High RPM KA24DE... With L20B crank

[dislexicdime]

now hug

[fo0manchu]

Sorry I was not paying attention yesterday.
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. Period. The rod diameters are the same though.
The L20B crank will swap into a Z20, Z22, Z24 block, so. All the previous post above will work with a Z24 block.

FIRST: sorry to resurrect this asinine thread 510rob!

But in case anybody is still reading this post, i just thought that i would mention that the main journals of the ka24e and l20b are the same, 60mm, so crank swap is not out. You can use the L20b crankshaft and ka bearings. If i had seen this thread awhile ago I would have chimed in. I have thought of this setup a long while back. L20b crank, super long rod, in a ka block. How do i know this? I have them sitting in my garage. I have the L20b crank in a Ka24e block with front cover on and pulley. Everything fits perfectly, like it was meant to be. I did measurements and research awhile back and found some H-beam rods for a mustang would fit with a little machining.

Anywho, this was one of those, "if i had spare money I would do it" kind of ideas because its "different". I said screw the idea and just dropped in a Ka24de turbo instead.

But if any of this is "top secret", go ahead and erase it...

[datzenmike]

Well I'll have to measure it again. I still say 2.36" give or take.

[datzenmike]

OK checked my KA24E crank and it's 2.36" mains and I even checked the girdle bearing's diameter. L20B mains are often mistakenly listed as 2.36" (my '78 FSM and Haynes manuals list them incorrectly) but in reality they are 2.1630", just like all L and Z series motors. So, if you have a KA motor, then you must have mixed up and put the KA crank back in OR if you have an L20B crank then you have it in a Z24 block.

KS crank in it's girdle:


The KA block has material that surrounds the starter...



From the rear it surrounds and covers the front of the transmission like this...

[fo0manchu]

Here you go, i measured it again. The main difference is the width of the journals. Perhaps my crank is just a fluke or your crank has been ground down?

Here is also a picture of the bearings next to each other.

Don't mind the ka24e crank, i have had this for awhile and had fun with a grinder awhile back.
But the ka24e came out of my friends 240sx. l20b crank on top, ka on bottom.

[datzenmike]

Well isn't that something? I have manuals that specify the larger 2.36" journal for the L20B. Other books like Haynes/Chiltons have coppied this. (misprint???) I have measured several L20B, 2 Z20, 2 Z22 and several Z24 mains and they are all 2.16". I'll investigate further.

What was that L crank out of? Could it be an LD20 diesel?

[fo0manchu]

that is weird. It is definitely out of a fuel injected setup. I forget what car, i had pulled it(l20b) out of a car in the junkyard probably about 5 years back.

Perhaps there was a year cutoff where the specs were different, or perhaps there were different specs depending on a different manufacturer plant??? That is pretty interesting though.

And I know you have probably looked at more crankshafts that i have.

[okayfine]

No EFI L20Bs were brought to the States. Z20 was the first EFI USDM four-cylinder.

[fo0manchu]

thank you for the correction okayfine, I had meant to say carbed. The first thing that came to mind instead of diesel was fuel injection, so thats what i typed. ooopsss.

[okayfine]

Have never seen an L20B EFI manifold. The "common" L-series fuelie manifold was the L18. Was going to be very interested in the EFI L20B bits.

Could you dig up the specs for the rods you found? I am not going to replicate this, but that information may be handy for someone else.

[datzenmike]

What's the casting number on the top crank's counterweight? L20B usually say U60

[fo0manchu]

datzenmike, it is a u60
Okayfine, i'll try to look up the specs. It has been awhile, i wrote everything down at one point.

[datzenmike]

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.

[fo0manchu]

at least its all cleared.
You sure got a lot of engine cranks there datzenmike!