KA24DE Bottom End Modifications
At least this guy ^ can see the totality of my idea
DatzenMike is going to send me his spare crank when he has some spare time to find it. Woohoo - finally getting the ball rolling..
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
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Taking it deep dude, I like it! When do we get to see the Bode plots and Simulink setups?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.
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.
Bode plots will come after my dynamics course this summer LOL.
1973 Datsun 240Z KA24DET
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- Kfred
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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.airman wrote: Taking it deep dude, I like it! When do we get to see the Bode plots and Simulink setups?
I think 2.2l is the perfect displacement for a forced induction 4cyl engine.
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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 . However if someone wants to find me a L20B crank in the mean time it would save me a fair bit of time/effort
Come August I'll be back into this full time again so no worries . However if someone wants to find me a L20B crank in the mean time it would save me a fair bit of time/effort
1973 Datsun 240Z KA24DET
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I can almost safely say I've done the most searching around for this particular project than anyone on here except for Datzen Mike.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.
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
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http://www.the510realm.com/viewtopic.ph ... 7&start=30Datzenmike
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Post Re: High RPM KA24DE... With L20B crank
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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.
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
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KA24 + L20B = KA22 -> K20 is honda crapdrunknmunky wrote:Hey mate.
What kind of Stroke/rod ratio are you looking at with a K20 fcw?
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.
Vlad - not really sure what your asking.. you shouldn't have to modify the block at all..vladt3 wrote:rather use rod from 5.4 ford,, best cut the block,, what do you think??
1973 Datsun 240Z KA24DET
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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.
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.
I have a place to buy them for fairly cheap, but I'm gonna wait until I buy two for myself before I share Sorry guys, but don't want to put all this work into this and have em gone before I buy em lol.datzenmike wrote: L20Bs have an excellent forged steel fully counter weighted crank and strong rods.
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- superDorifto
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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.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.
That is my go to resource for hard to find stuff.
Mean piston speed is based on stroke, not the ratiodrunknmunky wrote:sorry. I didn't mean to mean K20.
Anyhow.
Have you calculated your mean piston speed with 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
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- superDorifto
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That's fair, I've found a ton of parts for my Jeep on the Canadian Carparts site.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.
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
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- superDorifto
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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.Aaj2k5 wrote:That's fair, I've found a ton of parts for my Jeep on the Canadian Carparts site.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.
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.
August is right around the corner.
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Yep 4 wks of school left until I'm freesuperDorifto 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.
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
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- superDorifto
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Unless you get hardcore and send it to Castillo.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.
Friends don't let friends buy knock-offs.
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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.
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 tomorrowdrunknmunky 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.
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
1973 Datsun 240Z KA24DET
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