Manual

14
 


 
 
 

 



 




NOTES
Oiling systems in stock 1973 and later engines have two distinct dierences from earlier engines. Oil supplies to top end and bottom end are separated,

and connecting rod bearings receive constant oil supply through pinion shaft rather than intermittent supply as in earlier engines. Oil supply is separated
so tappets/heads get oil rst at highest possible pressure. In applications where hydraulic tappets are used, this system maintains high oil pressure to
tappets assuring proper operation. After top end components are satised, pressure relief valve opens allowing oil to ow to bottom end bearings and
other components. After bottom end is satised, relief valve opens further allowing excess oil to ow to incoming oil supply passage side of pump.
Separate oil supply delivered to bottom end allows change in delivery at pinion shaft from intermittent to constant feed system, hence, end oiling style
pinion shaft. S&S® recommends separating oil supply in generator style cases when hydraulic tappets are used. This is possible only if S&S 31-6250 style
replacement oil pump is used. If stock, cast iron or early alloy pump is used, oil supply cannot be separated and pinion shaft must not be converted to
constant oil feed.
Using stock cast iron oil pump or 1968-1969 alloy pump with constant feed pinion shaft oiling system can result in abnormally low oil
pressure with possible engine damage as a result.
If stock alloy pump is used, proper identication to conrm it is correct type is imperative. Dierent year alloy pumps have design changes that could

interfere with oil circulation if used with wrong style crankcases. Some early stock alloy pumps will also cause pressure relief passage in S&S crankcase
to be uncovered, resulting in large oil leak.
Pump and other parts such as pinion shaft and pinion shaft bushings, rocker shafts and rocker shaft bushings, lifters and lifter guides must be serviceable

and in good condition to insure proper oil pressure and circulation.
Insucient oil supply may result in premature wear or damage to critical engine components.
 See Pictures 4 & 5.
 
 
 

 
 
 
 

 

 

        

 


 
CAUTION
CAUTION