[PS30-SB]

Thought I'd make a thread relating to an ongoing long-term project of mine. I'm building an as-close-as-possible replica of a 'PS30-SB' Nissan Fairlady Z432-R.

A little background data: The Fairlady Z432-R was the super lightweight GT race homologation version of the Fairlady Z432, built in small numbers expressly to legalise the model for use in Japanese domestic GT racing. The Fairlady Z432 itself was a limited edition homologation model ( less than 450 cars built ) and at the time of its launch in October 1969 it was the halo model in the new S30-series Z range. The Fairlady Z432 and Fairlady Z432-R combined the new S30-series Z body with the S20 twin cam engine of the PGC10 Skyline GT-R, which had been launched 8 months previously in February 1969. So, the 432 and 432-R were the second models to receive the blue-blooded, race engine-derived S20 twin cam engine. The KPGC10 would not debut for another 12 months, in October 1970...

Nissan advertised the PGC10 Skyline GT-R as a 'Wolf in sheep's clothing'. If anything, the 432 and 432-R were more like a 'Wolf in wolf's clothing'...

The new 'PS30' Fairlady Z432 centre stage, on a revolving turntable, at the 1969 Tokyo Motor Show:





The heart of the matter: The 1989cc 24-valve twin cam S20 engine:



'432' = 4 valves, 3 carburettors, 2 camshafts:











JAF homologation papers for the 'PS30' Fairlady Z432:

 

[davew]

Can't wait!!

 

[PS30-SB]

So, having a base car to build around ( more on that later ) I had to find an engine. No point in building a 432-R replica unless it had a proper S20 twin cam engine, but they are not exactly all that easy to find...

Adding to the difficulty, the 432 / 432-R version of Nissan's S20 engine was one of the rarest variants. In order to fit the S20 into the S30-series Z body, Nissan re-engineered it with a rear sump location, re-located oil pump pickup and re-located dipstick, amongst other small differences. With something like five times as many front-sump GT-R variant S20 engines having been made as the rear-sump 432 / 432-R variant, it was going to be much more difficult to find the correct type of engine. It was looking as though I'd have to buy a GT-R type S20 and then convert it.

Trouble is, there are not all that many S20 engines of any type that come up for grabs. If anyone has a spare, they are usually hanging onto it for their own use. On the rare occasions I'd seen them come up for sale in Japan they were changing hands at pretty frightening prices. This was going to be difficult. At the time I started looking - a good few years ago now - it seemed likely that there were no S20 engines outside Japan, so I concentrated my search in Japan. It took ages.

Eventually - through a friend of a friend - I was given the chance to buy a complete and running engine. Only trouble was, at that point it was being borrowed by another friend ( installed in a PGC10 race car ) whilst his original engine was being rebuilt. I would have to wait. And wait! To cut a long story short I did at long last get that engine - but it was by then re-installed in the KPGC10 that it originally belonged to. Actually, that's another story...

In the meantime, the planets all lined up and something wonderful happened. A correct - early - 432-type S20 engine, virtually complete, landed in my lap. It was in the hands of a Z specialist in Kent, and had arrived some years earlier in a consignment of used parts that they had imported from Australia. The story was that a used Japanese engine supplier / breaker in Perth, Western Australia had bought the S20 engine from one of his suppliers in Japan as a kind of curiosity, and had done nothing with it. It languished for some time in Perth, and was then brought to the UK. Amazing! I negotiated to buy it, and went to collect it.

The engine had obviously been removed from a crashed car in Japan, probably some time time in the late 1970s. The breakers had gas-axed the exhaust pipe and cut the wiring loom around the bellhousing area, but had - very helpfully - left all the ancillaries and some very useful Z432-specific parts on the engine. This would save me a lot of time and effort. There was some crash damage evident: The water pump body had been crunched, the distributor was bent and mangled and the outer part of the carburettor airbox was missing whilst the back plate was mangled. The sump was bashed and dented - probably by being moved from place to place - but repairable. But no big problems, really. Except that it was something of an unknown quantity. It appeared to be seized...

So here she was, as found:



Then, back home in the garage:

 

[Mookistar]

I have waited so long for you to start a project thread. Your attention to detail on the forum is second to none and I cannot wait to see what one of your cars looks like from the ground up!

Subscribed!

Mike

 

[PS30-SB]

One particular aspect to all this was going to be a challenge. There just isn't any technical data for the S20 written in the English language - let alone all the tricks and tips that are so useful - so I was going to be on my own to a certain extent. I have a lot of Japanese literature and manuals, and they would be useful, but I still didn't even know the questions let alone have their answers.

Luckily, all the pictures are in 'English':

 

[Rain]

Awesome Alan, cant wait to see how this progresses

 

[PS30-SB]

For the period ( this engine was first sold to the general public in February 1969, remember ) the S20 was quite a complex design, and especially so for a mainstream Japanese manufacturer. If this engine had been fitted in a European-designed model of the same period it would be held in great esteem by the European and American press. As it is, they've hardly heard of it.

The S20 was derived from the Prince GR8 race engine, which - when Prince was forcibly merged with Nissan by the Japanese government in 1966 - became the 'NISSAN' GR8. The GR8 was very successful in Japanese domestic sportscar racing in period, fitted to the Prince R380, Prince R380A-I, Nissan R380A-II and Nissan R380-III.

In December 2013 Nissan ran the original Prince R380 at the NISMO Festival, fresh from a complete refurb by NISMO staff. I was privileged to help with the resto of the car, sourcing and supplying some of the English-made race parts ( magnesium rear uprights, Girling brake calipers, master cylinders and slave cylinders etc ) as used on a typical 1960s race car, and attended the Festival to see the car run.

Here's the R380 during restoration at NISMO:


And the GR8 engine:


Here's the car at the NISMO Festival ( Kazuyoshi Hoshino driving ):

 

[PS30-SB]

One of the complexities ( for a 1960s production engine at least... ) is the fact that the main bearing caps for the crankshaft are cross-bolted. This was an attempt to strengthen the bottom end and ensure that it stayed within tolerance during high RPM use ( crank 'whip' on a long 6-cyl crank being a bit of a problem at the time ). There are sized shim washers that are inserted between the mains caps and the inner skirt of the block, which the cross-bolts go through. The S20 engines were effectively 'blueprinted' at manufacture. There are sizing and grading marks everywhere on it.

A picture or two hopefully saves any more poor explanation from me:

 

[PS30-SB]

Alternator pulley bent and cracked ( more evidence of accident damage? ), crank pulley rubber decayed and delaminated, nice ( factory ) lockwiring on the fan pulley bolts ( probably never been off ):



More 432-specific S20 parts: This style of crankcase breather was unique to the 432 and 432-R, as were the original triple Mikuni N40PHH-A24 carbs:

 

[PS30-SB]

The original exhaust manifold was still intact and - despite the surface rust - perfectly serviceable. They were made from a grade of stainless steel, and tended to crack in service. This one is destined to become a piece of garage wall 'art' though, as I have bigger ideas.

Good job the cam cover is present and intact. These change hands for silly money in Japan - largely because they too make good garage wall 'art'. Finish is 'crackle' black on this particular one, and I think its 'factory' finish. Most of the cars shown to the press and at the Tokyo Motor Show ( see first post ) had a mid grey 'crackle' finish, but some of the Works race cars had black painted covers that were Magnesium castings. This one is ( normal ) die-cast Aluminium, but painted black. Curious. It has been suggested that the car this engine came from might have been a 432-R. More on that thought later...

Cylinder head is a ( correct for an early 432 / 432-R ) 'K3' casting. Most of the PGC10s had 'K2' castings. There are slight differences in combustion chamber shape, and differences in the internal cooling passages. Luckily the engine was 'dry' stored, with no coolant inside. Very little corrosion in the head, which is a relief:

 

[PS30-SB]

I was still worried about the fact that the engine did not want to turn over. I wasn't going to force it as I didn't want to break anything. In the end I found that the distributor was so badly bent that it was stopping the crank from turning... Phew! I'd need a new / replacement dizzy, but now the engine turned quite freely with the plugs out. Now I could carry on stripping down.

S20 engine blocks have a casting date code on them. This one was cast in February 1969, a full EIGHT months before the 432 / 432-R were released to the general public. The story is that the foundry would have cast them in big batches, and the first batch of 432 / 432-R type ( rear sump ) cylinder blocks with the rear-set dipstick were most likely cast alongside the second batch of PGC10 Skyline GT-R blocks. The blocks would have sat around for a few months before going on to be machined:



Interestingly, the S20 cylinder blocks are pre-drilled ( and screw plugged ) for optional dry sump application, although they were sold with wet sump. There are no 'Welch' plugs / freeze plugs / core plugs in the block, either.

 

[PS30-SB]

Cylinder head stripped down:

 

[Torby]

Thank you for posting this, this is really interesting stuff for a Datsun enthusiast! Will be following with great interest! Keep up the good work!

 

[TAZZMAXX]

Really impressed with the technology of this engine when you compare it to Ford's 2 litre OHC of the same period. There's no comparison really and it shows how far advanced Japanese automotive engineering was. Subscribed.

 

[f5twister]

great project, especially working on this iconic engine , hope i wil hear one day awesome exhaust note for real

keep going

 

[tarmac terror]

Really impressed with the technology of this engine when you compare it to Ford's 2 litre OHC of the same period. There's no comparison really and it shows how far advanced Japanese automotive engineering was.

Indeed...i lived and breathed 2L Pinto engines back in the day. Love them but they are very agricultural. Although, in fairness...they do what they say on the tin and can be persuaded to give up some decent hp & torque.


Interesting story there Alan along with some good pics!! Interested to see how this pan's out!!

TT

 

[Cris]

Thought I'd make a thread relating to an ongoing long-term project of mine. I'm building an as-close-as-possible replica of a 'PS30-SB' Nissan Fairlady Z432-R.

A little background data: The Fairlady Z432-R was the super lightweight GT race homologation version of the Fairlady Z432, built in small numbers expressly to legalise the model for use in Japanese domestic GT racing. ...

Don't suppose that this model wa also the basisof the rally versions (or where they perhaps just run of the mill cars converted)?

 

[PS30-SB]

To build an accurate replica of a 432-R, I needed to find the right base car. It needed to be fairly early production ( late 1969 would be nice but super rare, but 1970 also good ) as most 432-Rs were built in 1969 and 1970, and it would help greatly - detail wise - if it were to be a Japanese domestic market model.

Another little miracle. I found a mid-1970 'S30' Fairlady Z-L here in the UK. The Fairlady Z-L was one of the L20A ( 2 litre SOHC straight six ) engined models, and the 'L' denoted 'luxury' trim. Basically stripped, missing a fair few parts, but solid and a great base to work from. A 'poverty spec' S30-S Fairlady Z would have been a better base ( no frills, no bells and whistles, and very similar trim spec to my 432-R target ) but I wasn't looking a gift horse in the mouth. The car had been sitting in a container for a few years after a previous owner pulled out of a restoration job, and somehow it found me. A lucky break.

Tracking down the history of the car, I found it had been bought new in Japan ( from Nissan's 'Diplomatic and Foreign Sales' office at their Ginza, Tokyo HQ in 1970. The first owner was a USAF pilot stationed in Japan, and he used the car as his personal transport whilst there. A couple of years later he was posted back to the USA, and registered the car for use there ( in both Texas and California ). So how did the car come to the UK? Well, the pilot - one William Comstock - seems to have been part of a pilot 'exchange' scheme with the RAF, as he was posted to a base here in the UK and brought the ( handily RHD ) Fairlady with him. When eventually he went home, he sold the Fairlady and it's been here ever since.

I entrusted body repairs and paint to the excellent Barry at Fourways Engineering in Borough Green, Kent:

 

[PS30-SB]

Thanks for all the positive comments. I hope I'm doing justice to the excellent engineers of Prince and Nissan who created these engines and the cars they were used in....

Don't suppose that this model wa also the basisof the rally versions (or where they perhaps just run of the mill cars converted)?

That's a very good point, and perhaps even more accurate than you realise?

The first Works 240Z rally cars - the cars built for the 1970 RAC Rally, the 1971 Monte Carlo Rallye, the 1971 East African Safari Rally and the 1971 RAC Rally - were, in effect, almost 432-Rs with L-series engines.

They used most of the same super lightweight body structure of the 432-R ( special pressings made from a thinner gauge of steel ) as well as their FRP panels and plexiglass windows. They also shared the deleted spare wheel well and strengthened rear crossmember which housed the 100 litre fuel tank of the 432-R. The early Works 240Z rally cars were very special indeed. I'm a big fan.

In 1972 the FIA changed the rules, and Nissan was forced to switch to 'full fat' bodyshells for the Works 240Z rally cars. They were now obliged to use steel body panels instead of FRP, and glass instead of Plexiglass. Less in common with the 432-R, and Nissan changed their focus to higher strength but also more power.

 

[PS30-SB]

Really impressed with the technology of this engine when you compare it to Ford's 2 litre OHC of the same period.

A fairer comparison might be the Ford BDA.

I don't want to criticise the S20 when it's had so little written about it in English ( it deserves more recognition ) but it's a bit heavy and a bit long for a 2 litre engine...

One of the reasons that Prince went with a straight six for their race engine was that that's what they were selling. Prince saw itself as a cut above the likes of Nissan and Toyota, and made a big thing of 'smooth power' for their production cars. Pegged by the artificial 2-litre tax break capacity limit ( bigger engines paid much higher road tax duties ) they stuck with smooth sixes for their refinement, and that's what they went racing with. The G7 and G7R, then the GR8 were all two litre sixes, and that's the DNA of the Nissan S20.

The same ex-Prince engineers - and the same philosophy of smooth power - gave us the RB-series engines in the mid 1980s, and ultimately the almighty RB26DETT in 1989.