Patrick Racing

Nigel Patrick served a rather speedy apprenticeship in the profession of drag racing. In 1977 he began collecting his first Christmas-tree reaction times, and by 1978 he’d made a quantum leap to the top of the Pro Street class, dominating the field three years running. He earned number-one plates from two sanctioning bodies, and quickly upped the ante by entering the rarefied atmosphere of Funny Bike competition, building and racing turbo, nitro-injected, and blown alcohol-injected E.T. eaters.

His efforts were finally rewarded in 1984 with an MDRA National Championship in Funny Bikes, and the AMA Drag Bike National Championship in Top Fuel, a serious drag race double-header. A year later, Nigel opened the doors of his new high-performance facility, Patrick Racing, in Fountain Valley, California. Once operating in earnest, he channeled his considerable talents into research and development, focusing on cylinder heads and normally aspirated engines.

Acknowledged worldwide as an expert in high-performance cylinder heads and precision engine building, Nigel utilizes an air flow bench and Superflow engine dynamometer in his workshop. In addition, and perhaps more importantly, Nigel invested in a Haas VF-0 vertical machining centre, and TekSoft CAD/CAM design software for his PC. This setup enables Nigel to literally sculpt billet cylinder heads from blocks of raw aluminium stock. His high-performance engines are in use by many street performance riders and race teams, some of them his direct competitors.

Nigel’s CNC-machined heads for Harley-Davidson Twins are cut from solid, 8.5” square, 25-pound blocks of aircraft-quality 6061 T6 aluminium. Patrick’s cylinder heads are more robust and precision-cut than their stock counterparts, and much more aesthetically pleasing. Nigel’s success with these heads is due to his balanced desire for both their looks and the punch that they deliver.


Machining his way down from the 25-pound block to the completed 10-pound unit involves some fairly complicated processes.

“As it turns out,” Nigel says, “it actually involves some five different moving axes, something I wouldn’t be able to do without the Haas rotary table.”

Nigel utilises a fully-integrated Haas TRT-310 tilting rotary table – giving him access to various complicated angles on the part, and enabling him to form the many intricate shapes and contours of the heads with a single setup.

“Actually,” Nigel says, “it’s really a high-tech way to manufacture these high-performance heads. Each one is a perfect clone of the original, because of the super-tight tolerances the Haas holds. I can maintain 0.0001 of an inch accuracy each and every day.”

When the process is over, each perfect, 10.5-pound billet head has been through five different setups on the Haas VMC, and has a machined surface accuracy of 0.0002”. All major machine work has been completed, including the finished external shape, the receptacles for the valve guides and seats, and all the tapping and drilling to hold the rocker boxes, intake manifold and exhaust pipes.


Nigel is able to machine 30 heads at a time before moving on to the cutting of valve seats, and the flow-dynamic porting that gives these heads that extra performance boost that Harley riders are after.

To date, Patrick Engineering’s product line includes billet heads for both Harley-Davidson Big Twins and Sportster models (1984 to present). In response to overwhelming customer demand he offers all cylinder heads in eight different bolt hole patterns, with even more variations on the way.

In the past two years, business has been so successful that Nigel needed to purchase another CNC machine just to keep up with the orders. In December 1995, when shopping for a new machine, he only cared to look through one catalog.

This time, he purchased a Haas model VF-4 with a larger xyz envelope to accommodate the odd shape of the billet heads. The VF-4 gives him a little more working room, and speeds up production enough to make the extra cost worth the investment. Although his original Haas VF-0 is still in daily use churning out perfect copies of the Patrick performance heads, it continues to provide close-tolerance finishes as good as the first day it was used.

Nigel Patrick’s success has been built on solid design, and the ability to provide that little bit extra that customers sometimes don’t expect. “I’m proud of the extra-heavy-duty heads I’m able to produce on the Haas machine,” says Nigel. “They’re about a pound heavier than the stock units, mostly because of the extra material around the combustion chamber ... of course, they’re also much stronger, since they’re made of aircraft 6061 T6.”

“You know, I’m also proud of the fact that I’m one of the only after-market manufacturers of this quality of performance parts using an American-made CNC mill,” said Nigel. “The Haas machines have served me well, and I’m glad the parts I make for American bikes are made in the USA on an American-made CNC machine.”