Page 171 - 2019-2020 Racecar Engineering Circle Track Parts and Accessories Catalog

High-Performance Oil Pumps
GM LS Series High-Volume/ 1HZ LURQ DOOR\ SXPSV DUH FDVW ZLWK
High-Performance Oil Pump By Schumanns less porosity for a yield strength of 70,000
*0 /6 6HULHV RLO SXPS LV HQJL- PSI. Pumps are blueprinted and precisely
neered for applications with up to PDFKLQHG ZLWK IXOO ÀRZ VKDIW RLOLQJ H[DFW PHVK
500 horsepower and includes an JHDUV DQG DQWL DHUDWLRQ EOHHG RII IRU H[FHSWLRQ-
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block with an O-ring seal. Pump ³6SRUWVPDQ 665´ VHULHV LQFOXGH
additionally features machined and DQG 36, SUHVVXUH UHOLHI VSULQJV
radiused internal oil passages for in- O.E. Sportsman
FUHDVHG RLO ÀRZ 6ROG FRPSOHWH ZLWK WKUHH Description Plus SSR
color-coded pressure relief springs in 60, Small Block Chevy 262-400
DQG 36, UDWLQJV Standard Volume AFM20315 AFM20317*
High Volume AFM20316 AFM20318*
Part No. Description High Volume, Quick Change Relief Spring — AFM20319* †
AFM20330 GM LS Series Oil Pump Standard Volume, 3/4" Pickup AFM20320 —
AFM20331 GM LS Oil Pump-To-Crank Center Alignment Tool Kit, High Volume, 3/4" Pickup AFM20322 —
Aids Pump Installation
Small Block Ford 289-351W
Standard Volume AFM20323 —
AFM20314
SB Chevy Oil Pump High Volume AFM20324 AFM20325 ‡
Pressure Relief Springs * Includes additional relief springs
6SULQJV ¿W $)0 +LJK 3HUIRUPDQFH 2LO 3XPSV AFM20313 † Includes anti-cavitation plate
‡ Gear pressure balanced to prevent hydraulicing
Part No. Description
AFM20313 Pressure Relief Spring, 65-70 PSI
AFM20314 Pressure Relief Spring, 80-90 PSI

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 wear, causing clearances to grow, thereby creating a larger leak path for
every internal combustion engine, regardless of brand, builder, or bud- combustion gases. Detonation, also known as pre-ignition, caused by
get, is subjected to it. Blow-by, also referred to as crankcase pressure, running too much ignition advance or operating an engine that is precar-
occurs during the combustion process when burned gases leak past the iously lean, can quickly harm the pistons and rings, immediately com-
piston rings and into the crankcase. The rotation and speed of the rotat- promising ring seal. The pistons, rings, and cylinders can be damaged if
ing assembly, which not only cause windage, contributes to crankcase WKH HQJLQH LV RYHUKHDWHG DV ZHOO ([FHVVLYH KHDW H[SDQVLRQ HIIHFWLYHO\
pressure, as well. WLJKWHQV SLVWRQ WR ERUH FOHDUDQFH FDXVLQJ SLVWRQ VFXI¿QJ ULQJ ELQGLQJ
Crankcase pressure is released through the breathers, even to the and end butting, all of which compromises cylinder integrity. Lack of lu-
H[WHQW RI FDXVLQJ WKHP WR GULS RU EORZ RLO ,Q D ZRUVW FDVH VFHQDULR EULFDWLRQ FDQ DGGLWLRQDOO\ FDXVH SLVWRQ VFXI¿QJ HIIHFWLYHO\ KDUPLQJ WKH
ZKHUH SUREOHPDWLF SLVWRQ ULQJ RU F\OLQGHU FRQGLWLRQV PD\ H[LVW WKH SUHV- pistons, rings, and cylinder bores, and can eventually lead to seizing.
sure can actually overcome what the breathers can handle and cause Although blow-by is a direct result of the combustion process and is
gaskets to blow-out and begin leaking. impossible to eliminate, efforts should be made to keep it as minimal as
(YHQ LQ D SHUIHFW ZRUOG SUHFLVHO\ PDFKLQHG SLVWRQV DQG ULQJV ¿W WR possible, since any gases that leak past the rings are a cause for lost
perfectly round and true cylinders would still result in a minute amount horsepower. Minimizing blow-by can be accomplished by using a set
RI EORZ E\ VROHO\ GXH WR WKH QHFHVVDU\ VLGH D[LDO EDFN DQG HQG JDS RI SUHPLXP SUHFLVLRQ PDFKLQHG SLVWRQV ¿W WR H[WUHPHO\ URXQG DQG WUXH
FOHDUDQFH &OHDUDQFH PXVW QRW RQO\ H[LVW LQ WKH UHDU DQG VLGHV VR WKDW cylinders that have been honed with a deck plate in place. The pistons
the rings remain free to turn within the ring lands, but also at the end VKRXOG EH ¿W ZLWK ULQJV WKDW DUH FRUUHFWO\ VL]HG DQG HQG JDSSHG IRU WKH
gaps so that the ring ends do not butt together. This is the primary VSHFL¿F DSSOLFDWLRQ 7KH ULQJV VKRXOG EH FDUHIXOO\ FKHFNHG HQVXULQJ
UHDVRQ WKDW LW LV GLI¿FXOW WR HOLPLQDWH EORZ E\ VLPSO\ EHFDXVH WKHUH DUH that each includes the proper width and radial wall thickness, verifying
three leak paths for the combustion gases to follow. Not only can the that they are truly compatible with the chosen pistons. Always carefully
gases leak between the top compression ring’s end gap and between follow the piston ring manufacturer’s recommendations regarding bore
the cylinder and face of the rings, but they can also leak between the SUHS ULQJ ¿WWLQJ DQG HQG JDS VSHFL¿FDWLRQV
back of the rings and ring lands. These facts illustrate the critical func- 5DFLQJ HQJLQHV ¿W ZLWK IXOO OHQJWK H[KDXVW KHDGHUV PD\ EH DIIRUGDEO\
tion and importance of the top compression ring, to simply and effec- ¿WWHG ZLWK D FUDQNFDVH HYDFXDWLRQ V\VWHP WR KHOS DOOHYLDWH FUDQNFDVH
tively seal combustion pressure. It’s important to note that although the pressure. Available from manufacturer’s including Allstar Performance
second ring is referred to as a compression ring, it’s function is solely as $// WKH XQLW XVHV EUHDWKHUV SDLUHG ZLWK YDFXXP FKHFN YDOYHV WR
D VFUDSHU SUHYHQWLQJ H[FHVV RLO IURP UHDFKLQJ WKH WRS ULQJ DQG WKHUHE\ reduce crankcase pressure, eliminate oil leaks, and improve ring seal,
compromising its sealing ability. thereby increasing engine performance. The most effective method
Another crucial factor, piston ring end gap is set so that when the in reducing crankcase pressure, however, is by employing a racing
engine is up and running at normal operating temperatures, it should vacuum pump. Offered by manufacturers including CVR and Moroso, a
WKHRUHWLFDOO\ EHFRPH QHJOLJLEOH \HW VXI¿FLHQW WR SUHYHQW WKH HQGV IURP vacuum pump uses negative air pressure to pull air out of the crank-
butting together. If at any time the rings have butted together, they will case, creating vacuum. When selecting a pump, it is important that the
KDYH D VKLQ\ DSSHDUDQFH WKDW LV HYLGHQW GXULQJ WHDU GRZQ ([WUHPH chosen unit is sized correctly, plumbed, and geared to suit the chosen
cases of end gap butting can cause the rings to bind in the cylinders, engine’s requirements.
damaging the rings, pistons, and cylinder bores. Similar, binding condi- While it’s theoretically impossible to eradicate blow-by, sticking to the
WLRQV FDQ RFFXU LI WKH ULQJV KDYH LQVXI¿FLHQW VLGH RU EDFN FOHDUDQFH basics by selecting high-quality pistons and rings, ensuring that the
:KLOH H[FHVVLYH EORZ E\ FDQ EH FDXVHG E\ SLVWRQV DQG ULQJV WKDW cylinder bores have been properly honed, and remaining steadfast that
are simply worn-out or were improperly prepped during a prior rebuild, the engine isn’t abused will pay dividends in not only preventing any
detonation, overheating or a lack of lubrication can be culprits as well, measurable amount of blow-by, but keeping horsepower aplenty.
quickly destroying an otherwise perfectly good set of components. After
literally millions of cycles, pistons, rings and the cylinders gradually
2019-20 CIRCLE TRACK PARTS AND ACCESSORIES 167