Milodon Chrysler Aluminum Hemi & Wedge Oil Pump 21815 - Manual

MILODON
2250 Agate Court
Simi Valley, Ca 93065
(805) 577-5950
Chrysler 383-440 Wedge and 426 Hemi Oil Pump
#21815
This oil pump is the same as used by the Hemi Pro Stock cars when they dominated the ranks
and the same as used in Top Fuel cars such as Frank Bradley's and Dick LaHaie's. It will easily
pump 19 G.P.M. of oil while using less horsepower to drive it than many other styles of pump.
Like many other trick pieces it only requires a little care when installing to give many years of
flawless performance. There are certain problems that may occur upon installation in block that
can cause serious damage to the oil pump and should be checked before the engine is fired.
1. We have found on some blocks (both steel & aluminum) misalignment between the pump
mounting holes in the block and the holes thru the pump. When bolts are tightened the pump
will distort causing interference between the housing and gears. If this occurs, pump and
cover bolt holes may be drilled over size within reason to compensate for misalignment.
2. On some blocks (both steel & aluminum) pump pad is machined at wrong angle causing
pump to not sit square against pad and when bolted up will distort pump housing and perhaps
crack the pump neck. If this occurs, block pump pad should be re-machined on correct angle
(90 degree to pump neck hole).
3. Length of distributor drive shaft should always be checked to be sure that shaft is not
bottoming out in gear causing this gear to dig into and ruin the pump cover. A minimum of
.060" shaft end clearance is required. Shaft should be shortened if neccessary. The Milodon
#21513 and #21523 pump shafts are required by the 21815 pump equipped engines. When a
steel bodied high volume pump is used, the 21505 and 21525 pump shaft and gears are
reuired. When a steel bodied high volume pump is used with a dual line spacer the long length
pump shaft #21500 and 21520 are required.
4. Before priming the pump initially, a liberal coating of white grease, or the like, should be
applied to the inside of the pump housing and all gear surfaces. This will prevent dry start up
scoring and will allow immediate priming of the oil system. For initial system priming
Milodon's 23015 shaft should be used. To assist the pump to prime on initial start-up, as the
rear inlet line enters the oil pump route it slightly above the oil pump before it turns down to
the pick-up.
5. This pump is required to pull usually cold oil through two 7/8" I.D. lines as opposed to a
stock system's 1/2" I.D. passageway, so it may react a little slower. Because it has a tougher
job, any gear scoring due to foreign debris will start to inhibit the pumps priming ability. The
oil filter will catch this debris but only after going through the gears! Replacement gear sets
for this pump are Milodon part #21817. Pump O-ring and gasket rebuild kit is Milodon part
#21590. Externally adjustable pressure regulator is Milodon part #21550. NOTE: 21815
does NOT use the stock Chrys o-ring around the gear.