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DOHC 'OS Giken'


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I came across this on youtube and have since tried to get more info on it. It seems more info is available for the L24 and L28 than the DOHC L-series produced by OS Giken and being sold for $30,000 USD(that's if they could get enough orders). Anyway here's the info I've gathered so far. I'm trying to gather more info on the TC-16 MA2 setup for the Bluebird/510/1600.



Taken from youtube user "PixeInem"


The L-series Nissan engine made it's first appereance in 1967. It was widely used in racing due to it's so called 'bullet proof' bottom end. The main limitation was the head design, tuners began to search for ways to improve the performance.

In 1973 a Japanese engineer named Osamu Okazaki designed a whole new cilinderhead for the L-series engine. The design used 4 valves per cilinder and a narrow included valveangle of 20 degrees. Combined with racing cams, racing pistons and DCOE Webers the 1888 cc engine outputed 232p PS and 203 Nm of torque.

The actual design was build via wooden negatives which were made of cherry wood. The particular head 'TC-16 MA2' had a limited production and is still sought after by fans and lovers.

One of the chief engineers at OS Giken joined the company in 1994 and learned allot about their twin cam head designes. He also noticed that they still had the parts in the warehouse. He asked permission for building one more racing engine.

The movie shows the start up of this particular engine. It is still used for racing. They later shifted the rev limit from 9000 to 10500 rpm. Torque was still high at this large velocity's.

OS GIKEN is known for their sequential gearboxes, Limited slip differentials and clutches. A lot of people don't know but they had a big influence in racing history.

Here is the blog post excerpt from www.japanesenostalgiccar.com:



reading the comments section here is a reply from user "OS Giken"

OS Giken Says:

November 17th, 2009 at 5:03 pmThanks for the superb article. We were very fortunate to be able to display such a wonderful piece of Datsun history at our booth; to our knowledge it was the first time a TC-24 head was displayed outside of Japan. If anyone is serious about acquiring one of the proposed new units, OS Japan is willing to manufacture them if enough people are ready to put down a deposit. The manufacturing chief mentioned that they need about 25 people lined up to get the ball rolling, and there are already several people ready to pull the trigger on it! At approximately $30-35K it’s definitely not for the meek.


Regarding the original production numbers, only 9 of the TC-24′s were produced, including the one displayed at SEMA. There were over 20 of the TC-16 heads made, though.



Again more info on the L-24/28 taken from Speedhunters:





Anyone with more info, post up what you know.



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That thing sounds amazing.

These heads should bolt-on an L20 block? That would be cool.



the head pictured below will fit an L20A block not an L20B block


there was an L6 2.0L in Japan for some of the skylines and Z's

thats why the L4 L20 gets the "B"

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Wait, so what you're tell me is...


I can spend ~$35k for the head, plus ~$10k for a bottom end that can take advantage of the head, and wind up with about 230hp/200ftlbs?!


Well crap! Why didn't someone say so. Idiots with their KA, SR, VG, VQ, <insert motor here> motors for under $5k doing more than that. What are they thinking?!

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The M104 head bolts on. You have to pull the centering pins out of the L28 block and bore the thing to 88mm to have any dreams of clearing the valves, but it bolts up. The oil galleys are directly accessible from the rear of the head and the water flow is kindasortaclose enough that you could make it work with devcon in the m104 water jacket. You'll need to turn the snout of the L28 crank to SBC snout dimensions so the M104 bottom crank pully will fit (unless you modify the VVT and the exhaust pully or have a custom exhaust cam hardfaced to remove the VVT and then run two separate L28 timing chains)... and you're good to go!



Or... you can spend 120bucks, get a W140 S class entire 3.2L M104 out of a u-pull it, discover that in 220k miles, the rod and main bearings still are at .0015 clearance (max .003) and the pistons are at .002, get rings and bearings, and for under 500 bucks have a motor that will happily live at 500hp....



I did the latter.

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the head pictured below will fit an L20A block not an L20B block


there was an L6 2.0L in Japan for some of the skylines and Z's

thats why the L4 L20 gets the "B"


Don't they have one for an L16?


Anyways, would be f*ing awesome to see one on a Hakosuka GTR. :)

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i dont think the point of the OS giken head is power, or being better than x


just to show what they can do when they try. imagine being able to cast and machine your own cylinder heads to do whatever you want with whichever engine you please


good for the small number of people who could and would afford it


either way its cool shit :D

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Makes me wonder. With 30k do you get an intake, head, special timing assembly, headers, and all that crap? Like carbs, hoses, blah blah? If its just a head. dang... That is expensive!

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They also had an L16 head... or a KA24 head bolts on to an L series block... that seems the logical move there.


Remember Nissan also made the LZ heads for the 4 cyl. They're really easy to distinguish from the OSG heads since OSG had the exhaust on the left and nissan put theirs on the right (IIRC).



And I believe the 30k price tag gets you a whole engine package to go on your L24: Head, timing set, header, pistons, intake, etc. I do believe that sourcing carbs was up to you though.

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Well from what it sounds like, it is definitely possible but the costs would certainly outweigh the benefits. Especially a broke dude like me with no resources or machining tools.


I certainly like the idea of having something no one else has though especially using an L16 block.

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Yeah It's called a KA24. Cheap, 800cc's more displacement. I think doing something just because nobody else has it is a little pointless, but you'd want the full counter L20 motor and turn the bitch TIGHT to make use of the KA head. Fully ported that thing does pretty good for itself and has a decent valve train. If you could make an L20 botom end live at 10k, that would be a sweet little motor.

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