[Land-speed] Oiling

[John Burk]

My pocket calculator just told me some things I didn't know about getting oil
from the main bearings to the rod bearings at higher rpm .

Using the formula for centrifugal force .00034 x weight (lb) x radius (ft) x
rpm squared

The weight of motor oil .0318 # / ci  ( 7.34 # / gal div. by 231 )

The radius .115 ft of a BBC main bearing of .  ( half of 2.75" div. by 12 )

The radius .248 ft from the axis to the outside of the rod journal of a 427
bbc  (half of 3.76" + 1.1 div. by 12 )

So at 7500 rpm it takes 70 psi to just push the oil to the center of the crank
but centrifugal force adds 154 psi at the rod bearing . My 427 bbc dragster
worked fine at 7500 rpm with 60 psi oil pressure so outward flow must have
sucked the oil in to the center of the crank . I wonder if some combination of
stroke , main journal dia , oil press and temp and rpm , rod bearing problems
might not come from oil vaporizing at the crank axis , especially with fuel on
the oil . Does anybody know the vapor pressure of motor oil at 200 deg .