Top. Too many engine builders fail to comply with these requirements, then blame the pistons to be at fault. Oil Ring Expander Gap Range Groove 1 – Compression Rings: Ring Gaps need to be checked. When compared to traditional cast pistons, which are not designed Light duty 3.498” bore x .0065” gap factor = .022” total top ring end gap). Many engine builders You should call FMS or somehow determine the top ring gap before adding nitrous. hypereutectic pistons: some brands of hypereutectic pistons require much larger end gaps on the top rings.please contact piston manufacturer to see if this adjustment is necessary. As I recall, the top ring sits a little higher on the K-Bs, so there's less "meat" between the ring and combustion chamber, causing the ring to get hotter. Which type of connecting rod needs to be heated to install the piston pin. Non-heat treated 390 hypereutectic alloy aluminum has slightly less strength than conventionally cast F-132 aluminum. See all 23 photos This is a piston ring grinder where the engine builder can trim the ring ends to the proper gap. 3. UEM manufactures the Silv-O-Lite OE aftermarket piston line, KB Performance Pistons (including the motorcycle division), and The Claimer Performance Piston Series. KB hypereutectic pistons will withstand alot of punishment and have respectable longevity, IF you follow the special piston to cylinder wall clearances AND piston ring end gap. A hypereutectic piston is an internal combustion engine piston cast using a hypereutectic alloy–that is, a metallic alloy which has a composition beyond the eutectic point. Hypereutectic 390 refers to a unique aluminum piston alloy that contains dissolved and free silicon. We’ve personally witnessed the upper section of a brand-new hypereutectic piston that snapped off at the oil return slots from a seized top ring, due to insufficient end gap. Find Sealed Power H345DCP Speed-Pro Hypereutectic Pistons and get Free Shipping on Orders Over $99 at Summit Racing! This is for short-track circle track racing. Recommended ring gap for Speed Pro hypereutectic pistons. ring lubrication: do not use motor oil.instead use our specially formulated oil (part # ac-9900) for quick seating and long life. Even in a mild case where the ring ends barely touch, the result can be a heavily scored cylinder wall and serious piston-ring-land damage due to this excessive load. The gap should be a minimum of .010”. uses about 16% silicon and is a cast iron piston. Ring Gap … The end gap on the second ring is 1.5 to two times that of the top ring. KB hypereutectic pistons will withstand alot of punishment and have respectable longevity, IF you follow the special piston to cylinder wall clearances AND piston ring end gap. Multiply bore size x ring end gap factor. The Keith Black piston's unique thermal conductivity, ring location and varied end use requires special attention be paid to top ring end gap. Keith Black specifically states that the top ring must gapped wider then normal because of heat retention, and top ring location has no bearing on gap … The material can be T6 heat treated to high strength and stiffness. We’ve personally witnessed the upper section of a brand-new hypereutectic piston that snapped off at the oil return slots from a seized top ring, due to insufficient end gap. _____ Check out Kalvinator Engines: http://www.kalvinatorengines.comPiston ring gap is critical to the operation of your engine. All KB motorcycle pistons come with clearance built into the piston. Cylinder should be free of any taper. What differentiates the hypereutectic cast piston from a cast piston - is its silicone content. Ring end gap should be measured with the ring square in the bore on a fresh hone. To improve ring sealing, some late model engines such as Ford 4.6L and Corvette LS1 are now using a wider end gap on the second ring. 004 x 4.00in bore = 0.016 inch ring gap; For high performance engines, the multiplier changes to add more clearance, but the math stays the same: Modified or Nitrous Oxide - 0.005in x 4.00in bore = 0.020 inch ring gap Additionally, Sealed Power's hypereutectic pistons have a DuroShield anti-friction coating applied to the piston skirt to reduce cylinder-to-piston wear. I learned my lesson after that, granted it was a high silicone content casting (12.5% or higher) which would require a looser top ring gap since less heat is leaving through the piston. They have a diamond-finished crown and piston skirt that is manufactured to exacting tolerances. pistons is you have to gap the top ring bigger or it will butt when the engine is running and lift the top ring land off the piston.... Example-Normally you would gap your rings in the .004 per inch of bore, but with a KB hyper you gap … Ring endgaps are checked, then carefully ground to proper size. Most piston ring manufacturers recommend a minimum end gap of .004 inches times the bore diameter for the top piston compression ring. C ... then bore and hone the block to fit the piston size and wall clearance. If you are building an engine from scratch you can hone out the bore and increase end gap on the rings to compensate for the added heat. See table below for proper ring end gap for your application. governor Ring gap is very critical on a hypereutectic piston. So for a 4 inch bore, the standard end gap would be .016 inches. The second ring end gap would be 4.000 x .0045″ = .018″. You can pretty much guarantee yourself piston failure if you do not follow the piston manufacturer's specs. ... A specific amount of piston ring end gap is required to prevent the ring ends from butting against one another as the ring expands as the engine comes up to temperature. The ring end gap facton for the top ring is .0065 but i … SPEED-PRO’S cast Hypereutectic material is a relative newcomer to the performance market, and has several attractive features. So, gap the top ring at 0.0285". Some hypereutectic piston designs require an increase in ring gaps. About 300 HP and 6800 max RPM. Since I have to widen the top ring gap per the way KB designs their pistons to, say .030" once again, and you're supposed to run a bigger second ring gap to prevent piston flutter, what do I do? KB HYPEREUTECTIC AND PREMIUM FORGED MOTORCYCLE PISTONS NOMINAL CLEARANCES The following standards are used on all KB Hypereutectic and Premium forged motorcycle non-coated pistons. Piston ring gap should only be measured after _____. ... pistons expand a lot more and when the engine is at operating temperature the clearance is probably identical to a cast piston that does not expand much at all. We’ve personally witnessed the upper section of a brand-new hypereutectic piston that snapped off at the oil return slots from a seized top ring, due to an insufficient end gap. The actual specification may range from .006″ to .013″ greater than the top ring depending on the application. 's catalogue explains the difference in great detail. The block deck is … These Summit® hypereutectic pistons are made with 16-18 percent silicon and a T5 heat treatment for greater strength, as well as scuff and seizure resistance. I ripped the top off of a Keith Black hypereutectic piston early in my career because the top ring gap was too tight. Ring gap for H435P hypereutectic pistons. Use the chart below to determine the minimum ring end gap. A hypereutectic piston _____. The oil rails may be installed without modifying the end gap. Jump to Latest Follow 1 - 7 of 7 Posts. Recent testing has proven that a larger second gap increases the top ring's ability to seal combustion. Find Summit Racing SUM-17350-30 Summit Racing® Hypereutectic Pistons and get Free Shipping on Orders Over $99 at Summit Racing! This larger "escape" path prevents inter-ring pressure from building up and lifting the top ring off the piston allowing combustion to get by. Re: ring end gap for Speed Pro pistons 09-22-06 07:23 AM - Post# 1006501 In response to grumpyvette I don't think the wider ring gap applies to Speed Pros or hypereutectic pistons in general. A engine built with a hypereutectic piston and a conservative ring gap is a limited by heat of combustion as already noted. Hypereutectic pistons get a bad rap because way too many people don't gap the rings properly. I building a 440 with .060 over Kb hypereutectic piston and need to know what to gap the 2nd and oil rings at? KB hypers, for instance, come with a chart that shows how much top ring gap is required depending on the application. 4. low tension rings: low tension ring sets are not normally recommended for street use. Use the piston to square up the ring in the bore, and check the end gap by using a feeler gage. Jump to Latest Follow ... Then all you do is increase the top ring gap to compensate for the fact that the PISTON is hotter. The biggest problem I remember with KB hyper. If the ring ends butt together during operation, the piston will come apart. 20 lap mains 3/8 mile dirt track. Nitrous requires a wider top ring gap than NA. A hypereutectic piston is made from a modern silicon-aluminum alloy that’s often used to cast pistons, and it’s generally considered a step better than aluminum. All cylinder work has been performed. KB pistons make more HP by reflecting heat energy back into the combustion process and, as a result, the top ring … Use this chart to determine the proper end gap for your engine. Even in a mild case where the ring ends barely touch, the result can be a heavily scored cylinder wall and serious piston-ring-land damage due to this excessive load. Anyway, if you are using Keith Black hypereutectic pistons in a mostly street, sometimes strip application, then you would multiply your bore diameter times 0.0065 to find the top ring gap. Then file the piston rings gaps to get correct gap size. Piston Ring End Gap Recommendations. Notice: Most of the second ring gap recommendations are larger than the top rings. If you're looking for pistons with an unbeatable combination of performance and value, then Speed-Pro hypereutectic pistons are for you. Too many engine builders fail to comply with these requirements, then blame the pistons to be at fault. For a street engine, multiplying your bore size by 0.004in will give you the top ring gap you are looking for. These pistons are manufactured from aluminum alloy that contains 16 percent silicon for greater strength and wear resistance. Even in a mild case where the ring ends barely touch, the result can be a heavily scored cylinder wall and serious piston-ring-land damage due to this excessive load. taper. Our Hypereutectic pistons operate perfectly with standard ring end gaps, and have conventional ring land locations. The thimble sized piston from a Cox .049 model airplane engine operates just fine with such minimal clearance that it does not even require any form of piston ring to seal the combustion gas. United Engine and Machine Company is now enjoying more than 98 years in business. Example: For a naturally aspirated street engine using a cast piston with 4.000″ bore, the top ring end gap would be 4.000 x .004″ = .016″. K.B. Adhere to the "piston" manufacturer's recommendations regarding ring gap and no one else. Maybe I am paranoid. Most engines require 0.10 mm / 0.004” per 25 mm / 1.0” of bore diameter for the minimum gap of the top compression ring. interference fit. So it seems like a false economy to get pre-gapped rings.