Putting the Squeeze on

Putting the Squeeze on

The Importance of Compression Ratios and How to Measure Them: Since race pistons in domestic V-8 engines move up and down in excess of 100 times per second, replacing them is a normal part of a racer’s routine. NHRA Top Fuel and Funny car teams replace them after every race pass and every second qualifying pass. Pro Stock teams replace them after every 40 passes approximately, and weekend warriors replace them every 12 to 18 months, sooner if their engines are nitrous-assisted. Read the complete story as it appeared in Maximum Drive magazine’s 2015 Sept/Oct...
Ovality and other guarded racing piston shapes

Ovality and other guarded racing piston shapes

By Titus Bloom: Gibtec, makers of custom billet competition pistons reveals… Below their ring lands, pistons are neither round nor do they have parallel sides. Instead they have a larger diameter towards the bottom, between the base of the piston and the piston pin hole. They become progressively smaller toward the top of the piston, which is round because, to achieve proper sealing, round rings operate in round cylinders . The smaller diameter piston crown allows for greater expansion in a region closest to the heat source. Ovality, which means out of roundness, is necessary in all pistons to allow for thermal expansion. It also compensates for deflection of the piston skirt caused by side loads. Pistons are manufactured with single, double or triple ovality and the ovality is best measured by a precision roundness form measuring machine. Ovality in simple terms means the piston is narrower along the piston pin axis (the minor axis) than the thrust axis (the major axis). Because ovality is a function of heat, and therefore the growth the piston is likely to encounter, it is the amount of ovality assigned to a piston that’s the clever part. Ovality values differ, depending upon whether the engine is naturally aspirated, supercharged, turbocharged, or charged with nitrous oxide. Obviously, heat, cylinder pressures and side loadings are much less in the naturally aspirated engine and hence less piston ovality is required. Correct ovality usually manifests itself in the form of a bearing area. This is the area in the middle of the piston skirts that rides in the cylinder and it’s surrounded by a boundary of piston...
Impressive diesel gains: 2.1lb weight-saving per cylinder

Impressive diesel gains: 2.1lb weight-saving per cylinder

Irvine, CA: At CP-Carrillo, two hybrid combinations are in the final stages of testing. One is designated for the common rail 5.9 liter Cummins using a Duramax pin size and compression height with a rod length of 0.856in longer than stock. The other combo is developed for the 6.6 liter Duramax, which comprises a long-rod diesel arrangement with a Top Fuel piston pin. The connecting rod is 0.202in longer than stock. The weight saving is not yet known on the Duramax combination, but news of an impressive 2.0lb approximate saving per cylinder has emerged for the Cummins. Though prototypes are already in use in Truck Pulling contests, CP-Carrillo’s long-rod combinations were initiated for drag racing. Company’s Rick Canning said that with the right camshaft installed the Cummins diesel will rev to 6,500rpm on the snap-of-a-finger. “It’s easily achieved,” he says, “when there is significantly less reciprocating mass attached to the crank!” The test Cummins, which was dynoed with a stock camshaft, generated 1,000hp @ 3,200rpm and produced 1,500lb ft of torque. What happens next? Apparently, the engine is to be re-cammed and installed in a truck puller. When CP-Carrillo created the new Cummins hybrid connecting rod 0.856in longer than the stock counterpart and incorporated a Duramax pin size, a reduction in pin diameter resulted: from 1.575in to 1.358in. The new pin is also shorter. The compression height is also changed from a stock Cummins to Duramax, which measures 1.946in. The difference between the Cummins compression height with the pin change is 0.856in. This instigated the longer connecting rod, which improved the rod-to-stroke ratio by reducing the side load on...
CP-Carrillo: X-style pistons for power-adder engines

CP-Carrillo: X-style pistons for power-adder engines

Irvine, CA: CP-Carrillo is introducing a new X-Style series of pistons for power-adder engines. Available for Top Alcohol Hemi applications with plus or minus 4.467in bores and Hemi canted valve for Pro Mod with plus-or-minus 5.000in bores, these pistons include several advanced features including the ability to run narrower rods and shorter pins, often resulting in reduced weight for most applications. BUILT TO LAST Manufactured from 2618 T-61 alloy, these pistons utilize an “X” forging for added structural support and durability. In addition, they can be designed with buttons or with wire locks and include vertical or lateral gas ports as well as forced pin oiling. OTHER TECHNICAL ELEMENTS Developed through rigorous testing and R&D – including recent wins in all the alcohol classes – the X series is available for IMMEDIATE delivery and suits most popular Dragster, Funny Car, and Pro Mod-type applications. DROP-IN READY Join the winning race teams that have chosen CP-Carrillo pistons and rods, and get them off the shelf! CP-Carrillo’s X-style pistons are ready to drop in to an engine and should improve horsepower and durability out of the box.   BACKGROUND CP-Carrillo is a company totally dedicated to pistons and connecting rods. Experienced sales specialists provide unique piston and rod solutions for myriad engine applications. The company continuously endeavors to combine manufacturing excellence, product guidance, and ongoing technical support to effectively address customers’ needs.   For more company information please review our website: www.cp-carrillo.com CP-Carrillo is a member of PANKL Racing Systems. Contact: CP-Carrillo 1902 McGaw Irvine, CA 92614 949-567-9000 phone 949-567-9010 fax...
The curse of the round wire lock

The curse of the round wire lock

By Bertie Scott Brown, January 28, 2015   When a round wire lock, the spring-loaded device that retains the piston pin within the pin towers, comes out while the engine is racing, it releases a fanatical frenzy, a chain of events that most engine builders describe as catastrophic. It is an insecurity within the racing engine most dare not think of. Recently, however, a Californian engineer shook the establishment, when he not only cured the curse but also devised an ingeniously simple method of installing and removing them. https://www.youtube.com/watch?v=Kgdosv29Frk Karl Ramm, who has been engineering racing pistons for almost twenty years, has devised a new style of wire lock: the Kramm-Lox®. Characterized by its 90 degree tang, which resides within the existing pick lock notch, the Kramm-Lox importantly will not spin. Equally appealing, this non-rotating lock requires no modifications to the traditional piston. Furthermore, Ramm was also the inspiration behind a tool (Patent Pending) that makes them easy to install and remove. Also worth noting, the tool negates the danger of scratching the pin bore; it also removes the threat of eye injury, a comforting distinction from the notorious, flying spring-loaded locks! In addition, by keeping the wire lock stationary in the pin bore groove, Kramm-Lox avoid other self-destructive traits. If the traditional round wire lock rotates placing its gap at the top of the pin bore, particularly in high-revving long-stroke engines, the lock can distort and can pop out. The extreme jolt that occurs as the piston changes direction at the top of its stroke can momentarily change the shape of the lock. “I just started using Kramm-Lox,”...
Nitrous: the race tuner’s biggest challenge

Nitrous: the race tuner’s biggest challenge

By Fergus Ogilvy, February 4, 2015 Starting a competition piston company in the second decade of this century could be a bleak proposition. Finding new customers isn’t easy. Engine builders have a stubborn tendency to remain faithful to their existing suppliers, unless something goes awry. You could play the game grimly and die of ulcers or you could play it with a light heart and dedication and perhaps survive without losing sleep. Gibtec Pistons, the Denver-based operation did exactly this. But they had one other valuable resource to rely upon: decades of experience at the competitive edge, including several ten-year development programs with NHRA Pro Stock teams But when asked where they see the biggest challenges in race engine tuning, company founder, Robbie Giebas, responds with one word: Nitrous!  Why so? “Well, the top tuners will tell you nitrous engines have never been completely mastered—there’s still an element of mystery about them. Nitrous oxide induction requires a totally different approach, and it’s a volatile science; if the tune-up is off a little, parts need replacing. “Unlike the turbo or blower guys, who might get fifty or sixty runs from their pistons, when those nitrous guys are really pushing hard they’re replacing rings every three or four runs—it resembles the Top Fuel class in many ways. If they ease off a little on the tune-up they’ll become uncompetitive. And when the racing gets close, they’ll routinely dismantle the engine after every pass. Leak-down tests, ring end-gap checks, raised ring lands, pinched rings these are constant topics in their world.” What provokes a raised ring land or a pinched ring? “Race...