NURSE YOUR DIESEL

Lake County Mail, Issue 14, 27 August 1947, Page 11

NURSE YOUR DIESEL

Care is Cheaper than Spares

In previous chapters, the writer has confined himself to general hints and warnings. This series has been inaugurated for your benefit, so if you have a problem just write in to “Ariel,” Box 434, Dunedin.

This week we anticipate a few questions and provide the answers: 1. Should petrol be used either directly or through the air cleaner if starting is difficult? Definitely no, because the mixture of petrol and air is highly explosive, ignites at a low temperature, and, before compression is complete, will detonate (explode violently), impose severe strain on piston, con-rods, and crankshaft, etc., as compression will have to be completed against the resultant explosion pressure, a violent knock will be heard, or, under certain circumstances, the motor may back fire and run in the reverse direction, the reversal of stresses setting up considerable strain on flywheel mountings, etc. 2. Should the fuel cock at the tank be turned off when stopping? No, as air locks are likely to ensue and necessitate priming of the fuel system alb the way from fuel tank to injectors. Shut cock only when desiring to remove fuel pipes or pump. 3. What, is detergent lubricating oil? This term is applied to oil designed and produced to dissolve carl)on and permit longer operation between overhauls. 4. What happens if I change from ordinary lubricating oil to a detergent oil? An engine run on ordinary lubricating oil over a period becomes carboncd up in the combustion chamber on the head of the piston and behind the piston-rings; when a de-

tergent oil is now used, the carbon is dissolved, the worn rings are freed, compression drops, and starting and running may be affected in severe cases, and the overhaul, which was due in any case, be forced upon you. 5. White smoke is present all the time from the exhaust. What is the reason? The white smoke is excess lubricating oil, due to worn or gummedup rings, and if power is poor or starting difficult new rings or at least dccarbonisation and cleaning are required. fi. Black smoke is very noticeable bn starting or while running. What causes this? Starting: Black smoke is caused by excess fuel due to faulty injectors or one or more fuel pump units being wrongly engaged to the control rack operated by the governor, failure to start on the first attempt, and unvaporised fuel remaining in the cylinder and with subsequent charges from the injectors totalling more fuel than, the oxygen present can combine with, the excess appearing as black smoke if combustion occurs or like steam if ignition docs not take place. Black smoke while running; Improper or too much fuel being supplied. Hard starting may be caused by: (1) No fuel; (2) air locks between tank and injectors; (3) engine too cold — heat water; (4) weak batteries—recharge; (5) fuel too heavy to flow properly; (6) water in fuel; (7) rings ox eybuffer \von\ —replace. - , (8) valves need grinding; (9) faulty cylinder head gaskets; (10) air cleaner dirty.

f‘ Your uucle is very ill.” “ I am prepared for everything.” “Really! I thouglit you were only heir to half.”