THAT ENGINE NOISE

NZ Truth, Issue 1212, 21 February 1929, Page 18

THAT ENGINE NOISE

It Always Points The Way To Carbon Trouble

A sudden spurt to pass a sluggish street car — a clanking, ringing knock that sounds like distant cow bells; it's' the engine's warning noise that points to carbon. ..' ■' ,-'■■

BUT carbon is riot always present when this knock occurs. In modern high compression, high efficiency engines it means that maximum power is being obtained from the gas and that, with a slight retarding of spark; for heavy pulling, the same power can! be obtained— rminus the knock. In older cars the ringing sound may mean that worn pistons and cylinders no longer fit, and the excess clearance is permitting the piston skirt to slap against the cylinder wall at each explosion. Under such circumstances the cylinders should be reamed or honed larger and new oversize pistons, installed. But if excess carbon deposits are to blame, the car-owner can do the job himself, if he is rriech- ' anically inclined. ' , On L-head engines the work is simple, while on overhead types it necessitates disconnecting the intake and exhaust manifolds and readjusting the valves after the job has been completed. • : ' • It is, therefore, well for the carowner to study his instruction book and see what the work involves. It is usually found that the first thing to do is to drain out the water and remove the cylinder head bolts or nuts. ' There is also a water connection to be disconnected m «iost cases. The actual carbon scraping job is simple,

but there" are a number of precautions to be observed. •...'.; . ■ In removing the carbon, turn the en- ; gihe so that the valves near .the cylinder being ■worked, on are closed. ~ s This will keep carbon particles from, getting under the valves and affectingtheir fit on the seats. Then stuff rags m the water passages to keep out bits of carbon, and, if cap screws hold the head m place, replace these to keep , carbon out of the bolt holes. If the cylinder .head gasket has been damaged, a new one should be used, and when the gasket is -applied it should be spread with cup grease on both sides m order to effect a good, tight joint. . Some mechanics use shellac or gasket cement, but if this is done, it will be difficult to get the head off again. Grease, however, makes a tight joint, but one that does not interfere with taking the. head off at some future date. Many owners of new cars are. not comfortable m riding, due to change of positions m seats. Some later model cars have an adjustment to allow the seats to be moved backward or forward as desired. If this cannot be done, an upholsterer can stuff the seat. The seat can be made more comfortable by tipping the cushion up and placing a strip of wood under it to rest the legs.