Let's talk Ka24 crank shafts and gurdles! - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

rb25_s13*CHUKI · 04-16-2012, 04:09 PM

So I've been looking at my ka crank shaft and wondering why nissan gave such a piece of CRAP crankshaft!!! They really did not care about the Ka at all! It's not fully counter weighted which is a big issue for vibration and high RPM. My crank weighs 35 lbs! Which isnt too heavy of a crank but thats because It's not full weighted!

Bc makes a fully countered crank and they say the weight out of the box is 45 lbs! Which is a PIG crank!! So heavy! Has anyone butchered a Bc Ka crank yet on this forum? What was the end weight and how do you like the crank? The crank Isn't a cheap one though! It has a nice price tag but It's billit and fully weighted so your ready to go with power and RPM!

If anyone has butchered one of these Bc cranks please let me know how you like it and how much weight did miss piggy loose! BUCHER A.K.A KNIFE EDGE.

Now on to the main gurdle! Why is is that the truck model Ka24de's have main bearing caps like the sr20 and the car model Ka24de's have a main gurdle? You would think they would put the stronger gurdle design on the truck which people would be using to haul stuff as oppose to the main cap design which Is suppose to be weaker?

That main gurdle is damn heavy piece and coule save weight in the engine is you can obtain a set of frontier ka main caps! Whats the significant difference? Sr20 use a crank girdle but not bridged mains they have single bearing caps. Does the truck Ka engines have the same type of setup? I've never seen inside of a frontier ka before.

Edwin562 · 04-16-2012, 04:17 PM

I never knew there was an aftermarket crank for the ka.. dope...

rb25_s13*CHUKI · 04-16-2012, 04:35 PM

Quote:

Originally Posted by Edwin562

I never knew there was an aftermarket crank for the ka.. dope...

Yea but it's pretty pricey!

Edwin562 · 04-16-2012, 04:36 PM

3k?? thats it?? pocket change homie... hahah

Brian Crower KA24DE Stroker Kits for your Nissan 240SX from HorsepowerFreaks

rb25_s13*CHUKI · 04-16-2012, 04:46 PM

Quote:

Originally Posted by Edwin562

3k?? thats it?? pocket change homie... hahah

Brian Crower KA24DE Stroker Kits for your Nissan 240SX from HorsepowerFreaks

Hahaha shit pocket change if only!, I've seen just the crank for 2k I think or like $1800

found it!

BC Part Number BC5219

I don't think the price is too bad if ur builing a ka! I'm sure someone has a hook up they can get this crank for like $1000

rb25_s13*CHUKI · 04-19-2012, 02:23 PM

up up and away

PoorMans180SX · 04-19-2012, 03:05 PM

The main girdle design is stronger period.

The BC crank is ridiculously priced. Do you know you have to chamfer the edges of all your bearings because they can't get the machining right?

They also make a stock stroke crank btw. Either way you have to machine your block for the new counterweights.

rb25_s13*CHUKI · 04-19-2012, 03:34 PM

Quote:

Originally Posted by PoorMans180SX

The main girdle design is stronger period.

The BC crank is ridiculously priced. Do you know you have to chamfer the edges of all your bearings because they can't get the machining right?

They also make a stock stroke crank btw. Either way you have to machine your block for the new counterweights.

Yea I heard you have to machine the block and I've been trying to find another crank but nobody has stepped up! I'm trying to find a local shop in L.A that could possibly make a legit crank!

I know the main girdle is stronger by design but why would nissan do it ass backwards? Main girdle on the Ka powered cars and Main cap on Ka powered trucks?

kamilitaryman · 04-19-2012, 03:37 PM

There was a fellow on Ka-t.org who started doing some math, not sure if he's still around, but this is the thread he started, trying to find a cheaper solution for the KA.

www.ka-t.org :: View topic - KA24DE Bottom End Modifications

PoorMans180SX · 04-19-2012, 03:38 PM

Because the 240 makes more power? Haha who knows.

There is talk on the ka-t forums of an old datsun crank working as a destroker fcw 2.2 crank.

EDIT: the above link.

If you really want a boss 2.4 liter engine, you'd run a 2.4 long rod 4g64 with a 63 head.

UNITEDMASTER · 04-21-2012, 12:25 AM

Im not too sure what it is your trying to acheive???? But if your trying to reduce rotating mass,just knife edge & dynamic balance the stock crank & rotating assembly plus the clutch & flywheel,if it is balanced properly ,it will not matter if it is fully counterbalanced. The fully counter balanced crank is gonna set you backwards in terms of weight,and possible clearence issues. And the bridged girdle is the way to go,but any form of girdle is better than none at all.

As far as the different girdle (car VS truck) I beleive it has to do with the usable RPM ranges of the different applications. Car= higher peak sustained RPM VS truck less peak RPM but higher torque output at lower RPM.Two different applications same engine. Just a thought my.02

PoorMans180SX · 04-21-2012, 11:36 AM

You sir, are wrong. Sorry. KA's bend cranks when spun to 8000rpm consistently, specifically because they are half-counterweighted.

AdamR · 04-21-2012, 03:41 PM

Quote:

Originally Posted by PoorMans180SX

You sir, are wrong. Sorry. KA's bend cranks when spun to 8000rpm consistently, specifically because they are half-counterweighted.

I have never once heard that. Sources?

PoorMans180SX · 04-21-2012, 07:42 PM

Quote:

Originally Posted by greaser

switched over to E85 picked up 10wheel hp over 100 octane tune. turned up the rev limiter cuz it was making power to 7500rpm.

then bent the crankshaft.

after the e85 tune i started to hear a hellacious racket if i revved and held the motor at about 3 grand. it was louder than my exhaust if that tells you anything.

checked valve lash........ok
checked leakdown.......9% ok
watched the crankpulley during idleing and it was all over the place. put another one on and same thing.

so i bent the snout. pulled the motor, the pan, the front covers, the clutch, the main seal, the girdle and ripped out the crank. the front main bearing looks funny but not ate up. swapping cranks and going racing in 2 days at VIR.

So basically, you might not bend your crank, but you will significantly shorten your bearing life.

UNITEDMASTER · 04-25-2012, 06:18 PM

Quote:

Originally Posted by PoorMans180SX

You sir, are wrong. Sorry. KA's bend cranks when spun to 8000rpm consistently, specifically because they are half-counterweighted.

OOOOOKK ,if you say so. Based on personal expirence(not hearsay) you gotta be doing big things obend a fuckin KA crank...... It is a forged peice SOOO ....... and what KA even makes power at 8 grand(unless its already a fully built/blueprinted motor with all the complimenting goods to go with it????

If your bending cranks ,I would have to say something is terribly wrong.

So please elaborate as to what I may have said that was wrong,Im always down to learn something new

Bent snouts come from bad/poor harmonics & guess what causes that hhmmmm

GroundPerformance · 04-25-2012, 06:23 PM

Same here.. This is actually interesting.

PoorMans180SX · 04-25-2012, 08:28 PM

Quote:

Originally Posted by UNITEDMASTER

OOOOOKK ,if you say so. Based on personal expirence(not hearsay) you gotta be doing big things obend a fuckin KA crank...... It is a forged peice SOOO ....... and what KA even makes power at 8 grand(unless its already a fully built/blueprinted motor with all the complimenting goods to go with it????

If your bending cranks ,I would have to say something is terribly wrong.

So please elaborate as to what I may have said that was wrong,Im always down to learn something new

Bent snouts come from bad/poor harmonics & guess what causes that hhmmmm

Greasers 235whp NA KA does, or should I say did for a short period of time.

Harmonics are inherent in a crankshaft rotating at speed . They are not something you can get rid of by having them balanced, and aftermarket dampers only help to a point. The harmonics in the KA crank do not like high-rpms, and the half-counterweighting only adds to the problem.

Cranks rotate in a jump-rope-like fashion. The main caps and girdle keep this controlled, but it still happens on a small scale. Half-counterweighting causes more flex in a crank by making the distance greater between weights.

UNITEDMASTER · 04-26-2012, 09:15 AM

True you will not get rid of harmonics 100% but anything done to reduce it will go along way,never said balancing would eliminate it. Moving parts will always have it to what degree ,how bad who knows. A fully balanced motor VS one that is not makes a world of differanc,when trying to acheive high RPM consistantly. I think most of the harmonics issue comes from flywheel/clutch assm. & the balancer at the front.

AdamR · 04-26-2012, 10:40 AM

Quote:

Originally Posted by PoorMans180SX

So basically, you might not bend your crank, but you will significantly shorten your bearing life.

He clearly had a bad balancer/crank pulley.

PoorMans180SX · 04-26-2012, 11:23 AM

Okay dudes, rev your KA's out as far as you want, I was just trying to throw down some facts but you guys clearly want to ride on your own theories.

You guys have probably never heard of someone cracking a KA block either, right?

Have fun!

iveexcaped3 · 04-26-2012, 12:20 PM

Quote:

Originally Posted by PoorMans180SX

Harmonics are inherent in a crankshaft rotating at speed . They are not something you can get rid of by having them balanced, and aftermarket dampers only help to a point. The harmonics in the KA crank do not like high-rpms, and the half-counterweighting only adds to the problem.

im just curious here, but if the half counterweights only make it worse cant you just get it fully balanced? wouldnt that help with the harmonic dislike for high rpm? i might be missing the whole conversation here but i thought id ask

UNITEDMASTER · 04-26-2012, 03:26 PM

HAHAHA dude your just reciting hearsay based off of what you read on the internets,& jumping into many different subjects at the same time. First you tell me Im wrong,then you recant,O you MAY not bend your crank,but you will reduce bearing life???.wich is true when you subject any motor to sustained high rpm. Even more so in a motor with a "relativly" long stroke. You cant ask something to do what it was not intended to do.

This whole disscusion could go on for days,my advice to anyone would be get a clear understanding of how different things work, draw your own conclusions,& make your own decisions.

Have fun!!!

Walperstyle · 04-26-2012, 03:34 PM

Don't get the stroker, you don't need it. Just take your stock crank to a good machine shop and get it balanced properly. But make sure when you do, send it in with some bearings, and get it micro-polished to fit them. (actually, the best way and cheapest way is to get the machine shop to fully assemble your lower end, I found this out the hard way and had to send my block in twice when I checked and found I was out of spec)

Its nice to believe you can build everything yourself. Take it from some of us that have done this, its sometimes doesnt work out as planned, and you end up spending hundreds/thousands more.

This is the proper way to do an engine build. We had a guy on ka-t . org that was going to prove how amazing the stroker kit is..... well, still waiting. lol.

PoorMans180SX · 04-26-2012, 11:15 PM

You're right, I'm retarded. Everyone revs their built KA's to 8k because they're so reliable at that speed. It would be easy to get a KA to make power up there btw.

Guys rev their 2.3 stroker 4g63's out to 8000rpm all the time, even though they have a 4mm longer stroke, and thus more piston speed. You know why? They have a fully-counterweighted crank.

Guys rev their stroker sr's out to 9k even though they have an absolutely terrible rod ratio. You know why? They have a fully counter-weighted crank.

Fully countered cranks are better. Period. Proven fact.

Here's the overall point: the crankshaft is the single largest hurdle a KA has to making big, smooth, reliable power after the puny 11mm head studs and crappy stock pistons.

AdamR · 04-27-2012, 10:03 AM

^I guess that's why the stock internals record was limited by the rods bending.

PoorMans180SX · 04-27-2012, 10:39 AM

Quote:

Originally Posted by AdamR

^I guess that's why the stock internals record was limited by the rods bending.

Yes because what we're talking about has anything to do with stock block records. I was just making a general statement. A couple spikes of detonation and the ring lands would have went before the rods could, and we all know that shotpeening the rods helps a lot if that's what you're into.

Let's keep this about the KA's crank and it's limitations eh?

AdamR · 04-29-2012, 12:18 PM

Quote:

Originally Posted by PoorMans180SX

Yes because what we're talking about has anything to do with stock block records. I was just making a general statement. A couple spikes of detonation and the ring lands would have went before the rods could, and we all know that shotpeening the rods helps a lot if that's what you're into.

Let's keep this about the KA's crank and it's limitations eh?

They are just as resilient as any other stock piston. Subaru engines have it even worse.You're right, the discussion isn't about stock block records. I was just pointing out the wrong information. That is a full time job here, though.

godrifttoday · 04-29-2012, 12:31 PM

Don't disregard "poorman180sx" comments, he started the roll center thread !!!! Jajaja

Walperstyle · 04-29-2012, 04:41 PM

^besides starting threads, has he actually built a KA yet, or is this just all theory.

Walk the line, then preach.

PoorMans180SX · 04-29-2012, 05:33 PM

I have friends that I have helped build KA-t's, as well as doing extensive research on tons and tons of NA and turbocharged KA setups, crankshaft design, harmonics, etc, etc. it's really not hard to come to a well-educated conclusion based on such things.

04-16-2012, 04:09 PM	#1
rb25_s13*CHUKI Post Whore! Join Date: Mar 2007 Location: Cali Age: 32 Posts: 2,759 Trader Rating: (16) Feedback Score: 16 reviews	Let's talk Ka24 crank shafts and gurdles! So I've been looking at my ka crank shaft and wondering why nissan gave such a piece of CRAP crankshaft!!! They really did not care about the Ka at all! It's not fully counter weighted which is a big issue for vibration and high RPM. My crank weighs 35 lbs! Which isnt too heavy of a crank but thats because It's not full weighted! Bc makes a fully countered crank and they say the weight out of the box is 45 lbs! Which is a PIG crank!! So heavy! Has anyone butchered a Bc Ka crank yet on this forum? What was the end weight and how do you like the crank? The crank Isn't a cheap one though! It has a nice price tag but It's billit and fully weighted so your ready to go with power and RPM! If anyone has butchered one of these Bc cranks please let me know how you like it and how much weight did miss piggy loose! BUCHER A.K.A KNIFE EDGE. Now on to the main gurdle! Why is is that the truck model Ka24de's have main bearing caps like the sr20 and the car model Ka24de's have a main gurdle? You would think they would put the stronger gurdle design on the truck which people would be using to haul stuff as oppose to the main cap design which Is suppose to be weaker? That main gurdle is damn heavy piece and coule save weight in the engine is you can obtain a set of frontier ka main caps! Whats the significant difference? Sr20 use a crank girdle but not bridged mains they have single bearing caps. Does the truck Ka engines have the same type of setup? I've never seen inside of a frontier ka before. __________________ Obliterate

04-19-2012, 02:23 PM	#6
rb25_s13*CHUKI Post Whore! Join Date: Mar 2007 Location: Cali Age: 32 Posts: 2,759 Trader Rating: (16) Feedback Score: 16 reviews	up up and away __________________ Obliterate

04-19-2012, 03:05 PM	#7
PoorMans180SX Zilvia.net Advertiser Join Date: Nov 2005 Location: Michigan Age: 33 Posts: 5,431 Trader Rating: (16) Rides Gallery: PoorMans180SX Feedback Score: 16 reviews	The main girdle design is stronger period. The BC crank is ridiculously priced. Do you know you have to chamfer the edges of all your bearings because they can't get the machining right? They also make a stock stroke crank btw. Either way you have to machine your block for the new counterweights. __________________ Build: http://zilvia.net/f/showthread.php?t=643065 Friends don't let friends buy knock-offs.

04-19-2012, 03:37 PM	#9
kamilitaryman Zilvia Junkie Join Date: May 2008 Location: Buffalo, NY Age: 38 Posts: 377 Trader Rating: (14) Feedback Score: 14 reviews	There was a fellow on Ka-t.org who started doing some math, not sure if he's still around, but this is the thread he started, trying to find a cheaper solution for the KA. www.ka-t.org :: View topic - KA24DE Bottom End Modifications __________________ 400HP KA24DET in progress

04-19-2012, 03:38 PM	#10
PoorMans180SX Zilvia.net Advertiser Join Date: Nov 2005 Location: Michigan Age: 33 Posts: 5,431 Trader Rating: (16) Rides Gallery: PoorMans180SX Feedback Score: 16 reviews	Because the 240 makes more power? Haha who knows. There is talk on the ka-t forums of an old datsun crank working as a destroker fcw 2.2 crank. EDIT: the above link. If you really want a boss 2.4 liter engine, you'd run a 2.4 long rod 4g64 with a 63 head. __________________ Build: http://zilvia.net/f/showthread.php?t=643065 Friends don't let friends buy knock-offs.

04-16-2012, 04:17 PM	#2
Edwin562 Post Whore! Join Date: Nov 2009 Location: Whittier (562) Age: 31 Posts: 4,721 Trader Rating: (35) Feedback Score: 35 reviews	I never knew there was an aftermarket crank for the ka.. dope...

04-16-2012, 04:36 PM	#4
Edwin562 Post Whore! Join Date: Nov 2009 Location: Whittier (562) Age: 31 Posts: 4,721 Trader Rating: (35) Feedback Score: 35 reviews	3k?? thats it?? pocket change homie... hahah Brian Crower KA24DE Stroker Kits for your Nissan 240SX from HorsepowerFreaks

04-21-2012, 12:25 AM	#11
UNITEDMASTER Nissanaholic! Join Date: Apr 2006 Location: Anaheim Posts: 1,626 Trader Rating: (10) Feedback Score: 10 reviews	Im not too sure what it is your trying to acheive???? But if your trying to reduce rotating mass,just knife edge & dynamic balance the stock crank & rotating assembly plus the clutch & flywheel,if it is balanced properly ,it will not matter if it is fully counterbalanced. The fully counter balanced crank is gonna set you backwards in terms of weight,and possible clearence issues. And the bridged girdle is the way to go,but any form of girdle is better than none at all. As far as the different girdle (car VS truck) I beleive it has to do with the usable RPM ranges of the different applications. Car= higher peak sustained RPM VS truck less peak RPM but higher torque output at lower RPM.Two different applications same engine. Just a thought my.02 __________________ MR JACKSON.

04-21-2012, 11:36 AM	#12
PoorMans180SX Zilvia.net Advertiser Join Date: Nov 2005 Location: Michigan Age: 33 Posts: 5,431 Trader Rating: (16) Rides Gallery: PoorMans180SX Feedback Score: 16 reviews	You sir, are wrong. Sorry. KA's bend cranks when spun to 8000rpm consistently, specifically because they are half-counterweighted. __________________ Build: http://zilvia.net/f/showthread.php?t=643065 Friends don't let friends buy knock-offs.

04-25-2012, 06:23 PM	#16
GroundPerformance Zilvia FREAK! Join Date: Oct 2008 Location: Socal Posts: 1,477 Trader Rating: (44) Feedback Score: 44 reviews	Same here.. This is actually interesting. __________________ SoCal KA24DET/KA24ET Owners << Join the FB Group >>

04-26-2012, 09:15 AM	#18
UNITEDMASTER Nissanaholic! Join Date: Apr 2006 Location: Anaheim Posts: 1,626 Trader Rating: (10) Feedback Score: 10 reviews	True you will not get rid of harmonics 100% but anything done to reduce it will go along way,never said balancing would eliminate it. Moving parts will always have it to what degree ,how bad who knows. A fully balanced motor VS one that is not makes a world of differanc,when trying to acheive high RPM consistantly. I think most of the harmonics issue comes from flywheel/clutch assm. & the balancer at the front. __________________ MR JACKSON.

04-26-2012, 11:23 AM	#20
PoorMans180SX Zilvia.net Advertiser Join Date: Nov 2005 Location: Michigan Age: 33 Posts: 5,431 Trader Rating: (16) Rides Gallery: PoorMans180SX Feedback Score: 16 reviews	Okay dudes, rev your KA's out as far as you want, I was just trying to throw down some facts but you guys clearly want to ride on your own theories. You guys have probably never heard of someone cracking a KA block either, right? Have fun! __________________ Build: http://zilvia.net/f/showthread.php?t=643065 Friends don't let friends buy knock-offs.

04-26-2012, 03:26 PM	#22
UNITEDMASTER Nissanaholic! Join Date: Apr 2006 Location: Anaheim Posts: 1,626 Trader Rating: (10) Feedback Score: 10 reviews	HAHAHA dude your just reciting hearsay based off of what you read on the internets,& jumping into many different subjects at the same time. First you tell me Im wrong,then you recant,O you MAY not bend your crank,but you will reduce bearing life???.wich is true when you subject any motor to sustained high rpm. Even more so in a motor with a "relativly" long stroke. You cant ask something to do what it was not intended to do. This whole disscusion could go on for days,my advice to anyone would be get a clear understanding of how different things work, draw your own conclusions,& make your own decisions. Have fun!!! __________________ MR JACKSON.

04-26-2012, 03:34 PM	#23
Walperstyle Nissanaholic! Join Date: Nov 2004 Location: Alberta, Red Derp Age: 40 Posts: 1,729 Trader Rating: (0) Feedback Score: 0 reviews	Don't get the stroker, you don't need it. Just take your stock crank to a good machine shop and get it balanced properly. But make sure when you do, send it in with some bearings, and get it micro-polished to fit them. (actually, the best way and cheapest way is to get the machine shop to fully assemble your lower end, I found this out the hard way and had to send my block in twice when I checked and found I was out of spec) Its nice to believe you can build everything yourself. Take it from some of us that have done this, its sometimes doesnt work out as planned, and you end up spending hundreds/thousands more. This is the proper way to do an engine build. We had a guy on ka-t . org that was going to prove how amazing the stroker kit is..... well, still waiting. lol. __________________ KA-T ORG-Function over Flush

04-26-2012, 11:15 PM	#24
PoorMans180SX Zilvia.net Advertiser Join Date: Nov 2005 Location: Michigan Age: 33 Posts: 5,431 Trader Rating: (16) Rides Gallery: PoorMans180SX Feedback Score: 16 reviews	You're right, I'm retarded. Everyone revs their built KA's to 8k because they're so reliable at that speed. It would be easy to get a KA to make power up there btw. Guys rev their 2.3 stroker 4g63's out to 8000rpm all the time, even though they have a 4mm longer stroke, and thus more piston speed. You know why? They have a fully-counterweighted crank. Guys rev their stroker sr's out to 9k even though they have an absolutely terrible rod ratio. You know why? They have a fully counter-weighted crank. Fully countered cranks are better. Period. Proven fact. Here's the overall point: the crankshaft is the single largest hurdle a KA has to making big, smooth, reliable power after the puny 11mm head studs and crappy stock pistons. __________________ Build: http://zilvia.net/f/showthread.php?t=643065 Friends don't let friends buy knock-offs.

04-27-2012, 10:03 AM	#25
AdamR Leaky Injector Join Date: Jan 2008 Location: Owensboro, KY Age: 37 Posts: 134 Trader Rating: (0) Feedback Score: 0 reviews	^I guess that's why the stock internals record was limited by the rods bending.

04-29-2012, 12:31 PM	#28
godrifttoday Post Whore! Join Date: Jan 2004 Location: los angeles Age: 37 Posts: 3,120 Trader Rating: (82) Feedback Score: 82 reviews	Don't disregard "poorman180sx" comments, he started the roll center thread !!!! Jajaja __________________ NEED Bolt kits for your car?

04-29-2012, 04:41 PM	#29
Walperstyle Nissanaholic! Join Date: Nov 2004 Location: Alberta, Red Derp Age: 40 Posts: 1,729 Trader Rating: (0) Feedback Score: 0 reviews	^besides starting threads, has he actually built a KA yet, or is this just all theory. Walk the line, then preach. __________________ KA-T ORG-Function over Flush

04-29-2012, 05:33 PM	#30
PoorMans180SX Zilvia.net Advertiser Join Date: Nov 2005 Location: Michigan Age: 33 Posts: 5,431 Trader Rating: (16) Rides Gallery: PoorMans180SX Feedback Score: 16 reviews	I have friends that I have helped build KA-t's, as well as doing extensive research on tons and tons of NA and turbocharged KA setups, crankshaft design, harmonics, etc, etc. it's really not hard to come to a well-educated conclusion based on such things. __________________ Build: http://zilvia.net/f/showthread.php?t=643065 Friends don't let friends buy knock-offs.

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