7k because of half couterwieghted harmonics the engine with the fcw crank will carry the torque up through the revs. i am planning on porting the bowl/valve cut (biggest gain here), with ferrea inconel exhaust valves and bc intake with v3 cams and springs. the fully counterweighted crank will also bring change the powercurve when boosted.

wesamiss · Post by **wesamiss** » Wed May 23, 2012 11:35 pm

couldnt a machine shop balance the crank with your pistons, rods, and flywheel? no need to buy a pricey one when balancing costs $150 ish.

right?

YouTube Channel · Post by **supakat** » Thu May 24, 2012 4:39 am

Balancing is good but as great like knife edging.

beercandrifter · Post by **beercandrifter** » Thu May 24, 2012 5:42 am

cant say i have seen or read about any person with a ka hit 9k before, but would be interesting to see it actually last.

would be opting for some extremely light alloy engine internals (crank, rods, pistons)

what about the fueling, will injectors for the ka be able to manage pulsewidth at that range? would have to take into account all the ignition in the tuning

not saying dont go for it, just think theres alot to take into consideration.

YouTube Channel · Post by **supakat** » Thu May 24, 2012 6:07 am

supakat wrote:Balancing is good but as great like knife edging.

*Not as good as knife edging.

ViperGT · Post by **ViperGT** » Thu May 24, 2012 1:43 pm

i only want to take ka to 8k everyonce and a while, i was just making a point about tourque curves and how they follow through with a fcw crank to 9-10k on any engine. Balancing a stock crank is not as good as a fcw crank, half weight cranks(stock) actually kinda distort at higher rpms because the weight is only on half the side. Fcw cranks allow more rpms, and more accurate ignition timing.

ka-torqy · Post by **ka-torqy** » Thu May 24, 2012 11:54 pm

you can take the ka crank up to 8k...they do say anything after 7400rpm is when they start to see un wanted harmonics......however.....balance the crank pistons and rods, flywheel and get good bearings, and i hihgly suggest fluidamp damper and im pretty dam sure your good for taking it to 8k....and knife edging also helps as well....

but deff the fluidamp damper....balanced pistons, rods, crank, and aflywheel

correct me if im wrong, but im pretty dam sure youll be good with that setup

fcw are awesome but not worth it in price unless your going to 9-10k wiht high hp goals

Niclas_AB · Post by **Niclas_AB** » Fri May 25, 2012 12:39 am

Does the crank really make that big of a difference for the torque curve? Of course the stroke and bore will make a difference but if you just consider fcw against half counter weights? Isn't more about intake runnerlength, cams and exhoust manifold length to get the power where you want to have it?

KYLEBRENAY · Post by **KYLEBRENAY** » Fri May 25, 2012 9:20 am

Niclas_AB wrote:Does the crank really make that big of a difference for the torque curve? Of course the stroke and bore will make a difference but if you just consider fcw against half counter weights? Isn't more about intake runnerlength, cams and exhoust manifold length to get the power where you want to have it?

Agreed. I always thought the torque curve is prodominently manipulated with the flowing characteristics of the head, intake, and exhaust. I have a fully balanced rotating assemply in my engine to the gram with a knife edged crank and the torque curve doesn't seem too much different than my old s13 that was stock balanced with some forged pistons, before i built my head that is.