Japanese stock engine

[HS30-H]

Hi Gav,

O.S. GIKEN don't make the TC24 head conversion any more ( they have not made any for over 20 years now ). I talked to them about making a short run whilst I was living in Japan, but even then they were not interested. They are still a small company ( although bigger than when they made the TC24 ) and they are very busy with making new products, like their gear kits and clutches for domestic high-performance cars. They don't really tend to wallow in nostalgia, but a few years back they launched some "O.S. CLASSIC" parts, such as piston kits and the like.

Would be nice if they did do another short run of the TC24 at some point. They would be expensive, but worth every penny in my opinion. I think they were very brave to make them in the first place, and some of the negatively-biased comments from people who have never even seen one are a bit annoying. Hats off to Giken, I say.

Original examples that are still useable are very thin on the ground in Japan. They tend to be the kind of thing that the older enthusiasts have stashed away and won't sell for any price. Remember that many of these head conversions were destroyed in the silly years of Japanese street-racing, back in the mid to late Eighties period. Big blow ups at high speed took their toll on the TC24's and LY engines that made it out onto the streets.

The S20 twin-cam is a different kettle of fish altogether. It shares no mechanical components with the L-series engines. I've read on other sites that the S20 head can be put on an L-series block - which is total nonsense. They must be getting mixed up with the TC24 head or the SOHC "LY" head ( often called the "Crossflow" ).

The S20 was derived from the Prince GR8 racing engine ( which had twin distributors running off the ends of the camshafts ) and Prince / Nissan de-tuned it for street use in the PGC10 Skyline GT-R of 1968/9. When the Fairlady Z432 was launched in late 1969, Nissan's press releases called it a "Fairlady Z with a GT-R engine".

The front crossmember of the 432 is different to the normal L-series engined version ( I'm having an L-series version modified into a copy of the S20 version for my 432R replica project ). However, this is because the engine mounts are further back on the S20 block - rather than being at a different angle side to side. The S20 mates with all the same transmissions as the L-series engines ( the 432 and 432-R came first with the FS5C71-A 5-speed, and then the FS5C71-B 5-speed ). The "LY" Crossflow used different engine mounts and bellhousing to the normal L-series, as the block was angled differently.

Weight of the S20 was very similar to the L-series in 2-litre form. Just a few kilos difference ( S20 was slightly heavier - not surprisingly considering its extra complexity ).

The S20 engine is an automotive icon in Japan. Its kind of annoying that its been almost written-off as a dud ( or damned with faint praise ) by automotive journalists outside Japan and "experts" who have never even clapped eyes on one. Everybody seems to just look at its capacity and imagine that it can't be any good - totally ignoring that the way it makes its power, and the way this is linked to its close-ratio five speed and LSD-equipped 4.44 diff. in the light Z body is what makes it so much fun to drive.

Same goes for the L20 engine, which is what christ0ph originally asked about. These engines are not all that bad at all ( especially if attached to a nice five-speed and a 3.9 ratio diff. ) and are really smooth and revvy. The problem is that if its been put into a US-spec car ( four-speed and corresponding diff. ratio ) it will feel like a bit of a slug. This is why it will be considered a downgrade.

Alan T.

( ps. - Gav, I only know about what I'm interested in - which is a fairly narrow area. I'm no self-appointed 'guru' or anything. ).

[christ0ph]

Alan:

The depth of your knowledge owns me.

To everybody else:

I've been looking online for different engines...trying to plan out what I have intended for my future car...wishful thinking..? Anyway I've been looking at rb20's, rb25's (rb26's are a tad too expensive for me). sr20's are also a viable alternative (although 4-bangers sound like poo). The 280zxt block also looks promising to me...but I have been unable to locate a site that sells an this engine. Perhaps I'll have to go out to a junkyard and look for it. My question is, what am I looking at for the cost of the zxt block? Any other helpful suggestions? I apologize for being such a newb on the forum. Thanks for understanding guys.