High-Performance Oil Pumps 1HZLURQDOOR\SXPSVDUHFDVWZLWK less porosity for a yield strength of 70,000 PSI. Pumps are blueprinted and precisely PDFKLQHGZLWKIXOOÀRZVKDIWRLOLQJH[DFWPHVK JHDUVDQGDQWLDHUDWLRQEOHHGRIIIRUH[FHSWLRQ - DOKLJK530OXEULFDWLRQ&KHY\³2(3OXV´DQG ³6SRUWVPDQ665´VHULHVLQFOXGH DQG 36,SUHVVXUHUHOLHIVSULQJV
GM LS Series High-Volume/ High-Performance Oil Pump By Schumanns
*0/66HULHVRLOSXPSLVHQJL - neered for applications with up to 500 horsepower and includes an RYHUVL]HG ´,'RXWOHWSRUWWR block with an O-ring seal. Pump additionally features machined and radiused internal oil passages for in- FUHDVHGRLOÀRZ6ROGFRPSOHWHZLWKWKUHH color-coded pressure relief springs in 60, DQG36,UDWLQJV Part No. Description AFM20330 SB Chevy Oil Pump Pressure Relief Springs 6SULQJV¿W$)0+LJK3HUIRUPDQFH2LO3XPSV Part No. Description AFM20313 GM LS Series Oil Pump AFM20331
O.E. Plus
Sportsman SSR
Description
Small Block Chevy 262-400 Standard Volume
AFM20315 AFM20317* AFM20316 AFM20318* — AFM20319* †
High Volume
High Volume, Quick Change Relief Spring
Standard Volume, 3/4" Pickup High Volume, 3/4" Pickup
AFM20320 AFM20322
— —
GM LS Oil Pump-To-Crank Center Alignment Tool Kit, Aids Pump Installation
Small Block Ford 289-351W Standard Volume
AFM20323
—
AFM20314
High Volume
AFM20324 AFM20325 ‡
* Includes additional relief springs † Includes anti-cavitation plate ‡ Gear pressure balanced to prevent hydraulicing
AFM20313
Pressure Relief Spring, 65-70 PSI Pressure Relief Spring, 80-90 PSI
AFM20314
The How’s, What’s, Why’s and Where's of Blow-By By Jim Kaekel
The term blow-by certainly isn’t viewed in a positive light, yet each and every internal combustion engine, regardless of brand, builder, or bud- get, is subjected to it. Blow-by, also referred to as crankcase pressure, occurs during the combustion process when burned gases leak past the piston rings and into the crankcase. The rotation and speed of the rotat- ing assembly, which not only cause windage, contributes to crankcase pressure, as well. Crankcase pressure is released through the breathers, even to the H[WHQWRIFDXVLQJWKHPWRGULSRUEORZRLO,QDZRUVWFDVHVFHQDULR ZKHUHSUREOHPDWLFSLVWRQULQJRUF\OLQGHUFRQGLWLRQVPD\H[LVWWKHSUHV - sure can actually overcome what the breathers can handle and cause gaskets to blow-out and begin leaking. (YHQLQDSHUIHFWZRUOGSUHFLVHO\PDFKLQHGSLVWRQVDQGULQJV¿WWR perfectly round and true cylinders would still result in a minute amount RIEORZE\VROHO\GXHWRWKHQHFHVVDU\VLGH D[LDO EDFNDQGHQGJDS FOHDUDQFH&OHDUDQFHPXVWQRWRQO\H[LVWLQWKHUHDUDQGVLGHVVRWKDW the rings remain free to turn within the ring lands, but also at the end gaps so that the ring ends do not butt together. This is the primary UHDVRQWKDWLWLVGLI¿FXOWWRHOLPLQDWHEORZE\VLPSO\EHFDXVHWKHUHDUH three leak paths for the combustion gases to follow. Not only can the gases leak between the top compression ring’s end gap and between the cylinder and face of the rings, but they can also leak between the back of the rings and ring lands. These facts illustrate the critical func- tion and importance of the top compression ring, to simply and effec- tively seal combustion pressure. It’s important to note that although the second ring is referred to as a compression ring, it’s function is solely as DVFUDSHUSUHYHQWLQJH[FHVVRLOIURPUHDFKLQJWKHWRSULQJDQGWKHUHE\ compromising its sealing ability. Another crucial factor, piston ring end gap is set so that when the engine is up and running at normal operating temperatures, it should WKHRUHWLFDOO\EHFRPHQHJOLJLEOH\HWVXI¿FLHQWWRSUHYHQWWKHHQGVIURP butting together. If at any time the rings have butted together, they will KDYHDVKLQ\DSSHDUDQFHWKDWLVHYLGHQWGXULQJWHDUGRZQ([WUHPH cases of end gap butting can cause the rings to bind in the cylinders, damaging the rings, pistons, and cylinder bores. Similar, binding condi- WLRQVFDQRFFXULIWKHULQJVKDYHLQVXI¿FLHQWVLGHRUEDFNFOHDUDQFH :KLOHH[FHVVLYHEORZE\FDQEHFDXVHGE\SLVWRQVDQGULQJVWKDW are simply worn-out or were improperly prepped during a prior rebuild, detonation, overheating or a lack of lubrication can be culprits as well, quickly destroying an otherwise perfectly good set of components. After literally millions of cycles, pistons, rings and the cylinders gradually
wear, causing clearances to grow, thereby creating a larger leak path for combustion gases. Detonation, also known as pre-ignition, caused by running too much ignition advance or operating an engine that is precar- iously lean, can quickly harm the pistons and rings, immediately com- promising ring seal. The pistons, rings, and cylinders can be damaged if WKHHQJLQHLVRYHUKHDWHGDVZHOO([FHVVLYHKHDWH[SDQVLRQHIIHFWLYHO\ WLJKWHQVSLVWRQWRERUHFOHDUDQFHFDXVLQJSLVWRQVFXI¿QJULQJELQGLQJ and end butting, all of which compromises cylinder integrity. Lack of lu- EULFDWLRQFDQDGGLWLRQDOO\FDXVHSLVWRQVFXI¿QJHIIHFWLYHO\KDUPLQJWKH pistons, rings, and cylinder bores, and can eventually lead to seizing. Although blow-by is a direct result of the combustion process and is impossible to eliminate, efforts should be made to keep it as minimal as possible, since any gases that leak past the rings are a cause for lost horsepower. Minimizing blow-by can be accomplished by using a set RISUHPLXPSUHFLVLRQPDFKLQHGSLVWRQV¿WWRH[WUHPHO\URXQGDQGWUXH cylinders that have been honed with a deck plate in place. The pistons VKRXOGEH¿WZLWKULQJVWKDWDUHFRUUHFWO\VL]HGDQGHQGJDSSHGIRUWKH VSHFL¿FDSSOLFDWLRQ7KHULQJVVKRXOGEHFDUHIXOO\FKHFNHGHQVXULQJ that each includes the proper width and radial wall thickness, verifying that they are truly compatible with the chosen pistons. Always carefully follow the piston ring manufacturer’s recommendations regarding bore SUHSULQJ¿WWLQJDQGHQGJDSVSHFL¿FDWLRQV 5DFLQJHQJLQHV¿WZLWKIXOOOHQJWKH[KDXVWKHDGHUVPD\EHDIIRUGDEO\ ¿WWHGZLWKDFUDQNFDVHHYDFXDWLRQV\VWHPWRKHOSDOOHYLDWHFUDQNFDVH pressure. Available from manufacturer’s including Allstar Performance $// WKHXQLWXVHVEUHDWKHUVSDLUHGZLWKYDFXXPFKHFNYDOYHVWR reduce crankcase pressure, eliminate oil leaks, and improve ring seal, thereby increasing engine performance. The most effective method in reducing crankcase pressure, however, is by employing a racing vacuum pump. Offered by manufacturers including CVR and Moroso, a vacuum pump uses negative air pressure to pull air out of the crank- case, creating vacuum. When selecting a pump, it is important that the chosen unit is sized correctly, plumbed, and geared to suit the chosen engine’s requirements. While it’s theoretically impossible to eradicate blow-by, sticking to the basics by selecting high-quality pistons and rings, ensuring that the cylinder bores have been properly honed, and remaining steadfast that the engine isn’t abused will pay dividends in not only preventing any measurable amount of blow-by, but keeping horsepower aplenty.
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