S&S Cycle Sidewinder 3 5/8 Big Bore Cylinders for 1936–1999 Big Twins - Manual (Page 12)

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9. Cam, Lifters and Tappet Blocks (All)
NOTES:
• Big inch, stroked engines with compression ratios of 8.5:1 or more respond well to higher lift, longer duration cams. Engines with lower compression
ratios should have shorter duration cams. S&S® offers cams for all big twins, except the knuckleheads that we have run in our test engines. We
recommend their use along with S&S high performance valve springs and retainers. These components along with other valve train parts are
available in kits that not only satisfy most any degree of rebuilding required but also make valve spring spacing and high lift cam installation an
easy job. If you are using a high lift camshaft perform any required head work and valve spring spacing per manufacturer’s instructions.
• Sidewinder® built using knucklehead 1936–‘47 cases may use any aftermarket knucklehead cam such as an Andrews “S” or “K” grind. Knuckleheads
installed on later crankcases, 1948 and up, should use cams such as “575” Sifton. In panhead or shovelhead 575’s lift is much higher, but when used
with knuckleheads, lift is only .400” since knucklehead rocker arm ratio is 1:1.
• Sidewinder kits for Harley-Davdison® Evolution® engines have been tested using both solid lifters and hydraulics. We recommend using hydraulic
assemblies in all Evolution® applications. They are far superior to early style panhead/shovelhead assemblies and hold up extremely well under
most conditions. To maximize efficiency and reduce potential valve float in high rpm situations, S&S Hydraulic Lifter Limited Travel Kit should be
used in all late model performance applications.
• 1953 and later, panhead and shovelhead strokers with solid lifters should have tappet block hydraulic lifter oil feed holes plugged to prevent excess
oil escaping above lifters from filling pushrod tubes causing potential oil leaks.
To plug tappet block oil feed holes, perform following steps:
A. Starting at gasket surface end of oil feed passageway in tappet block base, thread 8-32 tap into oil passage hole. Turn tap until tap end just
starts to enter cam follower hole.
B. Screw 8-32 x 3⁄16" allen head set screw in passageway until it stops.
C. Perform steps A and B to other tappet block.
NOTE: If hydraulic lifters are ever reinstalled, plugs must be removed.
Restricted oil flow to hydraulic lifter assemblies causes lifters to operate with improper oil pressure which may damage them or other
valve train components.
10. Connecting Rod Preparation (All)
NOTE: If S&S® connecting rods are used, follow instructions that accompany rods since rod preparation below has already been done. See S&S big twin
rod information section on page 15.
If S&S rods are not used, perform following steps:
A. To insure adequate oil on sides of rods and matching thrust surfaces of flywheels, S&S recommends that four grooves be ground on each
side of both front and rear connecting rods. See Figure 4, below. Make these grooves .020" to .030" deep and .030" to .040" wide and
should be ground 90° from each other. After making grooves, remove all sharp edges and burrs with emery cloth.
B. With rods assembled, measure distance between rods at closest points in wristpin holes. If measurement exceeds 2.950" as shown in
Figure 4, below, grind female rod at points where male rod makes contact to achieve sufficient clearance.
CAUTION
Figure 4