Measuring the piston crown

Measuring the piston crown

By Titus Bloom: The most valuable currency of the race piston maker and also of the race engine builder is his reputation. Daily, they work around potentially destructive forces and know well the fine line between an engineering triumph and disaster. Piston-crown thickness troubles usually strike from one of two causes: error during manufacture or subsequent ill-advised power increases beyond the piston’s capacity. Here’s a new instrument that might inspire confidence. Introduced by Gibtec Pistons, it’s a piston crown checker, which allows engine builders to verify the piston crown thickness, the thickness under the valve pockets and it accomplishes the task in seconds. Built on a solid 6061 aluminum base, it features a black anodized 5/8in diameter steel post on which is mounted an upper plate that supports a dial gauge that is calibrated in one thousandth of an inch. The lower pointer projecting upward from the base is made of stainless steel. Typically, piston crown thicknesses for naturally aspirated engines and power-adder engines measure 0.150 to 0.180in and 0.200 and 0.250in respectively. Occasionally, piston-design engineers mistakenly adopt a wrong ‘start’ dimension, potentially troublesome around the valve pockets. Or if an error is made during the machining process, new pistons can be impaired by weak crowns, which, obviously, can have serious implications. One hopes the manufacturer’s programming calculations are correct, but it’s impossible to tell precisely unless the finished piston is checked. It may sound bewildering, but it is quite possible for one piston in a set of eight to suffer insufficient crown thickness. Aluminum racing pistons are remarkably resilient in how they withstand the forces and pressures of...
Androwick Returns to NHRA Pro Stock

Androwick Returns to NHRA Pro Stock

For 2016, the NHRA introduced drastic changes to the Pro Stock racing class. Teams discarded their carburetors and hood scoops, replacing them with mandated cowl induction and fuel injection electronic control units. Years of development knowledge was abandoned as teams struggled in the off-season to adapt their race cars to comply with the new systems, to say nothing of the forfeiture of horsepower in their switch from carburetion. Gray Motorsports, a top-tier team, with arguably the best group of individuals currently building engines and tuning race cars, approached Mike Androwick of Mike’s Racing Heads for advice on their new fuel injected Pro Stock program. “We sat down with Shane Gray and the guys at the engine shop and they decided the best option was to have us design and supply them with a new top-end,” says Androwick. “They felt this was their weakest area, but had a clear insight as to the way ahead and we developed it from there.” Mike and his son Mike Jr wasted no time in designing and building the new parts. “It’s not often you get opportunities like this, especially the chance to work with such a talented group of individuals,” said Mike’s son. “We were committed to living up to expectation.” Following countless hours of R&D, CAD design, CAM programming and CNC-machining, Androwick and his son handed over the newly designed top-end to Gray Motorsports. “Normally it’s a struggle to find a few horsepower in a Pro Stock engine,” explains Androwick. “However, after running our top end on the dyno, their engine guys were in a hurry to get it off and into...
Ohio Speed Shops: Chuck Fitch explains how to buy an engine package

Ohio Speed Shops: Chuck Fitch explains how to buy an engine package

By Ben Mozart: Chuck Fitch has played a pivotal role for over thirty years in the supply of engines and transmissions—often custom packages with an emphasis on completeness—and recently expanded his options by opening a new venture: Ohio Speed Shops. Fitch’s competitive advantage has always been his personal touch:”I always try to talk to my customers about their best options rather than ‘here is what’s available’. We discuss how the engine should be dressed: carbureted or fuel injection. We also inquire as to how the power package will be used. Most of the time the answer he receives is Street use with the occasional visit to the track, which generally narrows the practical choices to a couple of options. But this advice is important as the wrong choice has rarely a pleasant outcome. Often an incorrect camshaft specification results in the engine “loading-up”, making the vehicle a misery to drive. Says Fitch, “Most of us have experienced wrong choices; clearly, they are best avoided.” Interestingly, there’s an engine dyno tuning, testing and break-in service option. Again, Chuck Fitch, “We prep the engines and prime them with oil. It leads to a smoother engine installation and eliminates the inconvenience of the installer running about looking for extra parts.” This service costs $650 and $900 depending upon the type of engine and its configuration. If you have a special request, call or email Chuck at Ohio Speed Shops. And for car builders and some engine builders they provide unique sourcing of GM OE and Chevrolet performance parts.   Source: Ohio Speed Shops 536 Wyoming Ave, Niles, Ohio 44446 330-349-4930 ChuckFitch@OhioSpeedShops.com...
Reports of my death are greatly exaggerated

Reports of my death are greatly exaggerated

Never trust an unbiased printer. By Martha Maglone We read with dismay a report in the latest issue of Drag Racing Scene announcing the passing of Dave McClelland. How could this be? Dave was in fine fettle a few evenings ago when we last spoke, and a man in better spirits we could not imagine. Of course death has always been unequivocal, that is until Mark Twain issued his hilarious rebuttal “Reports of my death…” What happened was that the magazine’s esteemed editorial director, Todd Silvey, had submitted his materials for Volume 2 Issue 3 to his printer. But the printer had confused Todd’s Obituaries with his Honors columns, which is where Dave should have featured! Todd joked, “Dave may not take my calls anymore!” Happily the legendary voice of motor sports retains a strong appetite for life. The erratic Topolino McClelland, who has been announcing at drags strips for 57 years, was inducted into the Motorsports Hall of Fame of America on June 29 in Daytona Beach. An equally interesting part of his life has been his own pursuit of drag racing in his Fiat Topolino (little mouse), but not always without anxiety. The car could be woefully erratic, steering to the left or right without warning. But McClelland survived the unpredictable perils without calamity and much of the car’s later agility came from the skills of chassis and suspension specialist Roger Lamb. “The principal trouble with Dave’s Topolino was caused by bump steer, says Lamb. In common with many short wheelbase race cars of the last century with larger displacement engines installed, the steering geometry often no...
Blower Basics: What you need to know about supercharging.

Blower Basics: What you need to know about supercharging.

The most direct means to enhance engine performance is to introduce more mixture into the cylinders–and supercharging is the most effective way. Forcing fuel and air into the cylinders with a pump or supercharger increases the volumetric efficiency dramatically, by as much as 50 percent compared to normally aspirated engines. –Ron Ceridono Click here to read the full story, compliments of Classic...
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