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.

Categories: EL-740 | 1 comment

One Comment

  1. Bonjour, (English traduction, look down)

    une gros merci d’avoir fait l’effort de mettre toutes ces informations sur internet.

    Ça faisait plus de deux jours que je recherchais des informations pour, peut-être, réparer mon compresseur. Difficile lorsque les plaques d’identifications ne sont plus en place.
    Il s’agit, finalement, d’un compresseur EL-740.
    Il est installé en tant que compresseur de garage. “Home-made”.

    Lorsque j’ai enfin réussi à trouver vos informations, par le plus heureux des hasards, avec beaucoup de persévérance par contre, j’ai été vraiment heureux.

    Merci énormément.

    Il ne me restera qu’à savoir si je peux commander les pièces que j’ai besoin. J’espère être capable de les trouver.

    Salutation,
    Carl-Dave(Abitibi, Québec, Canada)
    —–traduction internet———–

    Hello,
    a big thank you for making the effort to put all this information on the internet.

    It had been more than two days since I was looking for information to maybe repair my compressor. Difficult when the identification plates are no longer in place.
    This is ultimately an EL-740 compressor.
    It is installed as a garage compressor. ‘Home-made’.

    When I finally managed to find your information, by the happiest of chances, with a lot of perseverance on the other hand, I was really happy.

    Thank you so much.

    It only remains for me to know if I can order the parts I need. I hope to be able to find them.

    Greeting,
    Carl-Dave (Abitibi, Quebec, Canada)

Leave a Reply

Required fields are marked *