Building the ultimate Fiat Multipla

By Greg MacLeman

| 16 Sep 2021

Classic & Sports Car – Building the ultimate Fiat Multipla

Fiat fan John Hewett didn’t bank on having much to do when he bought his gleaming Multipla, yet beneath the smart paintwork lay a litany of issues.

But with the help of fellow enthusiasts, he has upgraded and improved the little Fiat to create the striking machine it should always have been.

Lifelong classic car enthusiast and top engineer Hewett has been putting his skills to good use recently, creating vital ventilator components among other things.

In the car world he most notably gained plaudits for an incredible scale replica of an Auto Union Typ A that he put on display at the Goodwood Revival in 2012.

Last year, with lockdown looming, the inventor, fabricator and Fiat 500 enthusiast decided to turn his hand to something very nearly as exotic as the pint-sized Silver Arrow, and almost as small: a Fiat 600 Multipla.

“I wanted an adventure with my son, Samuel,” says Hewett. “We’d just come back from Turin and had a wonderful time just the two of us, visiting The Italian Job locations.

“Our plan was to find a Fiat Multipla and drive it home together, but I struggled to track one down. All the cars in Italy in my price range were in a poor state, and I wanted the adventure of driving it home.

“I soon found out that it’s very expensive and difficult to do – you have to take the seller’s numberplates and promise you’ll post them back.It began to feel like more trouble than it was worth.”

After struggling to find a roadworthy machine that fell within his £25,000 budget, Hewett decided to cast the net wider and eventually stumbled across an apparently immaculate car in the French Alps that seemed almost too good to be true.

“I had a chat with the dealer, De France Heritage, and he was really helpful and kind,” Hewett explains. “But when I said I was going to drive it home I got the sense he thought it might not make it.

“‘They’re very uncomfortable to drive a long way, I wouldn’t recommend it. You won’t like it,’ he said. ‘It’s all right locally but you won’t want to drive a long way.’

“After getting it home by trailer and firing it up, it broke down straight away.”

Before making its way to France the car had been partially restored by an owner in Spain, but it quickly became apparent that the Multipla was worn out and in serious need of repair.

“There were more exhaust gases coming out of the breather hose than out of the tailpipe,” recalls Hewett.

“It literally had an extra hose that had been added just below the oil filler cap and it was chugging out on to the ground. It was so gutless, it probably only had about 8bhp. It definitely didn’t have the 20 it should have.”

A facelifted 1958 example, it was fitted with a 633cc ‘four’ borrowed from the 600 saloon but mated to an early four-speed manual ’box.

“Mine was a matching-numbers car but it had the very first gearbox with a little drum-operated handbrake. That was supposed to have gone when they went to this shape,” says Hewett. “Maybe they were using up what was left.”

Even in fine fettle the engine is something of a wheezer, rated at just 21bhp. Fresh from the factory the Multipla would take a full 43 secs to reach 50mph, with 60mph only achievable downhill and with a tail wind.

Things improved slightly in 1960 with the arrival of a more powerful 767cc unit, but even this larger-bored and longer-stroked version could only muster 25bhp – hardly scintillating in a machine that could carry five passengers plus a driver yet had all the aerodynamic qualities of a house brick.

The search for more power and greater reliability eventually led Hewett to the rakish 850 Sport Coupé, which gave him inspiration.

“I realised that the Coupé’s engine produced 52bhp – the most powerful version by far. I eventually found a motor on eBay and drove to Manchester to collect it when COVID-19 restrictions were briefly relaxed. It was an absolute dog; I had to throw 70% of it away.

“A few people in America had done the conversion and I was lucky to speak with Paul Casorona, who sent me a great big PDF detailing everything I needed to know, beautifully written including photographs of every stage needed to get the engine to run in the Multipla. There are so many things that need to change.”

He continues: “The 850 engine was originally canted over at an angle to fit in the low Sport Coupé, and they had to make it run the wrong way otherwise oil wouldn’t splash around inside properly.

“To reverse the direction you can either change the cam or install gears: the gear method is preferred because you get to keep the livelier Sport Coupé cam.

“As well as putting in new valves, valve seats and skimming the head on both sides, the pistons and conrods needed to be turned through 180º because they have a thrust side. I also ground and polished the head using a handheld tool.”

This changeover had other consequences, including causing the fan to go out of alignment with the radiator, putting strain on the rubber connecting band and risking premature failure.

“I ended up machining a small angle off the face of the water pump where it mates with the engine. It was very difficult to hold because it’s a weird casting, but I got it to line up perfectly.”

The conversion usually calls for an additional radiator to be fitted underneath the car, where airflow is sufficient to cool the larger engine, but Hewett was reluctant to install supplementary pipework that would make it difficult to revert the car to standard.

“My friend Tom Montagu, formerly of Radbourne Racing, suggested Evans Waterless Coolant,” Hewett says. “I found that even on the hottest day of the summer, when it was about 40ºC, the Multipla only got to 103 on the temperature gauge. You could even take off the radiator cap.

“I spent ages cleaning the heater matrix and couldn’t understand why it wouldn’t work, then I took off the hose and realised the thermostat housing had rotted away.

“They’re made out of this really poor aluminium-type cast material, it’s so cheap and nasty. I tried to warm it with a butane torch and it started to melt!

“Everybody puts a pipe straight to the radiator and forgets about the heater, but I made a replacement from brass by brazing three pieces together and fitting a thermostat. It now works perfectly.”

Another original element built to a cost was the Weber 30DIC carburettor that came with the 850 Sport Coupé engine.

“I remember Tom saying, ‘DIC by name, dick by nature: you’ll be dicking around with it constantly,’” Hewett laughs.

On Montagu’s suggestion, he opted instead for a new Land-Rover carb, creating a bespoke manifold using computer-aided design before having it milled from a block of aluminium.

Rather than fit an aftermarket performance air filter, he was able to modify a spare airbox, powder-coating it the same blue as his original.

“You’ve got that old-fashioned look still. For me it’s about how it looks as well as how it goes.”

Hewett’s network of friends was proving invaluable during the Multipla’s restoration, and none went further out of their way to be of assistance than Giorgio Casti, an Edmonton-based Fiat enthusiast who, against the odds, sourced a number of rare parts for the project.

“Hinges are impossible to find because they’re welded to the body and bolted to the engine lid,” says Hewett, “so when people scrap a car the hinges go with the body. Giorgio somehow managed to get new-old-stock ones – never before used. He could get you anything.”

Hewett was desperate to convert his benchseat arrangement to individual chairs, a desirable and costly modification due to the lack of parts availability.

“He found a set! They were terrible, but a full set. The aluminium strips on the back were absolutely ruined, bent in every direction and covered in gloss paint.

“It took me two hours to bring each one back and there are 12 in total.”

While Hewett spent lockdown working on the Multipla, the pandemic was about to hit closer to home: “My phone rang and it said ‘Giorgio’, but when I answered it was his son Rafael, who explained that his father had passed away on 5 December.

“He was really kind, his dad. He would get parts from Italy for people and would send them for nothing – he’d even pay for the postage. He just liked helping people.”

Casti’s touch appears through much of the Multipla. Hewett’s car was originally lumbered with the lowest gearing, which is great for setting off with six people on board using just 21bhp, but far less suited to modern roads.

Across its 14-year production run the Fiat 600 and its Multipla variant were available with a number of different gear ratios, and a higher-geared 600 saloon version followed, with a very similar ’box fitted to the uprated 767cc Multipla.

The later saloons, however, were even longer-legged, and none other than Giorgio was able to unearth one for his friend.

“I thought it’d had it,” recalls Hewett, “I pressure-washed it three or four times and ended up looking as if I’d just come out of a bog. I was covered from head to toe in filth. I had to use a screwdriver to dig into the dirt, it was really bad.”

“After I got it clean I opened it up, expecting it to be terrible, but it was like brand new – I couldn’t believe it. Golden oil, everything gleaming.

“I looked at the gears and there was nothing wrong with any of it, so I put it in the car to see how it went. It’s absolutely perfect.

“Now it will probably do 75mph. The Sport Coupé did 90mph, which was immense from a 903cc engine, but it’s the aerodynamics that slow the Multipla down.”

The extra power has taken away none of the Multipla’s charm, and it buzzes along with the same high-tempo clatter that it produced when driving around the busy Latin streets in period.

It looks the part, too, thanks to the paintjob that was carried out in Spain, but the list of jobs continued.

“Everything that was done to it when it was first restored was bodged, really,” Hewett admits. “The owner had it repainted and put in a new interior and that was it

“I had to respray the engine bay because he didn’t do it when he painted the outside. It could have been a concours car if he had only done things a bit better, it’s such a shame.”

After a year of hard graft, Hewett is putting the finishing touches to the little Fiat.

The vinyl interior was refinished in leather in a contrasting blue, while a kind neighbour donated carpet offcuts from which mats were made, piped with brown hide pinched from an old leather sofa.

A period roof-rack was added, too, with oak slats taken from his son’s old bunk beds, while missing rubber feet were recreated using a mould to cast replacements: “I recycle stuff if I can – not to save money, I just hate to see things go to waste.”

All that remains is to plan the adventure that first inspired him to buy the car, that epic road trip with his youngest son: “I would love to go to Turin again and drive it around the rooftop track at Lingotto. We love the city.”

Images: Olgun Kordal

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