POWER LOSS.

Auckland Star, Volume LXVII, Issue 71, 24 March 1936, Page 18

POWER LOSS.

POINTS TO BE WATCHED,

VALVES AND IGNITION.

The process of wear is gradual. Tlie engine loses power little by little until suddenly tlio driver realises that it is not pulling so well —that it does not go up hills with such a verve as it used to, and that more frequent gear changing is needed. Sudden loss of power may also develop, and in either case tlie remedy can bo sought for and probably found from one of the following causes: Ignition trouble; l.oss of compression; valves; poor carburet ion; need for decarbonising. Hie causes of overheating are usually air leaks due to sticky valves and bad joints, fan and cooling not working properly, ignition retarded and shortage of engine oil, all of which may, owing to the overheating, affect the power' output of tlie engine. These points should be checked. Amplifying tlio causes., of loss of power, the following points should be investigated. Valves. — Weak springs may not return the valves quickly enough to their seats; after prolonged the springs may need replacement. Valve clearance incorrect, insufficient causing the valves to remain unseated when the engine is warm, and too much giving insufficient lift to admit a full charge of mixture. Theso may be of the direct outcome of wear plus lack of attention.

Piston Rings. —If sticking in their grooves, or conversely, if loose in worn grooves, will allow gas leakage to occur. Ono symptom of piston trouble is the emanation of fumes in quantities from the crankcase breather.

Worn Cylinders.—Allowing leakage of gas past the pistons combined with the weakening effect of mixture witli air which may enter the combustion, chamber in the reverse direction. Cylinder,, ring and valve troubles have serious effects upon the compression, which is reflected in the power output of the engine.

Ignition Faults. —May include dirty distributor points; carbon fouling the magneto distributor; dirty plugs or wrong gap (which should be .OlSin with magneto and .020 in with coil); connections loose; short circuiting across coil terminals duo to dirt. In the distributor look for sticky rocker arm, broken spring or insufficient spring tension.

Exhaust Box.—lt is possible that carbon may have built up in the exhaust system, causing back-pressure.

Decarbonise.—lf the engine has not been -touched for some time and tends to knock under load. At tlie same time, regrind the valves, clean ports and check plug settings.