Japanese stock engine

[christ0ph]

Hi all.

I'm still in the process of looking for a Z to buy. I found this 73' 240z with the Japanese 2.0 dohc engine. Excuse my ignorance but is this a good find? The first time I test drove it I fell in love with it. The car is in decent condition. There's a little bit of rust right above the hatch...and other than that I couldn't find anythign else. Now, both door handles are broken and the gauges don't light up inside. I know all of this is vague but I can't think of anymore. I'd like your guys opinions on what I should do, and if you think the repairs for this car will cost a lot? The price that the guy is asking is $1695 usd. If you need more information, reply and I'll respond with the best of my ability. I look foward to your replies. Thanks.

Chris

[HS30-H]

Originally posted by christ0ph

I found this 73' 240z with the Japanese 2.0 dohc engine. Excuse my ignorance but is this a good find? Chris

Hi Chris,

Unless you have accidentally hit the jackpot and found a real Fairlady Z432 ( PS30 ), I don't think that the engine in the car will be a DOHC .

Its much more likely to be an L20 - essentially the same as the L24 but with a smaller capacity.

You didn't mention that the car was RHD, so I would assume that you are talking about a US-market "240Z" that has had an L20 engine transplanted into it. That would not be considered an upgrade by most people.

However, if it is in fact an RHD car you may well be looking at a privately-imported Japanese-market car. Many of these were brought home from Japan by American servicemen ( I've got one of these too ).

Check out the VIN number to make sure ( best place to look to make 100% sure is on the firewall metal above the brake booster - and you may have to push away some tubes and wires to see it clearly ).

We have discussed similar subjects here in the past - so use the SEARCH function ( try words like "Fairlady" or "S30" or "VIN" and you should find some interesting info ). Good luck.

Alan T.

( ps - If it says "PS30" on the VIN code then all your Christmases will have come at once ).

[christ0ph]

Hi there Alan.

I appreciate the reply. Sadly you are correct, not the jdm ps30. I was wondering how do you tell the PS30's engine apart from the regular 2.0... and where did the 2.0 come from...? Has me mystified at the moment but I'll continue to read up on it. Thanks once again.

Chris

[Ben]

The 'regular' 2.0L is just an 'L' block with a (very) small bore & stroke. Externally identical to the other 6-cylinder engines of the same family.

The S20 on the other hand - twin-cam, triple mikuni's, factory extractors - I wish someone would mistake one for an L20 & sell it to me cheap.... :love:

[Gav240z]

Gotta love the uniqueness of it all.

[2ManyZs]

What I would really like to see is someone that would just make the head to put on an L-28 block, now that would sell.....

Shame no one has ever just done the top end of that engine in the aftermarket.:disappoin

You would think with all the millions of dollars spent developing parts for the aftermarket, someone, somewhere would have had it done by now...

[HS30-H]

O.S.GIKEN of Japan made the TC24-B1 twin-cam 24-valve head conversion kit for the L-series back in the late Seventies.

This was quite a comprehensive kit, rather than just a bolt-on accessory. New pistons were required, and machine work on the front of the block to mount the new cam drive chain system. The whole front timing cover was different too.

It actually worked very well - but its complexity ( as well as the fine engineering quality ) made it rather expensive..............

Alan T.

[2ManyZs]

Back in the late 70's I would imagine it would have been quite expensive to do.

With today's billet aluminum heads and cams, belt driven cams, and the wide array of pistons available it's kinda sad no one will give it another shot at a conversion kit. It could probably done quite easily and fairly priced.

Especially when you see how many millions of dollars that must going into R&D and manufacturing of all the aftermarket pieces for the 350Z already....not to mention all the other cars on the market.

[christ0ph]

Hey guys thanks for the pics, they really helped me out. And Alan, I did as you said and looked up on the L20... mostly reading your old posts...how can one man know so much?? Anyway, anyone know what the L20 is pushing bhp wise?

[Ben]

I'd say that it'd be a shade over 120HP with twin carbs or the EFI & ~110 for the single carb version. BUT, I don't have any SDS books handy, so I can't be sure.

It's no beast anyway :classic:

[Gav240z]

Hey Alan,

Is the kit very hard to get a hold of? No doubt it's expensive.

I think you've mentioned this before but the L Series engine shares no similarities with the S20 does it??? What i mean is you can't just slap the twin cam head onto a L engine???

Chris! Alan is our little Guru or bible or database. We just love him :classic: .

I hope to know as much as he does one day :classic: .

[Gav240z]

Before I leave it at that for others reading I think I should also mention that the S20 had different engine mounts is this correct??

Also are the gearboxes compatible?

And is the weight of the engine any different? more less <>.

THanks.

[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.