Adjusting The Dwell Angle On The Spark Distributor Of An Engine
| Field | Automotive Repair and Service |
| Went Obsolete | Depends on your point of view... 1987 Hyundai Pony still had breaker points... Some folks like old cars that still use breaker points (but many at least upgrade to an electronic distributor) |
| Made Obsolete By | Advancements in Electronic Engine Controls and advanced ignition systems |
| Knowledge Assumed | Ability to read a dwell meter, to use hand tools, an understanding of the system at hand |
| When useful | Replacing points, troubleshooting a poorly-running engine, when performing a tune-up, when stuck at the side of the road because the points had burned and the engine will no longer run... |
Adjusting dwell allowed the breaker points of an ignition distributor to remain closed long enough to permit the ignition coil to fully saturate (i.e. allow the current through the coil to reach its maximum) to create the longest spark.
This required patience, skill, determination and the ability to read a dwell meter or the ability to set the point gap with feeler gage. (An excellent write-up is here: http://home.earthlink.net/~goodspeeds/POINTS.HTM(approve sites). Dwell varied according to the number of engine cylinders and is related to breaker point gap.
Dwell and point gap changed as the friction components of the distributor (the rubbing block of the points and the point cams) would wear.
Dwell and point gap would change as the engine ran, so periodic adjustment would be required even between point replacement.