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Holy balls. looks like someone is actually doing it! DOHC


Mack

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found THIS on zcar.com. Looks like someone is actually making one. kind of pisses me off (in a good way), cause it looks like he stole my idea, lol! They appear to be KA24DE heads. I don't know where he pulled the cams from though! Wish he would give a little more info. It also makes me wish I had sent the KA24DE heads I had off to TBS to get them cut up and milled. Oh well, if it works, then maybe Ill get a little more serious about it! HA ha

 

Mack

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You've got my attention.

 

Things that I would like addresses:

 

1) The internal welding of the water jackets as RacnJasn mentioned?

 

2) Cams - specs and how are they being made, I imagine a custom timing chain will also be required?

 

3) Head bolts - specs?

 

4) Who is making the custom head gasket?

 

5) Valve cover - custom made as well?

 

6) Intake - custom made?

 

7) COST???

 

A professionally ported and polished P90 will bring an extra 30hp to the wheels (approx), so I am intrigued to see the efficiency increase with this DOHC 24V head

 

Yasin

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Guest 73Turbo240z

yea i saw this this morning as well... interesting project indeed, but the head being seperated like that (2 KA heads joined)... i could see a head gasket sealing lightmare occuring even after welding it up then decking it flat... just seems like the welds would be a constant source of woe...

 

if this does work though, i remember reading he posted the CFM it will flow... that said... i'd like to see what a fully reworked p90a flows.. then compare...

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Because the intake ports and exhaust ports are on the same side of the head, the exhaust will heat up the intake charge. A hot intake charge is a big no no.

 

:lol: um.. heh heh.. have you ever looked at a stock Z head? The exhast ports are directly below the intake, on the same side.. seamed to work well enough for the datsun enginiers; They only used the L6 engine for what...15 years?

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:lol: um.. heh heh.. have you ever looked at a stock Z head? The exhast ports are directly below the intake, on the same side.. seamed to work well enough for the datsun enginiers; They only used the L6 engine for what...15 years?
Um, "heh heh", yeah, I think that was the point of his post.

 

Your argument is that because they kept the same crappy design around for 15 years, that it must've been good?

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yeah, the stock datsun head design is absolute garbage. no offense to the engineers, Im sure it was awesome and cost effective 30 years go, but we have better things now. Also, something to consider... I know of a certain KA24DE that has a big friggen turbo on it and about 29lbs of boost thats making 530rwhp. from a 2.4L 4 banger. Now, look at L motors, 2.8L I6, only person I know of running that much boost is JeffP, and hes putting out what, 450rwhp? More displacement and more cylinders, less hp. Yup, that stock non crossflow head is really awesome.

 

as far as the cost thing... maybe 5K may SEEM steep, but think about it. The poeple that are probably going to buy this probably already have a BUILT 3.1L motor, and if they could just bolt on this head? they could keep thier forged rods, they could keep their forged pistons, prepped cranks, everything. From THAT point of view, I can see its worth the money, they wouldn't have to start with a clean slate, you know>?

 

Its piqued my curiosity.

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This idea has already been stated before in this post, but I'll throw it out in a slightly different way...

 

Even if this head yields a very siginificant increase in NA power, say it gets a 50 hp increase, and bumps a NA L engine like mine from 240hp to 290, I still wouldn't be able to race anywhere with this head in a "normal" Z class for autox or road racing. The class that a Z would be relegated to would be the same class that V8's or 2JZ's or RB's or Buick 6's would be in.

 

So basically this is a $5k exercise in keeping the same block that the car came with and getting some power gain. In and of itself there is nothing wrong with that, but still it falls well short of the possibilities of even a very mildly build V8, and will probably weigh more when it is done. It's very cool, very expensive in pure $$$ for hp terms, and kind of pointless except to the purist who doesn't mind the bastardized head.

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Good Point, Jmortensen! I do not know the rules for SCCA racing, and Im sure once you get into the upper eschelons of it, they change dramatically. If one were interested in doing some racing, what would be the rules considering an aftermarket head? its still the same block and what not, just a different head. I wonder what the SBC camaros with dart heads get classed as?

 

 

I personally think it would be good for more than just 50hp. Especially when you start turbocharging. I mean going on the fact that there is a 80rwhp difference between a 2.4L and a 2.8L, just by doing the displacement math you would get 618rwp,. with a 2.8L vs a 2.4L. Thats 168rwhp difference! and thats not even accounting for the higher red line of the L6 vs. the KA, KA made that power without going over 6.75K, me thinks. 96mm stroke, go figure.

 

I just think its funny that all these people say "Oh, If O.S. Giken made the TC24B1, Id buy one today for 10K!" where are they now? lol

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I just think its funny that all these people say "Oh, If O.S. Giken made the TC24B1, Id buy one today for 10K!" where are they now? lol

 

LOL indeed,

Show me a complete TC24-B1 for $10K and I'll buy it.........

 

But that figure was in somebody else's head - and not a quote from OSG.

 

No disrespect intended to Young Frankenstein, but comparing three chopped up KA24 heads and a lot of unanswered questions to a complete TC24-B1 is a 'no contest'.

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well, because I like to argue and stoke the fire around here, and because *I* like the idea, I will just say this, to get CLOSE to the potential, you would need the RB26. and then this thing would still have .5L (30 cu in) on it. If it was on a 3.1L stroker. and with the RB26, you need a LOT of custom stuff. this would sit on stock motor mounts, stock transmission, stock oil pans... all that crap.

 

Granted this would need custom manifolds, but when you're getting into the HP this thing WOULD be capable of, if he can get it to work, you'd be needing custom stuff for the RB anyway, and parts availability is another thing...... this *would* use KA24DE head parts (all available at prettymuch anywhere here stateside) and stock or readily available L series bottom end stuff. its a win win.......

 

Mack

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