SPARK-TIMING

NZ Truth, Issue 1204, 27 December 1928, Page 13

SPARK -TIMING

Do It On Open Highway

Like carburettor adjusting, spark timing should be done out on the open road, and not m the servioe station. This is particularly true of encjines with higher compression ratios. . TIMING has to be very much more . accurate with -. high compression. Since a motor can be timed- faster as it runs faster the only -thing to do is to go out' on the road' and set the spark to match the speed you ordinarily Indulge Spark is not set so far advanced' for the new motors as for the older type. For instance, In one' engine the fully advanced spark comes when a piston has only ten thousandths of an Inch further to rise before fully compressing its. gas charge, This is rather difficult tq measure with ordinary means, which explains why service men. advocate going out on the road for the q.uickes« j and more practical results.