Gallery>> A Quick Stop @ Os Giken

One of my other ports of call each time I am in Okayama is OS Giken. It's a company I, along with many other enthusiasts around the world, admire for its incredible engineering capabilities. Anyone that is remotely interested or part of the GT-R community will know what great products they create so when I got a call from Yoshi, who takes care of the international side of the business at OS, telling me I should drop by to check out some of their latest creations I instantly took him up on the offer. What follows is a major nerd out, so if you are not into drooling over exquisitely constructed engine parts I suggest you don't scroll down. If you are then prepare for some OS Giken art!

First up the famous OS TC24-B1 twin cam head for the L24 engine which transformed Nissan's straight 6 into a 9,000 rpm race engine capable of developing 330 HP with supporting modifications. This, along with the TC16-MAII engine, is what put OS Giken on the map back in the day.

The cover for the TC24 head with firing order nicely visible in the corner. Only 11 heads were produces and to this day remain the most sought after item by owners of S30s or L-series powered cars.

Something a little more modern. This display engine is fitted with the new OS RB315 stroker kit which brings up the capacity on the RB26 from 2,568 cc to 3,138 cc thanks to a 3 mm increase in stroke and a 0.5 mm increase in bore.

This, like their RB30 kit (86 mm x 86 mm), employs a 26 mm spacer (24 mm for the RB30), added between the head and block. You can see it in the picture above along with the beefy OS Giken quad-plate clutch.

H-section connecting rods as used in the kit. 

Ok this is where people with L-series engines will faint. Finally, OS Giken has decided to do another limited production run of the TC24-B1 head! It's not quite sure how many will be produced but with such high demand anyone wanting to secure one should get in there quick! Anyone recognize the smaller engine on the far right?

The new run of heads will feature some changes like 2-piece bearing caps (right) rather than the one-piece item you can see above on the left. 

Another one for the otaku among us. This is a project the engine-specialist at OS Giken has singlehandedly been working on, which converts this rare Nissan S20's timing, from chain drive to gear drive.

All the cam gears have been meticulously built in house and engineered to give this S20 a very unique character. 

A billet cover had to be precisely machined to clear all of the gears and attach on to the other half. This will completely seal and protect the cogs.

And to go with it, the oil-pump with it's own gears! A work of art to say the least! This should totally change the feel of the KPGC10 Skyline 2000 GT-R the S20 is fitted to, giving it a smoother operation as well as a different sound. I can't even being to imagine what it will be like at 8,000 rpm!

In the transmission department I was shown this close to production version of OS's much awaited Z33/Z34 gearbox kit.

It's currently in the final stages of development and testing but will give owners of highly modified Zs a bullet-proof transmission option with very strong gears and synchros.

And to conclude, OS Giken's wide line-up of limited slip differential has just been joined by a front LSD for the R35 GT-R a part that is selling like hot cakes at the moment!

Hope you enjoyed seeing a slightly more technical look at the JDM tuning world.

Nerd-mode off!

-Dino Dalle Carbonare



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Some more additions to the 'If I won the lottery tomorrow what would I try and buy' list!!!


Love this OG tuning company for their tuning parts


one word: AMAZING!!


more please


This is PORN


Very cool article. Would enjoy more of these perspectives from additional tuners.


ca180det?? OooooO how i wished i had a gt-r to drop all of this os giken stuff into!




please make atleast first photo to a wallpper


Oh my gawd. I want that head so bad.


Rad. I'm feelin this. Love the gear drive cams!


oh. my. god.


if i could fit this... in a 93 cabriolet... hmmm


wow thank you





So hot. Soooo hot. The TC24-B1's like a unicorn. A $25,000 (if you can find one) unicorn. The gear-driven cams on the S20 must sound so fine. If you've never heard what this sounds like, look up "honda vfr gear driven cams" on Youtube.


Nice :P This has to be the coolest thread in a while :) Nice work as usual ;) And the annoying part of me can't help to ask for some wallpapers... Pretty please :D


great report and an inside look to an old famous manufacturer in Japan.


That is just porn for me, thanks guys, you are really the best for bringing this to us.

And if you could, i REALLY want a desktop for the first pic. =)


drool over the L series head!


Absolutely awesome! Dino thank you for this. You made a nerd in me very excited. ;)

I hope OS Giken will amend their past mistake and make more than 13 of these beautiful TC24-B1 engines.

Also, simply WOW for that gear drive modification!

OS Giken shows what the real engineering is all about. Good luck to them!


Incredible! Thanks Dino.


woww.reproduction of the tc24 heads.OMG never thought that this day will come.i wonder just how much the price tag will be since it s a limited edition production.some l28 owners are gona happy


is there any 'engineering masterpiece' like this one done to a Honda??


with that many gears there has GOT to be so much slop due to backlash.

looks sexy!

What's super sexy is the twin turbo RB setup :)


PURE WIN ! i so wish i had the money for one of those tc24 heads :O


Dino you should really take more pictures about things like this!

It´s absolutely porn, loved it sooo much. And that RB30 kit mus be awesooome!


We want more nerd-mode!!!


Great stuff, and a desktop of picture number nine and ten would be awesome.


Dino, honestly this is not an engine... it's a masterpiece ! So awesome it leaves me speechless ! Going over the whole pictures over and over again ! ! ! Just magnificent ! ! !


very cool post! more articles like this on tuners and their products please! e.g. a visit to RAYS Engineering to see proper wheels being made? or Toda or Powercraft or anyone else that makes the finest of tuning parts :)


desktop of picture of numero uno.. thanks!


Isnt that other engine next to the head the twin cam motor that they put in their Bluebird back in the day?


wow, i didn't know they still did heads!! thats amazing.


Wow....these are true pieces of art....


Desktop of number 1 please.


Why cant i have that dohc head for my L24! That cam gear set-up is SICK!


They are some fair sexy pieces of mechanical engineering! And i wondered why i started studying it! It looks like the lads are building a timepiece with all d cogs and gears!!


that is the most beautiful thing ive ever seen. awesome stuff. huge s30 fan btw :)


Dino, honestly this is not an engine... it's a masterpiece ! So awesome it leaves me speechless ! Going over the whole pictures over and over again ! ! ! Just magnificent ! ! !


Absolute masters in refinemnt!


My fave company. Wish I had the cash to get that dohc head.


floodo1 said:

with that many gears there has GOT to be so much slop due to backlash.

looks sexy!

What's super sexy is the twin turbo RB setup :)

acctuualllyyy, that really isnt that many gears compared to the engines iv worked on, and if machined and put together coreectly there should be barely any backlash at all. Im a construction equipment technician, and engines used in that application uuussuually are all gear driven, there are a few exceptions but usually all gear driven. reason being, its much harder to skip a tooth, can support more power, and in my opinion alot easier to work on


I love stuff like this, thanks Dino!

OS Giken is awesome. I can't wait to see some L-Series being modified with the new production of the TC24 heads!


Awesome stuff, thanks!




Super serious car porn.


I've never met until it.

TC24 causes the captive me.

The run is able to experience the feeling that the L series differs entirely.


I'm very glad to see that my recent nerd out on OS Giken engine porn was appreciated. For those wanting


now i regret getting my HKS Step 3 Stroker kit.


Uhhh...why not just use the RB30E block + RB25DE/T or RB26DETT head?Seems like alot of hassle with a spacer.


Time to take out a big loan for one of those TC24-B1's! Z owners have been trying to convince OS Giken to reproduce them for decades. After all, this head came out in 1981!


Its so tiny and cute....looks like a toy


Like the tilt shift lol. Makes all the stuff look tiny.


One of the highlights of the Nostalgic 2 Days was getting close to so many legendary cars of all types


I hope you guys aren't tired of awesome vintage cars quite yet as there is still a lot more to get


more technical stuff please.
and always keep nerd-mode on