EL-740 Air Compressor Specifications

EL-740 Air Compressor

Type – Two cylinder

Rating – 7.4 cubic feet per minute

Cylinder Head Components

Exhaust valve seat top of valve seat to seating surface – 3.18 to 3.25 mm (.125 to .128 in)

Exhaust Valve Cage:

Overall length – 22.66 to 22.76 mm (.892 to .896 in)

Valve stop surface to spring seat surface – 18.29 to 18.80 mm (.720 to .740 in)

Piston And Connecting Rod Components

Pistons:

Piston diameter (standard) – 50.66 to 50.69 mm (1.995 to 1.996 in)

Piston diameter 0.25 mm (.010 oversize) – 50.91 to 50.94 mm (2.005 to 2.006 in)

Piston diameter 0.50 mm (.020 oversize) – 51.17 to 51.19 mm (2.015 to 2.016 in)

Piston pin hole diameter – 12.586 to 12.695 mm (.4955 to .4998 in)

Connecting Rod:

Piston pin hole diameter – 12.705 to 12.710 mm (.5002 to .5004 in)

Piston Pin:

Piston pin diameter – 12.695 to 12.700 mm (.4998 to .5000 in)

Piston Rings:

Compression ring gap in 2.000 inch bore – 0.127 to 0.254 mm (.0050 to .0100 in)

Oil ring gap in 2.000 inch bore – 0.254 to 1.016 mm (.0100 to .0400 in)

Groove to ring clearance:

Air Compressor rings – 0.127 to 0.762 mm (.0050 to .0300 in)

Oil rings – 0.0127 to 0.1270 mm (.00050 to .00500 in)

Cylinder Block

Cylinder bore diameter (Standard) – 50.787 to 50.800 mm (1.9995 to 2.0000 in)

Cylinder bore diameter 0.25 mm (.010 Oversize) – 51.041 to 51.054 mm (2.0095 to 2.0100 in)

Cylinder bore diameter 0.50 mm (.020 Oversize) – 51.295 to 51.308 mm (2.0195 to 2.0200 in)

Crankshaft

Connecting Rod Journal Diameter:

Standard – 28.524 to 28.537 mm (1.1230 to 1.1235 in)

0.25 mm (.010 in) Undersize – 28.270 to 28.283 mm (1.1130 to 1.1135 in)

0.50 mm (.020 in) Undersize – 28.016 to 28.029 mm (1.1030 to 1.1035 in)

0.75 mm (.030 in) Undersize – 27.762 to 27.775 mm (1.0930 to 1.0935 in)

Connecting rod journal width – 25.40 to 25.451 mm (1.000 to 1.002 in)

Main bearing journal diameter – 34.999 to 35.011 mm (1.3779 to 1.3784 in)

Air Compressor Governor

Cut-out pressure setting – 827 to 861 kPa (120 to 125 psi)

Cut-in pressure setting – 710 to 737 kpa (103 to 107 psi)

Crankcase

Bearing Bore Diameters:

Cast Iron – 71.99 to 72.01 mm (2.834 to 2.835 in)

Aluminum – 71.96 to 71.98 mm (2.833 to 2.834 in)

Bearing Cap

Bearing Bore Diameter – 35.04 to 35.08 mm (1.380 to 1.381 in)

Ball Bearing

Outside Diameter – 71.99 to 72.00 mm (2.834 to 2.835 in)

Inside Diameter – 34.99 to 35.00 mm (1.378 to 1.378 in)

Unloader Pin

Pin Length – 32.51 to 32.77 mm (1.280 to 1.290 in)

Pin Length – 48.64 to 48.90 mm (1.915 to 1.925 in)

Pin Length – 54.18 to 54.43 mm (2.133 to 2.143 in)

NOTE: Pin length required is determined by the combination of cylinder head and unloader assembly used.