Stuffing Ariel’s big square four motor into Norton’s legendary featherbed frame is a tricky process that not everyone can get right. But Jerry Romano thought he had a plan.
Four in a bed.
If you wanted to find Jerry Romano’s Square Norton special at the October 2009 Barber Vintage Festival, all you had to do was follow the crowds. Every time Romano parked his beautiful Ariel-Norton special, folks would stop what they were doing and gather round.
A “retired wrencher from General Motors, just an old shop rat,” as he calls himself, Romano makes his home in Michigan. He has a number of restoration projects under his belt, including BSA Gold Stars, Spitfires and a Rocket Gold Star, as well as Vincents, Triumph Twins and a 1929 “cammy” Velocette KN.
Among all the parts he accumulated along the way were a couple of Norton Featherbed frames and an Ariel Square Four 4G MkII engine.
So he thought: “What about putting the Square Four engine in the Norton frame?”
Many have tried to fit Edward Turner’s double-twin into a Norton Featherbed frame, and most have abandoned the attempt. Those who have succeeded usually end up “cutting and shutting” the iconic frame’s tubing, spoiling its integrity and compromising its strength and rigidity. What makes Romano’s Ariel-Norton all the more special is that he was able to fit the big lump without chopping the frame.
“I measured it and it looked like there was enough room,” he says, “so I assembled a set of empty cases and got them into place without any trouble. I put the engine as far forward as possible and moved the swingarm mounts. I used the stock Ariel primary case and found it was an inch bigger than it needed to be, so I took half an inch out of it.”
The transmission plates also had to be trimmed, and the frame tubes “eased” to allow the engine to be shoehorned in. Aside from the problem of getting the powertrain into the frame, “everything else flowed,” says Romano. However, there was no room for the Manx oil tank, so he mocked one up out of cardboard to fit. The result looks like a Manx oil tank and holds the requisite four quarts of oil.
The rear wheel and drum brake came from a conical hub Triumph, and onto the front of the “slimline” Featherbed frame went a fork set, brake and front wheel from a 1949 “Garden Gate” Manx Norton. A Manx short-circuit gas tank and Manx seat added to the period Norton look.
Romano found a set of alloy blade fenders and fabricated braces to fit, added a Smiths Chronometric speedometer, and the rest seems to have been assembled without trouble. But what’s most impressive is the way it looks like everything was intended to go together. The frame could almost have been made to wrap around the big four-cylinder lump and its Burman gearbox.
Romano’s 1957 four-pipe 4G MkII engine also has a connection to legendary Ariel four tuner and one-time Egli-Square Four manufacturer Tim Healey and includes a number of improvements for performance and reliability. When Romano started on the rebuild, he discovered the engine was stamped ATA #16, indicating it was a Healey motor. Another clue was the Lucas four-cylinder magneto instead of the usual distributor. Healey engines also had a special camshaft and an improved oil pump, filter and cooler. Other than shaving the cylinder head for increased compression (the Healey used a lowly 7.5:1),Romano has left the engine stock, which should mean it’s making a little more than the 52 horsepower of a regular Healey motor. After consultation with UK Ariel specialists Draganfly Motorcycles, he also decided to retain the stock SU carburetor.
THE SQUARE FOUR STORY DATES back to 1928 when Edward Turner, then a motorcycle dealer, showed his innovative design to Ariel boss Jack Sangster. The sophisticated 500cc overhead cam Ariel Square Four was launched at the Earls Court motorcycle show in London in 1930. The original 4F Square Four used two crankshafts connected by helical gears with the overhead cams driven by a shaft and bevel gears. Over the years, the Square Four became 600cc, then a full 998cc with the OHC being dropped for more conventional (read: cheaper) OHV gear. The first post-WWII machines used an iron cylinder block and head (4G MkI, distinguishable by the two-pipe exhaust header), but with wider availability of aluminum, the cylinder head became light alloy with four header pipes (4G MkII).
When parent company BSA Group pulled the plug on Square Four production in 1959, Ariel racer Tim Healey bought up a huge collection of spare parts. He planned to go into production with the Healey 1000/4, using the Square Four motor in an oil-bearing spine frame designed by Fritz Egli. Later versions used Ceriani and Spanish Betor forks and a 230mm double sided Lockheed disc brake. At just 355 lbs. (161 kg) dry, the Healey 1000/4 was good for 126 mph. Performance was better than sales, however, and Healey abandoned the project after selling just 28 machines.
ROMANO’S COMPLETED Ariel-Norton weighs just 410 lbs. (185 kg) complete with a tank of gas, so it makes the most of the big motor’s torque. “Rolling on the throttle in first gear will break the rear tire loose,” says the owner.
“The work I had to do to the frame was really neat,” he says. “I like a challenge.”
But what Romano says he finds most gratifying about the finished project is the reaction of people who see it for the first time. “’I never knew Norton made a four cylinder,’ is a common response,” he says. “Even the guys with newer bikes and Harleys say ‘that’s cool.’ The president of our local Norton Owners club was going to pay my dues and make me an honourary member!”
Thinking of building one yourself? Jerry Romano has some advice: “If you’re mechanically inclined, and have access to a lathe and mill—have at it! You’re going to have to make a lot of parts …”
– Robert Smith (issue #270)