1956 AMC Hudson Technical Service Manual Supplement

ENGINE V-8 15
are lubricated from the center longitudinal oil gallery. Holes
drilled in the crankshaft throws afford lubrication to the
connecting rod bearings. Low speed cylinder wall lubrication
is obtained through small holes or channels in the
parting surface of the connecting rod and bearing caps.
Throw-off oil from the connecting rods lubricates camshaft
lobes and cylinder walls at higher speeds.
Passages at the front of the engine (Fig. 27) and in the
camshaft thrust plate (Fig. 11) connect the main center oil
gallery with the two (left and right) oil galleries to the
hydraulic valve tappets.
At the rear section of each tappet oil gallery, a passage
connects upward to the rear rocker arm shaft support retaining
bolt hole. These bolts are drilled to permit oil flow to the
rocker arm shafts, rocker arms, push rods, valve stems, and
valve guides.
Two drain holes in the lower corners of the cylinder head
casting return the oil to the oil pan.
1. Oil Pump Drive Shaft 8. Driven Gear
2. Key 9. Cover to Body Gasket
3. Pump Mounting Gasket 10. Cover
4. Body 11. "0" Seal Ring
5. Relief Valve Plunger 12. Inlet Tube and Screen
6. Relief Valve Spring Assembly
7. Drive Gear
Oil Pressure Relief Valve
FIGURE 25—Oil Pump Assembly
The oil pressure relief valve is not adjustable. A setting of
55-60 pounds pressure is built into the tension of the spring.
On the released position, the valve permits oil to by-pass
through ports and a passage in the pump cover to the inlet
side of the pump.
Lubrication Circuit
Oil drawn through the inlet screen and tube assembly is
displaced into the pressure discharge side of pump to a port
indexing with a vertical oil gallery up into the cylinder
block where it indexes with a horizontal passage leading to
the lower oil filter mounting adapter (Figs. 20 and 26).
Oil is returned from the oil filter to the timing chain
compartment. All camshaft and main crank-shaft bearings
ENGINE SPECIFICATIONS
Bore 3-1/2"
stroke 3-1/4"
Displacement 250 Cu. In.
Compression Ratio 8.0:1
carburetor
WGD—Twin-Throat
Brake Horsepower 190 @ 4900 R.P.M.
Torque
240 Ft. Lbs. @
2000-3000 R.P.M.
Taxable Horsepower 39.2
Piston Displacement 250 Cu. In.
Valve Timing
Intake
Opens 12° 30' B.T.D.C.) 244°
Closes
51° 30' A.B.D.C.) Duration
PISTONS AND RINGS
Piston to Bore Clearance
Top Land .020"-.024"
Skirt Top .001"-.0015"
Skirt Bottom .0009"-.0015"
Piston Ring Gap Clearance
Top .010"-.020"
Center .010"-.020"
Bottom (Steel Rail) .015"-.055"
Piston Ring Side Clearance
Top .002"-.0035"
Center .002"-.004"
Bottom .001"-.0079"
Piston Pin to Connecting Rod Press Fit
Piston Pin to Piston
Palm Press Fit in
Piston at Room
Temperature