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PostPosted: Thu Nov 03, 2011 1:54 pm 
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Location: Zombie-free unfluoridated town in QLD
Im interested to see why some U20 engines are making 234-250hp ate
while some of the best L series only make 200-220hp?
I know the u20 is rare and heavy but some fairlady peeps are claiming
250hp in full race versions. Do any L20B make those figures?

u20 where factory with 46mm inlet valves!!!!

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The Works Datsun Sports 2000 race car is the original David Mingay modified Prod Sports racer, I have owned it for a while, and regularly still compete in a lot of historic meetings.
Set a new Group O record at 2007 Australian hill climb champs, and a few first outrights and podium places at a lot of circuit meetings and a few fastes lap records in some races.
Incredible but true, It still runs original U20 motor, 234hp at 7500 and 181ft/;b at 5500
It is fitted with parts from Datsun competiton parts catalogues. want to know more, just askme
Check out Group S Racing websites for Morgan Park 2007 and 2008 race reports.


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PostPosted: Thu Nov 03, 2011 7:23 pm 
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If you saw the head on a U20 you'd undertand.


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PostPosted: Thu Nov 03, 2011 9:31 pm 
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I'd guess that the head benefitted from being designed purely for a sports car. The engineers didn't have to compromise like they did with the L-series, which was used in everything from sports cars, to passenger cars, and even commercial vehicles.

150hp from the factory, they must have been doing something right :thumbsup: .

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PostPosted: Thu Nov 03, 2011 11:27 pm 
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Absolutely a golden time for nissan engineers, probably the best time ever for Nissan
engineering input and freedom. Seems the takeover of Prince motors made them more
conservative or cost cutting in the design department compared to toyota but in the
end Nissan is second to none with its few engines it kept using. Just admiring recently
the H20 also which Lou M got 117kws from and to think a H25 93mm stroke crank was
also available for a torquer!

Could a U20 head fit an L20B?

Datsun/Nissan Racing should have revamped the U20 to use at Bathurst
with EFI, turbo and intercooled George Fury bluebird would be even faster!


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PostPosted: Fri Nov 04, 2011 6:42 am 
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im not too familiar with the u20 heads but how would the performance compare to a L20b with a twin cam LZ cylinder head?

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PostPosted: Fri Nov 04, 2011 10:24 am 
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Are the U20's cast iron head or aluminium?

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PostPosted: Fri Nov 04, 2011 11:07 am 
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Aluminium - they are very similar in a lot of ways to an L-series head. They use the same valve train, non crossflow, but rather than one long timing chain, they use a jackshaft setup - you can see the progression from the pushrod R16 to the OHC U20, Nissan just replaced the cam in the R16 with a jackshaft and moved the cam upstairs into the head. So crank drives jackshaft, then jackshaft drives cam.

Image

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1971 P510
1972 180B SSS
1965 SP310 Fairlady
1966 SP311 Fairlady


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PostPosted: Fri Nov 04, 2011 11:22 am 
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And I very much doubt you'd get one to fit on an L20 - I'll have a look tonight, but almost certain it won't work.

I'd say the LZ twincam head would way outperform the U20, but then again it was a "race only" part compared to the production-based U20.

svd001 wrote:
If you saw the head on a U20 you'd undertand.


:hail:

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1972 180B SSS
1965 SP310 Fairlady
1966 SP311 Fairlady


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PostPosted: Fri Nov 04, 2011 11:41 am 
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My friend's Roadster has a U20 and makes about 180hp. I don't know exactly what has been done but I know it has at the very least been bored, stroked and balanced, and still runs the original twin Solexs. It's his daily driver.

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PostPosted: Fri Nov 04, 2011 1:22 pm 
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They are an absolute gun. 243hp at 7500rpm is massive.
191lbs!!!! more than most 3 litres!
What freaks me is that even Toyota 2/3Tc series have
amazing aftermarket parts and if this engine in wealthy
or passionate hands had things like titanium valves, rods,
camshaft (yes they are available!), and other special
componentry to match it would be even more of a monster.
To hear that a 60s Nissan engine mass produced can
make around 250hp NA from 8 valves is absolutely mad.

Can only imagine an early 60s sylvia with 2.4 litre U20 w/ latest staged efi,
cross over ford XF like custom manifolding, latest compound turbo setup
and still looking as olskool as possible over any modern complicated donk!.
Even the 93mm stroke H25 crank is a bolt in affair!


Last edited by d on Fri Dec 02, 2011 11:53 pm, edited 1 time in total.

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PostPosted: Fri Nov 04, 2011 9:33 pm 
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if u get an l20b with a z24 crank, l18 conrods, steel head gasket, z20 head, t28 bb turbo, 3" exhaust, good ecu, big fuel pump, 500cc injectors etcetcetc u could make big power from an l20b

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PostPosted: Sat Nov 05, 2011 1:50 pm 
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But it still wouldnt come close to a U20 mildly worked
or a U20 with a H25 93mm stroke crank and 92mm bores
for 2.5 litres of pure roar and gearbox munching.


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PostPosted: Sat Nov 05, 2011 3:23 pm 
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Checked last night - An R16 (and therefore a U20 as well) is about 1/3 of a cylinder longer overall than an L-series when comparing bore spacing. No chance of them interchanging.

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1965 SP310 Fairlady
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PostPosted: Sun Nov 06, 2011 3:21 pm 
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Darn it, Nissan should have continued with the Better Prince technology.
If it wasnt for Prince they wouldnt be who they are today thanks to the GTR department.

Another donk that interested me is the GR11 or whatever Prince Cedric or other cruiser beast used.
That would have been a beast in an early Fairlady.


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PostPosted: Sun Nov 06, 2011 6:54 pm 
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mine is putting out 243 at 7500 and 191 ft lb at 5500 It poos over a L20B
stock block and head, steel internals, slight mods to a billet cam, 9 you cant get the lift and duration from grinding a stock cam) the head is so close to a L series FIA head from a porting perspective it is not funny.
my thing passes Shelby Mustangs, De Tomaso Panteras, Porsche 2.7 RS & 3.0 Carreras, and 260z's all in race spec, at Phillip Island 2011, in 2010 i was in the pre 1970's class with mistangs, Corvette 7 litre, Morgan v8s, and won all four races.
At bathurst, best was a fifth o/r behind four porsches in 2010

This Datusun 2000, is acknowledged as the worlds longest racing, most succesfull, and most winning Datsun Sports 2000, currently today. it is quick, it uses all parts available in the day from the Nissan competition parts catalogues, it isnt a highly modified all out thing, just a basic close to stock Datsun Sports 2000, just well built and well looked after.

My other THING, is a FJ24 equipped Datsun 120Y factory built rally car, for a little sheep farmer in Talmalmo, back in the 1980's, IT is developing 320hp at 8500, on twin side draft carbies, all atmo, and all standard as it came from Nissan, save for fresh steel and new internals
It's off to the Alpine rally in a couple of weeks time!

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