Oil Piston Rings

Rescue: Reanimating Eric Schmiege's Dead Rat Motor, Part 2 - Hot Rod Network

Stronger, bigger, and better, the now-469ci big-block Chevy drops back into the 1965 Bel Air. You’d think there’s plenty of room in a fullsize Chevy, but Smith says, “It was difficult to get the engine in and clear the carbs with just a single-chain hoist. We could have used one of those engine-tilter chains with the adjustable leveler.”

When the big-block Chevy in Eric Schmiege’s 1965 Bel Air swallowed a nut, it cracked a cylinder wall and damaged a piston. Further analysis by former HOT ROD editor Jeff Smith revealed an out-of-square block with excessive cylinder-wall taper and excessive main and rod bearing clearances. Last month, Jim Grubbs Motorsports sleeved the cracked cylinder, bored the engine 0.070-inch over, and remachined the block to square it up. Smith then reassembled the block, installing new SRP forged pistons and premium rings. He also replaced the Bel Air’s old hydraulic flat-tappet cam with an Isky hydraulic-roller profile that better matches the Bel Air’s drivetrain gearing and Schmiege’s driving style. However, piston deck height, valvetrain, oil system, and driveability issues still remained to be dealt with.

The Fix: Deck Height
On steel-rod engines, high-perf big-block Chevy builders usually shoot for near-zero piston-to-block deck heights (the piston deck is about flush with the block deck at top dead center, or TDC). With typical 0.038–0.041-inch compressed-thickness composition head gaskets, this achieves good quench with the Rat motor’s complex combustion chamber and still leaves an adequate piston-to-head, high-rpm clearance safety margin.

That was certainly Smith’s original intent, but, as he explains, “Before we sent the block out to Grubbs for repair and machining, we checked the old piston-to-deck clearance and found the block decks were not even close to square. They were out almost 0.008 inch relative to the crank centerline front-to-rear with the front portion high, which is why we had Grubbs mill the block to square it up. But now when we went and installed the new pistons, we discovered they were sticking up out of the block by about 0.013 inch on average, probably because the deck had been previously milled in a prior rebuild, but not relative to the crank centerline. Fortunately, Fel-Pro saved our bacon with its 0.053-inch compressed-thickness MLS [multilayer steel] PermaTorque gasket that also offers superior sealing potential with the proper deck surface finish. If our deck was zero, we would have used a 0.041 head gasket, and the compression would have been almost exactly the same.” Even with all the deck and head milling, piston-to-valve clearance was still more than ample, coming in at 0.190 inch or higher at the closest approach for both the intake and exhaust valves.

SRP’s pistons were 0.013 inch above the block deck at TDC (top) causing both excessively high static compression for pump gas as well as inadequate piston-to-head clearance. Fel-Pro came to the rescue with its thick, 0.053-inch compressed-thickness MLS head gasket (center) yielding a friendly 0.040-inch piston-to-head-deck clearance value. It also reduced the compression ratio to a pump-gas-friendly 10.03:1 with the Edelbrock heads’ 108–109cc chambers (as measured by Smith, bottom). To use an MLS gasket, both the head and block deck surfaces must be mirror-smooth as they were on Schmiege’s newly machined parts. Fel-Pro offers MLS Rat-motor gaskets in 0.041-, 0.053-, 0.061-, and even 0.071-inch compressed thicknesses. Using a valvespring micrometer (top), Smith set up Isky’s hydraulic-roller-cam-compatible springs with 120 pounds of pressure at a 1.875-inch installed height. “We had to add 0.060-inch worth of shims (center) to get the installed height correct on Edelbrock’s large ‘roval’-port heads,” Smith explains. “That’s in addition to the steel spring seats.” Fully assembled here on Edelbrock’s Performer RPM aluminum heads (bottom) Isky’s dual with damper...

Source: www.hotrod.com

Ural Upgrades Its Engines For 2019 - Cycleworld

For 2019, Ural announced technical evolutions to keep the personality of its motorcycles the same while aiding refinement and meeting these emissions requirements. The result is the same Ural, but with a slew of all-new components. Most of the changes revolve around the top end of the engine. From what we've seen, the bottom end is a carryover.

The pistons are all new. From a manufacturing standpoint, they’re now gravity cast from NASA 388, an aluminum/silicon alloy, for improved heat resistance. In addition, there are Teflon-inlaid skirts to reduce friction, a hard-anodized crown and top ring groove for temperature resistance, a phosphate-coated piston pin, and optimized piston ring groove tolerances.

The fuel-injection system is also all new. Keihin throttle bodies are utilized and feature a TPMS and electronic idle speed control. These changes are aimed to improve throttle response, improve “start ability,” and provide a more stable idle. It is now a closed-loop system, with a new fuel injector, new fuel injector location, new self-priming, in-tank fuel pump with integrated filter and pressure relief, and new catalysts, all with the aim to reduce emissions without reducing power. If all this sounds a bit too modern, have no fear, Ural enthusiasts, because it still has a kickstart.

Ural states the goals of all these changes clearly, “Our goal was to improve performance and reliability while meeting or exceeding ever-tightening emission control requirements.” With a fair amount of ingenuity and an adherence to what makes Ural unique, these changes sound like a win-win. Who doesn’t like a cooler-running motor, that’s more reliable and cleaner, all while retaining its unique character? We’re excited to test these changes soon. The 2019 models hit dealerships in January, and pricing starts at $16,999.


Many products featured on this site were editorially chosen. Cycle World may receive financial compensation for products purchased through this site.

cycleworld.com is part of the Bonnier Motorcycle Group, a division of Bonnier Corporation.

Copyright © 2018 Cycle World. A Bonnier Corporation Company. All rights reserved. Reproduction in whole or in part without permission is prohibited.

Source: www.cycleworld.com

If That Is A Piston, What Is This? - Cycleworld

Why have pistons atrophied to almost nothing? In this example from a Honda CRF450R motocrosser, all we have is a thin disc that is enough to locate the piston rings, two bosses for the wrist pin that connects the piston to the connecting rod, and little skirts.

The up-and-down motion of the piston produces a shaking force. You cannot balance all the shaking force of an engine by adding counterweights to the crankshaft. You can reduce the vibration, but you can’t make it go away.

Also, in a very high-rpm engine, moving up and down as it does, the piston produces very large bearing loads. Those bearing loads translate into friction, which is subtracted from the horsepower that your engine can send to the rear wheel.

Manufacturers therefore make pistons as light as possible, getting rid of everything that isn’t necessary. This particular example is large, but the center of the dome is quite thin. What happens to the heat of combustion that is collected by this surface?

Related: Why Does The Exhaust Valve Have A Hard Life?

With traditional pistons, that heat is conducted out to the cylinder wall. But this piston dome is large and that is a great distance for heat to flow. Normally, to conduct all that heat away from the center of the dome, the dome would be thick—a broad avenue for heat.

Instead, a small oil jet is placed in the crankcase, which sprays oil underneath the piston, hits one side, splashes across under the dome, is deflected down the other skirt, and falls back into the crankcase. That oil cools the piston dome, allowing it to be made thinner.


Many products featured on this site were editorially chosen. Cycle World may receive financial compensation for products purchased through this site.

cycleworld.com is part of the Bonnier Motorcycle Group, a division of Bonnier Corporation.

Copyright © 2018 Cycle World. A Bonnier Corporation Company. All rights reserved. Reproduction in whole or in part without permission is prohibited.

Source: www.cycleworld.com


Piston Rings | Hastings Manufacturing

At Hastings, we manufacture a bold and broad offering of piston rings—one that spans thousands of applications for virtually any engine. With the most comprehensive line of piston rings, compression rings, and oil rings in the world, we have a piston ring for practically any application—racing, automotive, heavy-duty transportation, agriculture, industrial, small engine, and more.

Piston ring - Wikipedia

A piston ring is a split ring that fits into a groove on the outer diameter of a piston in a reciprocating engine such as an internal combustion engine or steam engine.. The main functions of piston rings in reciprocating engines are: Sealing the combustion chamber so that there is minimal loss of gases to the crank case.

Kaydon Ring and Seal piston rings for diesel locomotive ...

Medium Speed Diesel Engine Piston Rings Kaydon manufacturers power piston rings, turbocharger seal assemblies and lower liner inserts for most models of EMD, General Electric and Alco medium speed diesel engines found in locomotives, workboats, and industrial/municipal power generation facilities.

Shop High Performance Piston Rings Online - Deves.com

About Deves. The deves line started in sweden about 1932, and was manufactured by bildeve i stockholm ab - makers of precision car lifts, industrial lifts and hydraulic elevators.

Manufacturer of Hastings piston rings including Flex-Vent ...

Hastings Manufacturing, located in Hastings, Michigan USA, manufacturers piston rings for worldwide engine manufacturers, automobile aftermarket, and engine rebuilders. For over 90 years, Hastings has been designing and making oil and compression piston rings for cars, trucks, tractors, motorcycles, boats, compressors, and race cars. Hastings invented the three piece Flex-Vent and Hyper-Vent ...