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OS Giken twin cam 4 valve head


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Do you guys think this is a head worth having? My contact just told me he found one, brand new, as in never used. It's been sitting in an old Japanese guy's shop in Japan. He is still convincing him to sell the head, which is probably for a ridiculously high price anyway. Ron

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Oh man!!!! I heard of that head. It is mentioned in one of those "How to modify your Datsun" books. It also mentions that those heads went for $12,500 new from the manufacturer. I bet he would probably want alot for it. I have no idea of what kind of power can be had from such a head but I bet it would probably be cheaper to swap in turbo motor or V8. It would also be expensive to get replacement parts for that head.

 

Marcos

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Hi Ron, I have often considered the prospects of that cylinder head in a turbo application. It was not designed for a turbo application, but I think it could be made to work well in that application. Regarding the N/A engine, you can get the same power out of a P90 or an E31 or E88 head with the correct modifications.

The thing about the giken head is the cams, being dual cams makes it easier to advance/ retard each cam to come up with a killer setup. The cross flow design of the head also is desirable, and the placement of the spark plug. The hemi configuration is a far superior design for high hp applications.

The cost, now there is the jest of the matter. I really dont think that you will be able to get that head for a reasonable price. I have often felt the cost was extremly unreasonable. For that kind of money, you can do a custom cylinder head and it would be the same thing there or abouts. Anyway just some of my thoughts maybe you will get lucky, that would be cool if you did. :D

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I would love to have the money to get one of these heads along with the intake and exhaust manifolds. Then start making copies of these parts and selling them to people on this and other forums. I think that this mod alone would pretty much bring a stop to everyone buying RB,SR,2JZ, and many other motors for swap's into Z's. Even though I have RB26DETT.

 

Thanks

JasonRB260ZX

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For a setup that makes 3-6% more power, I would much rather spend money getting a stock head chopped up and re-welded! Coat the piston tops and valves/combustion chamber with some fancy pants ceramic coating.

 

I'd rather spend my money on things like that before going for what is essentially "pimp" value.

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If the price is right and you can afford I say go for it buddy. Having a cross flow twin cam head (4valve) that can breathe will make all the difference. Let us know how it works out and good find. HA! you are making us all jealous.

 

The stock OS Giken head made about 30 more hp than the factory L24 head. So imagine if your motor was worked and was pretty hot or even turbo charged - WOW!

 

Regards - Yasin

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A friend of mine is considering making a 4 valve L-series 6 cylinder head using 3 Nissan 4-cylinder heads, cutting and welding them together to make a DOHC Z head. It would also be belt driven as opposed to chain driven... Neat idea anyway.

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it would be really nice to have a 24valve L28et,

i heard that head is good for 15% power increases on an NA motor stock, imagine when you start pouring boost into it. oh man, maybe he will hook you up for a good price, you never know. i would just get the head as a template......

or i would run just so i could pop my hood at motorsport show after driving 800 hard ones on it, and flip everybody off all at once, with my crossflow turbo headed monster. get it if you see its the right price.

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Guest 240hybrid

I think its already been said, but according to the "How to modify your Nissan/Datsun OHC engine" manual it was listed that a "optional 4 cylinder head" could produce 15-20% increase over the regular heads, dont mistake this percentage to be for the L6. The "optional 6 cylinder heads" only produces a 4-6% increase over the regular heads off of a datsun L6. So depending on the asking price of the heads and the difficulty of installation of them, there isnt a very large bang for your buck/HP increase ratio with these heads. May be worth it to you if you can get them at the right price though. Good luck with you decsion on it.

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Those "4 - 6%" figures that Frank Honsowetz was writing about are in relation to the LY28 Crossflow head, which was a two-valve single cam hemispherical combustion-chambered design. The big advantage of this head was that it allowed reliability at much higher revs than the standard non-crossflow heads, and was well proven in Japanese domestic circuit racing and international rallying. The figures that he quotes are not accurate......

The O.S.Giken TC24-B1 twin cam crossflow head is another matter altogether. The negative comments above ( especially that "pimp value" comment ) are probably based on hearsay rather than first hand experience. This head conversion was very well engineered by a great company, and worked very well indeed. The main purpose of the TC24-B1 was to allow prolonged high rpm use with good breathing. This was achieved, and is well known in Japan amongst enthusiasts of the L-series engine.

In theory, any twin cam four-valve crossflow design is going to be more efficient / desireable than a two valve non crossflow design. The fact that in practice the "normal" L-series engine does so well against such exotic conversions is testament to just how great the "normal" L-series engines are.

 

Alan T.

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whats your first hand experience with the twin cam head? all we know about the twin cam head is based on hearsay and rumors, god everyone knows a twin cam hemispherical head is going to be better for high rpm use-what else is new? over here one of those is so rare that if you ever popped your hood at a show you would have the whole show gawking at your car for hours on end, that is pimp value, because it would be one and a million.

it would be more bragging rights than anything, so if you took offense to my use of the word pimp, you did. cry2.gif

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Len168, I thought it was Mudge who made the "pimp value" remark, not you?

 

Where I come from, the word "pimp" is a pejorative, so in my mind it kind of shows disrespect to what I think is a great piece of engineering from a company that was quite small but very brave when they made it. I feel like I should defend O.S. Giken against this. Someone needs to stick up for them! Those "$12,000" quotes from the Honsowetz book need to be put into perspective for both the Dollar / Yen exchange rate of the mid 1980's and the Japanese economy at that time.

 

My personal experience of this conversion is that I have passengered in a car equipped with one, and was around a group of people in Japan who were using them.

 

When I was living in Japan many years ago, I was involved with a group of people who worked in a tuning shop there. They used two of these heads in "company cars", and one of them was a 3 litre conversion used with a pair of KKK K26 turbos. That was quite an impressive car for 1986. Personally, my taste is more "old school" and I prefer old cars with carburettors - but it was fascinating to see the ingenuity and dedication of the tuners at that time. What they learned then stood them in good stead for when the RB26DETT came out in 1989. It could be argued that Nissan themselves learned a lot from the Japanese street tuning wars of the late 1980's, as they still continue to do.

 

Some years back I was also involved in trying to persuade O.S. Giken to make another small production run of them, which they did not want to do. I don't blame them, as its doubtful that they made any profit at all from the original runs of either the 6 cylinder or 4 cylinder versions. They are doing very well with their current range of Clutches, Flywheels, Gear kits and Pistons. They also developed a 3-litre conversion for the RB26 engine, which I think was very brave. They are a much bigger company now than they were when they designed and developed the TC24-B1 and MA11 heads........

 

Len168, I think you might be interested to see a picture of that twin-turboed TC24 ( if you send me a PM with your e-mail address I can send some to you ). That was one crowded engine bay.

 

I have often "dropped in" to the HybridZ site as a casual visitor, but Ron's original post prompted me to join up as a member. I thought it was a debate that I could contribute to with first-hand knowledge. If that is not welcome then I probably made a mistake by doing so.

 

Sincerely,

Alan T.

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Originally posted by HS30-H:

If that is not welcome then I probably made a mistake by doing so.

Absolutely, your experiences are welcome, things like these are so rare its hard to guess any kind of pricing or find anyone with experience with such a peice.

 

If you took offense to "pimp value" I appologize, the way the word is used has changed through the years, and in England when you "smoke a fag", I can only imagine the difference with "pimp value" aka "bling bling".

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Hi Alan T HS30 - H - I enjoyed reading your recount of being in Japan in the '80s and being around the tuners back then. I think it would have been fascinating to be in Japan during this period as Turbo and EFI technology was growing and the "tuners" were getting a grip on how to make power with these new found break throughs in engine development. I am sure you must have thouroughly enjoyed your stint while over there.

 

I would also greatly appreicate if you could email me some pictures of the OK Giken Twin Turbo set-up - if you don't mind. My email address is slownrusty@yahoo.com

 

Thanks in adavance - Yasin

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Hi Alan, I would also like a picture ofthat setup. If I had the money to do such a setup, I really think I could pull some serious hp out of the engine. I just love a good turbo car, and for that one a tein turbo setup would be really sweet. Then again a setup with a single turbo would be really sweet LOL

mrjeff1@sbcglobal.net

REGARDS: Jeff

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If you don't mind add me to the E-mail list.

 

By the way I understand the term "Pimp." In don't think anyone ment it as a put down but, more as a "WOW" thing. The head is an incredable peice and we have proubly all thought about the what if's of having such an item. I my opinion it should be a museum piece as much as anything else.

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