the only thing i've seen on this is the 1600 for sale with a KA head on the L series.... is it not a 12-valve? (is it one inlet - two exhaust?) a 16valve head is better yes? to what extent is the KA head better? (how so?)

how about a 20-valve head for a L-series.... anyone
possibilities?

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Gotta spend your $$$ somewhere!

Why on earth would you dismantle that?

Beef, hurry up and do the swap We should catch up and share info before I go overseas.

Dave,
Touche!


deva,

The "KA head on the L series" is Zac's car. His engine is the inspiration for mine (thanks Zac!). Zac used the KA24E head, which is a SOHC 12 valve setup. The KA24E head has a large combustion chamber and no squish bands (good for turbo, as it lower the CR??).

There is also the KA24DE head. This was only fitted to the U13, FWD bluebird of the mid-90's in Oz. It is a twin cam, 16 valve head. It has a smaller combustion chamber and squish bands. The combustion chamber looks just like that of an SR20. This is the head I was referring to.

Why do I think it's better than the other heads for the L?

* Very good combustion chamber design, with a chamber volume suited for high compression atmo motors (approx 10.5:1 say).
* B-I-G valves. 36.6mm on the inlet. King Kong would feel inadequate next to those babies.
* Direct valve actuation (no rockers).
* Solid lifters of shim-over-bucket design.
* Narrow valve angle (narrower than all other Nissan 4s).
* Straight ports.

Problems?

* Detail of inlet ports. Port tapers the wrong way!! Would need porting to correct.
* "Twin run" timing chain. There are actually two timing chains used on this head, which I think was used for clearance (to water pump) reasons. First chain goes from crank to an idler shaft. Second chain goes from idler shaft to cams.
* Difficult to get performance parts for. Still easier than OS Giken or LZ tho...

20 valves? Sheesh! You've got the option of 8, 12 or 16 valves (what a testament to Nissan interchangeability) - but it's still not enough! Seriously though, I think the 20v 4AGEs are probably proof of 20v's not really working in practice. Also that some F1's used to be 5v per cyl, but they have since reverted back to 4v/cyl.


Zac,

I'd like to catch up with you. Offer still stands for you to see what I'm up to. Lots more trick stuff than the heads too!!


All,

I can post some pics of how little I've done if you like. Just gimme a little bit of time.

Cheers,

Beef.

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KA24DE uses the same head gasket as KA24E?

And I assume you are onto this project beef?

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nope.

ok, I'll scrap that idea then.

Anyone lined up a KA24DE head gasket over an L20b?

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Mad, the important bits line up (ie bores, head bolts).

Head gaskets are different. The "E" uses a normal, one-piece gasket. The "DE" uses a two-piece gasket.

Why? Because you need to remove the top timing cover (bolts to front of head), to access the idler shaft.

Yes, I'm onto it. I'm also onto a lot of other projects... It's gonna be a while. Somehow nothing's finished yet either... Where does all the time go?

I have put the head on the block (I have most of the bits required now), and spent a while checking how the galleries line up, etc. Everything lines up beautifully, except one at the back of the head. This is just like the "E" head, and Zac detailed this on his webpage.

Biggest problem is the timing chain. Everything else looks sweet.

Beef.

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Now that I think about it, the timing covers don't line up either. Need to chop off the top of the L's cover, and weld/bolt on a new top to it.

(Zac, I double-checked that later on, and you were right).

The main thing is that all the "business end" is perfect. Good as you could ever hope for.

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once you get it done....... do a full article on it ? and then.. make me one

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Gotta spend your $$$ somewhere!

Pics...

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Beef,

What sort of power are you hoping to get once it is running ?
are you keeping it NA or FI ?

Cant wait to see the end results.

_________________
1975 P610/180B SSS ex PRC3 Rally car (parts car)
1974 P610/180B SSS (parts car)
1972 P510/1600 Currently sitting untouched
1977 P610/180B Wagon Daily Driver

FWIW. saw this post on a US forum.

I have built many of these ka/l/z hybrids. Sohc and dohc 2.0-2.5l and next season dropping down under 2.0. These are unlimited formula replicas, only legal in a few forms of racing here in the US.

the basics

Many combinations are available utilizing l/z/ka series parts, in both FWD/RWD form. I prefer full custom rotating assembly components but as is well known, lots of compatibility here using oem parts. I recommend not using l series block with ka head or you will have a small leak issue dont try it. Stout medium deck ht z blocks are of choice. ka24e/ka24de heads from both rwd/fwd can but used in either platform (except for dual cam rwd heads in fwd).

Sohc ka head swap to any z series 4cyl block is no brainer, you even get to keep the stout timing/adjustment setup. Combustion chamber volume is large (65cc) in the sohc head, so custom piston or chamber volumes is necessary for high compression ratio. Front cover/deck passages/headbolt length is directly compatible. I have built many of these sohc, it is a great platform. I offer a few custom valvetrain parts for these engines online.

Dohc ka is similar in a few ways. Main deck layout of all ka20,24 is same so no issue here. Front timing cover modifications depend on cylinder head version, rwd 240sx model have extended front upper cover for the distributor drive so they are more difficult to mate to standard sohc shape cover. Rwd frontier ka24de and fwd altima ka24de do not have the distributor drive in this location so the cover is easier to fit. Some modification is required. Lower timing chain setup must be full custom, Ive made up a few of these sets for some in the race community as well as my own engines. Custom length chain/custom lower gear/and custom guides are required. Single lower chain is only option, I recommend a very high quality race chain for this, I use Renold race roller 06H on all of mine.

Always run external oil pump system on any performance build of the nature, the stock system is not even close to adequate. Dry sump is the option, but if the car has lots of sump room a nice wet sump with external scavenge can do the trick cheaply.

Also, never run bore less than 88mm with 2.4l head

I work with these a lot and have a lot of custom parts built in house, im slowly trickling some products online.

My latest build for the datsun i just got is a 2140cc dual cam. Full custom rotating assembly designed to be as low friction as possible. I have more time into the shortblock than i would care to mention. Cylinder head is a modified fwd ka24de casting with 35cc custom chambers, with custom intake/exhaust manifolds. I built another dual cam 2200 a couple years ago, and sohc ka hybrid has been around for years, its been done.

-deviousKA

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"R.I.P. Baz. 29 April 2022. Thank you for all your contributions to the Datsun community over the years. You will be missed." - OZDAT

Thanks Baz, never heard of that bloke before. Is there a link to his website? I'd like to check out his drivetrain parts

I wonder what he means by a small leak issue?

Datsss73,

I'm keeping it atmo. I have more than enough to work on, without having to get my head around forced induction.

How much power? I'm not going to put super-wild cams in so it won't be spectacular (I'd like some driveability, thanks). I also plan on quad throttles + EFI. Street / club-level motorsport. From looking at 4cyl motors with similar bore, stroke and head design, I would think over 200HP at the flywheel isn't too far off the mark. Kinda hard to say, tho. We shall see.


Baz,

Interesting. Cheers for the info. I'd seen (but hadn't contacted) deviousKA on the nico forums years ago when first looking into this setup, but it hadn't been done then. I think. Might have to contact him sometime.

Strange comment about the leak problem with L blocks. I would have thought Zac's disproven that one. Can't imagine why it would be different than a Z block??

FWIW, the only DE head we can get in Oz, is the U13 head. It is of the FWD type that deviousKA mentions. His comments about the lack of distributor drive at the front are correct. I had noticed the US RWD heads were different. I kept looking at the photos thinking "why doesn't that look the same..?"

Also interesting that he only uses top-spec chain. I imagine that's because the DE head's idler shaft only wants a simplex bottom chain. I plan on using a custom duplex setup.

"Lower timing chain must be full custom" - yep. That's the biggun'. The sprocket ratios don't work. IIRC, the L20B crank sprocket is 20t, but the DE head forces you to use an 18t crank sprocket. The size of the crank noses are different for the KA, so parts aren't interchangeable. Tensioner isn't even close to working. All fixable, tho.

You will have to watch bore size. I haven't worked out the minimum bore yet. I would imagine you could use a smaller bore (why?), if you notched the top.

Cheers,

Beef.

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