Car Restoration Projects
Honda adds two wheels – the S600
The 1960s was a boom era for the Japanese motor industry and one of the key players was Honda. Having become the largest motorcycle manufacturer in the world, the company wanted to expand into car production.
The company’s founder, Soichiro Honda, was eager to tackle new frontiers and had assembled a team of forward-thinking designers and engineers.
He’d already had moderate success with a small Japanese-market delivery van and figured that a sports car would be an excellent way of achieving global recognition. That success would flow down to the popular car market ,where the volume sales would be.
He backed this with an ambitious Formula One effort – the first for a Japanese company – and one that proved successful and supported the marketing of the company’s road cars.
The very astute Mr Honda was vindicated by his ambitious Formula One foray, when Honda-powered F1 cars (Williams and McLaren) won the Constructors’ World Championship six times, from 1986 until 1991.
When the 1962 two-seater, convertible sports car was first shown, as a prototype, it was powered by the van’s little 360cc engine, but soon a 500cc, then later a 600cc and finally 800cc versions were produced.
They were pretty cars with inoffensive styling, which broke no new visual ground, but the engines were probably the most remarkable parts of these Honda sports cars. Some of their features were far more akin to motorcycle engines than car power-plants.
Standard Honda S600 engine
These tiny, but sturdy, twin-cam, four-cylinder engines revved to an amazing 9000rpm. The larger multi-carburettor units also featured a roller bearing crankshaft.
Unusually, the final drive was by chain on all but the later S800s, which changed to a live axle design. The chain drive units were independently suspended from the ends of a chassis-mounted diff and half-shaft ‘axle’.
Note the chassis-mounted drive ‘axle’ with trailing-arm chain drives at each end.
A hatchback coupe version was added to the range a few years before production finally ceased in 1970. By then over 25,000 had been made.
The Honda S600 and S800 were marketed widely outside Japan, including in the USA, Australia, England and in parts of Europe.
Matt Hill owns one of these little Honda sports cars: a 1964 S600 that he purchased at a Shannons’ auction, held during the Sydney Motor Show in 2004. He was smitten by its uniqueness and knew it was a rare find.
The engine wasn’t running and he guessed it would be quite a journey to restore his winning bid’s roadworthy fitness – a guess that he soon found to be very true.
The engine, a DOHC, water-cooled, four-cylinder, in-line of 606cc capacity was the first item on his agenda.
As soon as the Honda arrived at Matt’s house, his first task was to get the engine running.
“When I finally had it fired-up I found it was leaking water,” said Matt. “And then I discovered that the cylinder head was the culprit.
“I removed the engine and separted the head, then took it to an engine specialist, who told me it was beyond repair.
“Then I went in search for a replacement head and one of the contacts turned out to be a fellow who I was bidding against for the car at the auction.
“He said all that he was after were the special high-performance racing carburettors that had been fitted to it.
“I had no idea that they were non-standard and special.”
Matt’s engine has non-standard carburettors
Matt’s next contact was a guy who had worked for Honda Australia and was a wealth of knowledge.
“He found me a second-hand head and suggested I buy a full engine kit, in order to fully recondition the engine and reduce the risk of any further problems arising,” said Matt.
Matt took the used head to a machine shop, where it was crack-tested. That revealed a ‘spider’s web’ of 16 hairline cracks, tracking from the spark plug holes across to the valve seats.
“Luckily I found an outboard engine specialist who made a first-class repair, skilfully welding and machining it,” said Matt.
With the head repaired and the engine dismantled and cleaned, it was time for assembly. Matt discovered that the engine reconditioning kit contained 48 rubber ‘O’ rings and the only gasket was the one mating the head to the engine block.
“I had to cut the remaining gaskets by hand and the ‘O’ rings were very close in size, with only a millimetre or so separating their diameters, so each fitment was not a job for the faint hearted,” said Matt.
With the Honda’s engine now back in one piece, the next job in the engine area was to synchronise the four carburettors.
“Darren at Milton Tyre Service (NSW South Coast) spent almost a full day fine-tuning them for smooth running, maximum performance and economy,” said Matt “And thanks to Darren it now runs like a dream.”
With standard spec’ Keihin carburettors, the engine produced a claimed 57hp (43 kW) at 8500rpm, ex factory. However, with the high-performance, larger throat and butterfly-operated carburettors it must be somewhat higher.
It drives through a four-speed box, with synchromesh on the top three ratios, to independently suspended, sealed roller chain drives to each rear wheel.
According to Honda, the little S600 had a top speed of 140km/h when new, but Matt said he wouldn’t be pursuing that number on the speedo to check it!
Honda built 3912 roadsters in 1964, with production climbing to 7261 convertibles and 1519 coupes in 1965. Production dropped off in 1966, as Honda was shifting to the S800, with only 111 roadsters and 281 coupes made. That tallies to 11,284 convertibles and 1800 coupes built, over the S600’s three-year life span.
Matt reckons his little Honda is rare, interesting, fun and affordable – “What more could you ask of a classic?” he wants to know.
Chain drive/suspension units in detail