{"id":14024,"date":"2021-09-16T01:12:59","date_gmt":"2021-09-16T05:12:59","guid":{"rendered":"https:\/\/maxtorqueperformance.com\/staging\/?p=14024"},"modified":"2021-09-16T02:09:27","modified_gmt":"2021-09-16T06:09:27","slug":"connecting-rod-shapesand-some-new-designs","status":"publish","type":"post","link":"https:\/\/maxtorqueperformance.com\/staging\/index.php\/2021\/09\/16\/connecting-rod-shapesand-some-new-designs\/","title":{"rendered":"Connecting Rod Shapes\u2026And Some New Designs"},"content":{"rendered":"
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By\u00a0<\/span>BILL HOLLAND<\/a><\/span><\/span>\u00a0<\/span>SEPTEMBER 15, 2021<\/span><\/div>\n<\/header>\n

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Editors Note: The following editorial was supplied by Race Winning Brands and its family of connecting rod manufacturers and re-printed here on our\u00a0digital pages for educational posterity.<\/i><\/strong><\/p>\n

We know that connecting rods take a tremendous pounding with each engine revolution \u2014and in today\u2019s high-boost world the stresses are elevated to new heights.\u00a0Similarly, engine builders strive to minimize weight without sacrificing strength in order to improve efficiency and increase RPM potential, while being mindful of clearances.<\/p>\n

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Today\u2019s connecting rod choices range from popular priced forged steel H-beam models, to unique I-beam designs and sophisticated billet aluminum rods.<\/p>\n<\/p><\/div>\n

The industry has responded to these varied challenges by way of design, metallurgical and manufacturing improvements, and for input we turned to the experts at\u00a0<\/span>Race Winning Brands<\/a>, the corporate entity that consists of 10 leading automotive aftermarket manufacturers (along with Powersports-focused firms), with four of them producing connecting rods that range from popular-priced H-beam steel rods for street and E.T. bracket applications to highly sophisticated billet aluminum rods for drag racing\u2019s extreme classes. RWB\u2019s brands include rod-makers BoostLine, K1 Technologies, Manley Performance, and MGP.<\/p>\n

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Manley\u2019s unique Tri-Beam rod being machined for pin end oiling holes at 10 and 2 o\u2019clock for better lubrication.<\/p>\n<\/p><\/div>\n

Since 90-plus percent of racing engines are built with steel connecting rods, let\u2019s start there. Industry offerings range from proven H-Beam rods to highly sophisticated variations of the original I-beam design that has been employed in production engines for over a century.<\/p>\n

In fact, let\u2019s look at a Ford Model T rod; It\u2019s an I-beam design with a center-to-center length just shy of 7-inches.\u00a0 The babbit material was poured into the big end and shaped (no separate bearings) and the pin end clamped onto the wrist pin \u2014these were the days before \u201cfloating\u201d wrist pins became popular. Weight? Not really a factor as the Model\u2019s T\u2019s pistons were cast iron. Compression ratio? Try 4:1. We\u2019ve come a long way, baby!<\/p>\n

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We\u2019ve come a long way from the spindly I-beam rods used in Model Ts to special H-beam rods like those from Manley used as OEM by Ford.<\/p>\n<\/p><\/div>\n

Fast-forward to the 21st century, where Ford\u2019s LeMans-styled GT, with a supercharged 5.4L engine, came from the factory with 4340 H-Beam connecting rods from\u00a0<\/span>Manley Performance<\/a>, as did the later SVT Mustang Cobra.<\/p>\n

It\u2019s been said that the H-beam rod design came out of WWII, when aircraft engines infused with nitrous oxide in high-altitude combat experienced failures with I-beam rods. This technology migrated into the automotive aftermarket in the 1960s, with Fred Carrillo a primary mover.<\/p>\n

Today\u2019s H-beam rods enjoy advances in metallurgy, manufacturing technology and contemporary rod bolts. All four manufacturers contributing to this article, as well as others, rely on\u00a0<\/span>ARP<\/a>\u00a0<\/span>for these critical fasteners. The most popular are entry level 8740 chrome moly (190,000 psi nominal tensile strength), the popular ARP2000 alloy (220,000 psi) and for extreme duty applications the Custom Age 625+ (280,000 psi), as well as L19 (260,000 psi) and 3.5 (280,000 psi).<\/p>\n

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One thing these rods all have in common are ARP rod bolts, which range from 190,000 psi 8740 steel to more sophisticated alloys like L19 that are nominally rated to 280,000 psi tensile strength.<\/p>\n<\/p><\/div>\n

K1 Technologies<\/a>\u00a0<\/span>GM Trey McFarland, a 25-year industry veteran said, \u201cThe basic shape of the H-beam rod has not changed in decades, but it\u2019s important to note the features that make them vastly superior to OEM rods. Like others, K1 rods are forged from 4340 steel alloy. But our entry level rod comes with ARP 2000 bolts, which provides the necessary clamping force for the large majority of sportsman-level racers.\u201d<\/p>\n

McFarland added, \u201cWe have recently developed a rod for the Ford 7.3L Godzilla engine, that makes Ford\u2019s new affordable big-block engine more durable and race-ready.\u201d\u00a0 K-1 Technologies also manufactures I-beam rods for select sport compact applications.<\/p>\n

Manley Performance offers a wide spectrum of forged steel connecting rods that include H-Beam, I-beam and a proprietary \u201cTri-Beam\u201d design that combines attributes of both H-Beam and I-Beam designs.<\/p>\n

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Here\u2019s a cross-sectional drawing of connecting rod beams showing the differences between Manley\u2019s I-Beam, H-Beam and Tri-Beam rods.<\/p>\n<\/p><\/div>\n

One area that Manley has focused on is a series of rods that have been accepted by NHRA and are legal for use in Stock and Super Stock applications. They have \u201capproved\u201d rods for a huge variety of engines that include AMC 390-401, Chevy V-6, small-block, big-block and LS, Olds, Pontiac, Ford and Chrysler applications. Manley is also an NHRA major sponsor and posts contingency awards for rods.<\/p>\n

Weight is a key factor and as a rule of thumb I-Beam rods are lighter than H-Beams of a similar size. But for advocates of both designs, Manley offers an \u201cH-Lite\u201d series that\u2019s some 50 grams lighter than a standard H-Beam and \u201cTour Lite\u201d I-Beams originally developed for oval track competition are lighter yet \u2014getting down to 520 grams for a 5.7-inch small-block Chevy rod.<\/p>\n

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Manley Performance offers both H-Beam and I-Beam rods, as well as its innovative Tri-Beam design for highly-boosted applications.<\/p>\n<\/p><\/div>\n

The Tri-Beam, which is part of Manley\u2019s Turbo Tuff series, was designed specifically for highly boosted sport compact applications. According to Manley GM Michael Tokarchik, \u201cWe took our I-Beam rod and added ribs to the pin end, beam and cap which has added strength and helps maintain bore roundness on both ends. We incorporated pin oil holes at 10 and 2 o\u2019clock to improve wrist pin lubrication and undercut the beam to optimize strength-to-weight.\u201d<\/p>\n

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A batch of H-beam rods being honed on the pin end.<\/p>\n<\/p><\/div>\n

While most of Manley\u2019s connecting rods are manufactured from 4340 steel alloy, they do offer a premium I-Beam rod made from the highly desirable 300M alloy. This, of course, improves the strength of the rod and allows unnecessary weight to be pared via FEA (Finite Element Analysis). These \u201cPro Series\u201d rods are available for late Chrysler Hemi, Chevy LS\/LT and Modular Ford (including Coyote) engines.<\/p>\n

A relative newcomer in the grand scheme of things is\u00a0<\/span>BoostLine<\/a>. While the RWB engineering team behind this unique rod has decades of experience, the design was patented in 2018 and the new brand subsequently launched.<\/p>\n

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BoostLine\u2019s patented design rods are available for a variety of applications that include diesels \u2014which have been dyno tested to handle over 2,000 HP.<\/p>\n<\/p><\/div>\n

According to BoostLine\u2019s Director of Product Development, Nick DiBlasi, \u201cThe unique part of the BoostLine rod is the triangulated wide-beam design along with three machined weight pockets. This provides absolute strength, and allows us to remove unnecessary weight that does not compromise the integrity of the rod.\u201d<\/p>\n

Designed specifically to withstand the rigors of highly-boosted engines, the latest iteration of the BoostLine rod is for Cummins and GM DuraMax diesel applications. As part of the rigorous R&D that went into qualifying the product \u2014which included FEA\u2014 they were installed in engines and subjected to 2,000-plus pound feet of torque pulls on the dyno.<\/p>\n

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Are turbos mandatory? BoostLine\u2019s DiBlasi says, \u201cWhile the rods were designed for heavy-duty forced induction applications they are happily at home with nitrous engines and virtually any marine application. We have customers using them in normally aspirated engines where they just want the longest possible life.\u201d<\/p>\n

Sticklers for quality control, Nick added, \u201cAll BoostLine connecting rods undergo a rigid 25-point inspection that includes CMM, multiple visual and manual inspections along the way. We pride ourselves in having a product that\u2019s ready for installation.\u201d<\/p>\n

Aluminum rods are ideally suited for many drag racing applications as they function as a \u201cshock absorber\u201d of sorts and mitigate the tremendous shock loads that highly boosted (and fuel-burning) engines transmit to the crankshaft. The rods are also relatively light in the grand scheme of things and facilitate high RPM performance.<\/p>\n

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