Page 338
REPAIR INSTRUCTIONS, PART 1
Electronic Unit Pump (EUP)
Installation
[221 GP]
TAPPET INSTALLATION
1. If not previously done, inspect each EUP
mounting screw hole in the engine block for
rusty or damaged threads. Clean or tap the
block screw holes to remove any rust or dirt
as required. Use an M10 x 1.5 bottom tap.
2. Clean the cylinder block at the pump
mounting surface and bores, if required.
Use only a soft rag and solvent to clean the
cylinder block. Minor fretting at the EUP mounting
surface is acceptable.
3. Submerge the roller tappets into a container
of clean engine oil to allow oil to fill the
passages to the roller axles. Remove each
tappet and while holding it vertically, spin the
roller to make sure the oil flows to the
surfaces between the axle and roller. This
step is important to provide adequate
break-in of the axle and roller at initial
start-up of the engine.
4. Carefully install each roller tappet into the
bore, pushing it down until it contacts the
camshaft lobe. The slot in the roller tappet
MUST be oriented outward to align with the
pin in the bore. Once installed, the roller
tappet should slide freely in the bore.
The tappet guide pins in the EUP bores are
factory-installed in all cylinder blocks and should
not be removed unless damaged.
PUMP INSTALLATION
1. Install new O-rings on each of the EUP
assemblies.
For engines with a history of fuel leakage into the
crankcase, a new delta seal O-ring (Figure 396)
is available through the MACK Parts System.
This seal should be used in the lower O-ring
position when necessary to correct leakage.
396
Figure 396 — EUP with Delta Seal O-Ring
2. Generously lubricate the EUP O-rings with
clean engine oil and install the No. 1 EUP
into the cylinder block (Figure 397).
Oil above the top O-ring should be kept to a
minimum to avoid weepage of excess oil (trapped
above the top O-ring) onto the cylinder block.
5-111.bk Page 338 Monday, July 10, 2006 2:26 PM
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