KA24DE Bottom End Modifications

Advanced discussion of improving KA-T components
User avatar
Aaj2k5
240sx Wannabe
Posts: 112
Joined: Mon Dec 29, 2008 10:39 am
Location: Ontario, Canada

Post by Aaj2k5 »

At least this guy ^ can see the totality of my idea :D

DatzenMike is going to send me his spare crank when he has some spare time to find it. Woohoo - finally getting the ball rolling..
1973 Datsun 240Z KA24DET
Build Thread:viewtopic.php?t=52102&start=0&postdays= ... highlight=
User avatar
airman
KA-T.org OWNER
Posts: 2144
Joined: Tue Jun 16, 2009 12:51 pm
Location: Anderson, SC

Post by airman »

Aaj2k5 wrote:We have the beginnings of a database like that but its still pretty cruddy.

As far as revving 1000 rpm more thats not entirely the case. Yes the piston speed would be the same but you are saving it from the first, second and third order of harmonics caused by HCW cranks. This allows a higher piston speed to be used safely, as long as you have all necessary mods to continue at those higher speeds - forged rods, pistons, balanced assembly, valvetrain, massively better airflow through the head and i may go even as far as an ATI dampener when I push the limits of it.
Taking it deep dude, I like it! When do we get to see the Bode plots and Simulink setups? :D
User avatar
Aaj2k5
240sx Wannabe
Posts: 112
Joined: Mon Dec 29, 2008 10:39 am
Location: Ontario, Canada

Post by Aaj2k5 »

Piston speed for L20B/KA at 9K would be just a hair faster than a stock S2000, so very doable.

Bode plots will come after my dynamics course this summer LOL.
1973 Datsun 240Z KA24DET
Build Thread:viewtopic.php?t=52102&start=0&postdays= ... highlight=
User avatar
Kfred
Belongs To The TOP CONTRIBUTING MEMBERS!
Posts: 3513
Joined: Sun Oct 29, 2006 8:12 am
Location: Baton Rouge, LA

Post by Kfred »

airman wrote: Taking it deep dude, I like it! When do we get to see the Bode plots and Simulink setups? :D
Generally I hate matlab. Simulink is pretty cool with its block diagrams though. I have only used it for advanced process controls of chemical systems.

I think 2.2l is the perfect displacement for a forced induction 4cyl engine.
RIP Nate(480sx)...
ka-torqy
Knows Some Stuff About 240's!
Posts: 282
Joined: Sat Nov 24, 2007 6:27 pm

Post by ka-torqy »

THIS IS SOO DAM EXCITING any update on this!!!???
and **** i didnt know BC sold fully counterweighted crank wit our stock stroke...if this doesnt work out then ill jsut go wit BC....but ive been wanting to rev the KA to 8k-9k....very doable just need good solid build!!! and TUNE! of course
Jus14
Knows Some Stuff About 240's!
Posts: 372
Joined: Mon Sep 21, 2009 2:25 am
Location: Cookeville,TN

Post by Jus14 »

Nice! i hope this works haha keep us updated
Zip Tie Racing
www.NissanNation.com
Image
User avatar
airman
KA-T.org OWNER
Posts: 2144
Joined: Tue Jun 16, 2009 12:51 pm
Location: Anderson, SC

Post by airman »

Any updates, good sir?
ICEMAN.KCMO
Knows Some Stuff About 240's!
Posts: 435
Joined: Sun Nov 12, 2006 8:33 am
Location: Kansas City, MO
Contact:

Post by ICEMAN.KCMO »

Ceiling cat will be watching this one...
Steve.
User avatar
Aaj2k5
240sx Wannabe
Posts: 112
Joined: Mon Dec 29, 2008 10:39 am
Location: Ontario, Canada

Post by Aaj2k5 »

Hey guys - I am afraid I am on hold for this task for a couple months while I'm back in school for the summer. Minimal hours at work + mountains of school work means minimal budget and time for the KA/240Z.

Come August I'll be back into this full time again so no worries :D. However if someone wants to find me a L20B crank in the mean time it would save me a fair bit of time/effort :D
1973 Datsun 240Z KA24DET
Build Thread:viewtopic.php?t=52102&start=0&postdays= ... highlight=
JankiS13
Driving Mom's Station Wagon
Posts: 46
Joined: Sat Nov 13, 2010 2:46 pm

Post by JankiS13 »

Unfortunately, if you do some searching around, you can find that the KA24E and KA24DE crankshafts have a main bearing diameter of 2.3609 the L20B's is 2.1631 so a crank swap is out.

Sorry dude, I was excited about this too.
Friends don't let friends buy knock-offs.
User avatar
Aaj2k5
240sx Wannabe
Posts: 112
Joined: Mon Dec 29, 2008 10:39 am
Location: Ontario, Canada

Post by Aaj2k5 »

JankiS13 wrote:Unfortunately, if you do some searching around, you can find that the KA24E and KA24DE crankshafts have a main bearing diameter of 2.3609 the L20B's is 2.1631 so a crank swap is out.

Sorry dude, I was excited about this too.
I can almost safely say I've done the most searching around for this particular project than anyone on here except for Datzen Mike.

L20B is not 2.1631. L16,L18 etc is.
I have spent hours looking at bearing catalogues - here is Clevite Mahle's just as an example.
http://www.mahleclevite.com/publications/EB-10-07.pdf

Page 567, block style 10.

10
1952CC (2.0L) L20B 4 Cyl (1974-1980) 3.346in./85mm x 3.386in./86mm
1952CC (2.0L) Z20 4 Cyl (1983-1985) 3.346in./85mm x 3.386in./86mm
1952CC (2.0L) Z20E,Z20S 4 Cyl (1980-1981) 3.346in./85mm x 3.386in./86mm
2187CC (2.2L) Z22 SOHC 4 Cyl (1981-1983) 3.425in./87mm x 3.622in./92mm
2187CC (2.2L) Z22E SOHC 4 Cyl (1982-1983) 3.425in./87mm x 3.622in./92mm
2389CC (2.4L) Z24/Z24i 4 Cyl (1983-1989) 3.504in./89mm x 3.780in./96mm


Main Bearing Set TM-1 MS-2042P STD,.25mm,.50mm,.75mm

1 MB-2885P 2.3599/2.3604 0.0007/0.0024 0.0722 2.5057/2.5062 1.0240
2-3 MB-2886P 2.3599/2.3604 0.0007/0.0024 0.0722 2.5057/2.5062 0.9450
3 MB-3519P(F) 2.3599/2.3604 0.0007/0.0024 0.0722 2.5057/2.5062 1.2580
5 MB-2888P 2.3599/2.3604 0.0007/0.0024 0.0722 2.5057/2.5062 1.0240


Compare those to the KA24DE numbers and you should be pleasantly surprised.

I still need an L20 crank though - coop starts in T-minus 1 month 1 week woohoo..
1973 Datsun 240Z KA24DET
Build Thread:viewtopic.php?t=52102&start=0&postdays= ... highlight=
JankiS13
Driving Mom's Station Wagon
Posts: 46
Joined: Sat Nov 13, 2010 2:46 pm

Post by JankiS13 »

Datzen Mike himself said that. I guess he could be wrong as well. I hope it does work out, I'd love a cheap FCW crank.
Friends don't let friends buy knock-offs.
User avatar
Aaj2k5
240sx Wannabe
Posts: 112
Joined: Mon Dec 29, 2008 10:39 am
Location: Ontario, Canada

Post by Aaj2k5 »

Datzenmike
User avatar

Joined: May 2006
Posts: 3520
Location: Van. Isle.

Post Re: High RPM KA24DE... With L20B crank
Image

L20B and Z22 cranks.

My mistake here. The L16/18 are 2.16 mains. L20B/Z20/Z22/Z24/KA24e are 2.36" mains. Some manuals have the late L20B and all Z motors listed as the same as the L16/18 at 2.16". I have a Nissan FSM for the '84 720 truck and the mains are listed as 2.16". I have measured two Z24 cranks and both were 2.36". It's all very confusing and I regret any confusion I may have caused.
http://www.the510realm.com/viewtopic.ph ... 7&start=30

Please read entire threads before claiming things that aren't necessarily true - I've done my research lol. I probably wouldnt have even started if the journals were off by 200 thou.
1973 Datsun 240Z KA24DET
Build Thread:viewtopic.php?t=52102&start=0&postdays= ... highlight=
drunknmunky
Knows Some Stuff About 240's!
Posts: 448
Joined: Sat Oct 08, 2005 2:13 pm

Post by drunknmunky »

Hey mate.

What kind of Stroke/rod ratio are you looking at with a K20 fcw?
vladt3
Dreams of owning a 240!
Posts: 71
Joined: Sun Aug 30, 2009 3:20 pm
Location: kolima,col

Post by vladt3 »

rather use rod from 5.4 ford,, best cut the block,, what do you think??
User avatar
Aaj2k5
240sx Wannabe
Posts: 112
Joined: Mon Dec 29, 2008 10:39 am
Location: Ontario, Canada

Post by Aaj2k5 »

drunknmunky wrote:Hey mate.

What kind of Stroke/rod ratio are you looking at with a K20 fcw?
KA24 + L20B = KA22 -> K20 is honda crap :P

It would be 169.1mm for the 5.4 rod/86 mm stroke = 1.96 to 1. Pretty high, but F1 4 bangers run over 2:1 all the time. You can bring that ratio down a bit with a different rod, but your compression goes to ****. Stock I believe is a 1.72:1 which is fairly ideal, but then you're still stuck with a HCW crank or over $2000 bill for just the BC stock FCW crank

I'll take the higher ratio though - here's a quick read for some peeps \/. With forced induction and proper headwork, its not nearly as big a problem as with NA.
Higher ratio engines, on the other hand, don't have the same friction concerns, but compromise in other areas. Air does not fill the intake ports with the same velocity, and there is less demand for the ports to flow as well since there is more time to fill and scavenge the cylinder (we discuss this phenomenon later). This typically means stagnant airflow at low revs and weaker torque. Hey, you can't have it all.

Longer rods also give the pistons more "dwell," the brief periods of time the piston is at top dead center and bottom dead center. A longer dwell allows for better flow of intake and exhaust gases since the piston moves slower between up- and downstrokes.
Longer dwell also offers more time to fill the cylinders during the intake stroke and more time to scavenge during overlap. And since the piston hangs out at or near TDC longer, the combustion stroke has more time to deliver a thorough release of energy on to the piston.
In a stroked motor, the piston ultimately reaches greater speeds to cover the additional stroke. The speed makes intake, compression and exhaust strokes more turbulent and, consequently, more powerful. It also comes with its price in component wear, something to consider when looking into parts that increase stroke.
With a short stroke and a long rod, however, the piston accelerates more gently from TDC. It picks up its greatest speed further down the bore, at the point where the crank pin relative to the rod angle reaches 90 degrees. Since the pistons move from TDC slower, the entire bottom end absorbs less mechanical stress.
vladt3 wrote:rather use rod from 5.4 ford,, best cut the block,, what do you think??
Vlad - not really sure what your asking.. you shouldn't have to modify the block at all..
1973 Datsun 240Z KA24DET
Build Thread:viewtopic.php?t=52102&start=0&postdays= ... highlight=
JankiS13
Driving Mom's Station Wagon
Posts: 46
Joined: Sat Nov 13, 2010 2:46 pm

Post by JankiS13 »

I must have missed that post, my bad! Good looking out.

I'm excited for this! I've been looking all over for L20 cranks, and I only found one "refurbished" one on ebay.

Do you know what material/construction the L20B crank is? Hopefully forged steel like the KA and SR cranks.
Friends don't let friends buy knock-offs.
User avatar
Aaj2k5
240sx Wannabe
Posts: 112
Joined: Mon Dec 29, 2008 10:39 am
Location: Ontario, Canada

Post by Aaj2k5 »

datzenmike wrote: L20Bs have an excellent forged steel fully counter weighted crank and strong rods.
I have a place to buy them for fairly cheap, but I'm gonna wait until I buy two for myself before I share :D Sorry guys, but don't want to put all this work into this and have em gone before I buy em lol.
1973 Datsun 240Z KA24DET
Build Thread:viewtopic.php?t=52102&start=0&postdays= ... highlight=
drunknmunky
Knows Some Stuff About 240's!
Posts: 448
Joined: Sat Oct 08, 2005 2:13 pm

Post by drunknmunky »

sorry. I didn't mean to mean K20.

Anyhow.

Have you calculated your mean piston speed with the ratio?
User avatar
superDorifto
Dont Question My Nissan Knowledge
Posts: 508
Joined: Tue Oct 11, 2005 6:58 pm

Post by superDorifto »

JankiS13 wrote:I must have missed that post, my bad! Good looking out.

I'm excited for this! I've been looking all over for L20 cranks, and I only found one "refurbished" one on ebay.

Do you know what material/construction the L20B crank is? Hopefully forged steel like the KA and SR cranks.
use car-parts.com, best junkyard database that I have ever seen. found a bunch of L20B cranks for under $100...complete motor sets too.

That is my go to resource for hard to find stuff.
User avatar
Aaj2k5
240sx Wannabe
Posts: 112
Joined: Mon Dec 29, 2008 10:39 am
Location: Ontario, Canada

Post by Aaj2k5 »

drunknmunky wrote:sorry. I didn't mean to mean K20.

Anyhow.

Have you calculated your mean piston speed with the ratio?
Mean piston speed is based on stroke, not the ratio

MPS = 2*(Stroke/1000)*RPM/60 = 2*86/1000*8000/60 = 22.9 m/s at 8000 rpm, 25.8 at 9000, which is almost dead perfect (similar to S2000).

Carparts is good for used parts, I'm getting L20B cranks refurbished to OEM specs for same as that.
1973 Datsun 240Z KA24DET
Build Thread:viewtopic.php?t=52102&start=0&postdays= ... highlight=
User avatar
superDorifto
Dont Question My Nissan Knowledge
Posts: 508
Joined: Tue Oct 11, 2005 6:58 pm

Post by superDorifto »

as long as the motor that it came out of didnt eat a bearing there isn't much to do to a used crank to get it back into spec....

Youre gonna have to mic it out to know what bearings to buy anyway.

I was just listing it as a resource for people that don.t know.
User avatar
Aaj2k5
240sx Wannabe
Posts: 112
Joined: Mon Dec 29, 2008 10:39 am
Location: Ontario, Canada

Post by Aaj2k5 »

superDorifto wrote:as long as the motor that it came out of didnt eat a bearing there isn't much to do to a used crank to get it back into spec....

Youre gonna have to mic it out to know what bearings to buy anyway.

I was just listing it as a resource for people that don.t know.
That's fair, I've found a ton of parts for my Jeep on the Canadian Carparts site.

Now hopefully can use KA performance bearings on the L20 crank - all I've found are OEM bearings specifically for the L20 crank.

Guess I'll find out when I blueprint the L20 crank when I get it. My biggest foreseeable issue is the width of the journals are wider on L20 compared to KA.
1973 Datsun 240Z KA24DET
Build Thread:viewtopic.php?t=52102&start=0&postdays= ... highlight=
User avatar
superDorifto
Dont Question My Nissan Knowledge
Posts: 508
Joined: Tue Oct 11, 2005 6:58 pm

Post by superDorifto »

Aaj2k5 wrote:
superDorifto wrote:as long as the motor that it came out of didnt eat a bearing there isn't much to do to a used crank to get it back into spec....

Youre gonna have to mic it out to know what bearings to buy anyway.

I was just listing it as a resource for people that don.t know.
That's fair, I've found a ton of parts for my Jeep on the Canadian Carparts site.

Now hopefully can use KA performance bearings on the L20 crank - all I've found are OEM bearings specifically for the L20 crank.

Guess I'll find out when I blueprint the L20 crank when I get it. My biggest foreseeable issue is the width of the journals are wider on L20 compared to KA.
I'm sure that I am not the only one following this build. I bought an L20B for gits and shiggles, interested to see what mods need to happen to make this work. I've 3 extra KAs and a ton of down time.

August is right around the corner.
drunknmunky
Knows Some Stuff About 240's!
Posts: 448
Joined: Sat Oct 08, 2005 2:13 pm

Post by drunknmunky »

Got a good redline.

So you cannot use the KA clevite 77's because of the bearing width differences as identified on 510.

Why not get the stock L20 ones and test it out. can't cost that much.
User avatar
Aaj2k5
240sx Wannabe
Posts: 112
Joined: Mon Dec 29, 2008 10:39 am
Location: Ontario, Canada

Post by Aaj2k5 »

superDorifto wrote:
I'm sure that I am not the only one following this build. I bought an L20B for gits and shiggles, interested to see what mods need to happen to make this work. I've 3 extra KAs and a ton of down time.

August is right around the corner.
Yep 4 wks of school left until I'm free :D

If you have the desire / downtime and wanted to toss a L20B crank in a KA and take some pics that'd be epic.

Any chance one of ur KA's is out of a frontier? I need some main caps rather than girdle.

Drunknmunkey yeh the crank I'm buying comes with a set of sealed power OEM L20 bearings so I'll try them out.
1973 Datsun 240Z KA24DET
Build Thread:viewtopic.php?t=52102&start=0&postdays= ... highlight=
User avatar
superDorifto
Dont Question My Nissan Knowledge
Posts: 508
Joined: Tue Oct 11, 2005 6:58 pm

Post by superDorifto »

Frontier KAs?

Unfortunatley no, I have an s14 in my kouki (obv) 2 s13s and another s14 sitting in my basement.

I just ordered the crank, and its coming from a wrecking yard in Arizona, so as soon as it gets here I'll snap some pics.
JankiS13
Driving Mom's Station Wagon
Posts: 46
Joined: Sat Nov 13, 2010 2:46 pm

Post by JankiS13 »

Aaj2k5 wrote:
superDorifto wrote:as long as the motor that it came out of didnt eat a bearing there isn't much to do to a used crank to get it back into spec....

Youre gonna have to mic it out to know what bearings to buy anyway.

I was just listing it as a resource for people that don.t know.
Unless you get hardcore and send it to Castillo.
Friends don't let friends buy knock-offs.
drunknmunky
Knows Some Stuff About 240's!
Posts: 448
Joined: Sat Oct 08, 2005 2:13 pm

Post by drunknmunky »

can you pm me here or on SON with regards to where you purchased the crankshaft from? I'd also like to request the spreadsheet and I put down a inquiry if you could help me out with the solidworks model.

I have a spare block and if my stock stroke fcw ka doesn't work out, theres always a fallback.

What kind of Rod's would you be looking @ and @ what length?

threadjack: how's that b15 treating you btw? :endjack.
User avatar
Aaj2k5
240sx Wannabe
Posts: 112
Joined: Mon Dec 29, 2008 10:39 am
Location: Ontario, Canada

Post by Aaj2k5 »

drunknmunky wrote:can you pm me here or on SON with regards to where you purchased the crankshaft from? I'd also like to request the spreadsheet and I put down a inquiry if you could help me out with the solidworks model.

I have a spare block and if my stock stroke fcw ka doesn't work out, theres always a fallback.

What kind of Rod's would you be looking @ and @ what length?

threadjack: how's that b15 treating you btw? :endjack.
Sorry dude I haven't been on SON in a while didn't even see ur posts there - yah I'll pm u tomorrow

I'm thinking Pauter X beams and factory Ford Modular 5.4 length 6.6xx" I think

B15 is hilarious to drive lol handles like a gokart-I've been pulled over 5 times since I got it just for being low, no tickets as of yet :D
1973 Datsun 240Z KA24DET
Build Thread:viewtopic.php?t=52102&start=0&postdays= ... highlight=
Post Reply