NURSE YOUR DIESEL

Lake County Mail, Issue 12, 13 August 1947, Page 11

NURSE YOUR DIESEL

Care is Cheaper than Spares

In previous issues the writer has stressed the necessity of care, and in ensuring l always the necessity of using only clean fuel, and the methods to employ to safeguard against dirt clogging the delicate fuel feed system.

If you have a problem, forward it to “Ariel,” c/o P.O. Box 434, Dunedin.

This week the injection system and combustion is to receive our attention.

The fuel flows from the tank to the Alter and thence to the transfer pump to wait until one of the injection pump plungers which is pulled down by the return spring encounters the port in the cylinder and allows the fuel to flow in and fill the space above the plunger. The cam then forces the plunger upwards, closes the port, and as fuel is virtually incompressible, forces open •.the discharge valve and pushes the small column of fuel through the fuel •4>ipe to the injector on the cylinder which is due to fire. The fuel now tries to lift the pintle in the nozzle until sufficient pressure is built up to accomplish this. When the fuel issues in a fine spray into the swirling, heated turbulence of compressed air in the cylinder it ignites and combines with the oxygen in the cylinder, superheats and expands, pushing the piston down on the power stroke until at a point determined by the governor and throttle setting the cut-off slot in the injector pump plunger then uncovers the port in the injection pump cylinder communicating with the fuel supply and the pressure being relieved the pintle in the injection nozzle is forced by its return spring on to its seat and the spray of fuel in the cylinder ceases. Combustion continues in the cylinder until all the fuel delivered by the spray, or all the oxygen, or both are exhausted. At low power setting the fuel is sufficient to combine with only a por-

Points to Watch in the Injection System

1. Cleanliness of fuel

General Tractor Attention

tion of the oxygen present at medium power, say half, and at full power all of the oxygen. Should the spray continue past this point, the balance of fuel delivered is wasted and passes as fuel vapour with the exhaust gases.

2. Solid fuel line by keeping tank full and cock to fuel line open. Should air be present in say one fuel line it will pass through the pump and 'cause the injector to cease to function. To relieve this, if no provision is made to bleed air, slacken the fuel line union at the injector about i to 4 turn until solid fuel is being pumped out, tighten again and that injector should pick up its duties. Repeat with each .injector after which the engine should be running smoothly if everything else is in order.

3. Keep oil level correct in injection pump casing.

4. Pardon the repitition, but keep those filters clean.

Spare a few minutes each day to tighten any slack nuts as loose nuts mean play, worn threads, lost bolts, broken castings, annoying delays and expense. With a little regular attention your tractor will retain its youth and ability to give you trouble-free service. (To be Continued.)