John, I think the water injection on old tractors was to compensate for poor quality gasoline or kerosene. Don Actually with 4:1 compression in 1915 or so, there was no poor quality gasoline or kerosene per say, it was the best stuff they had at the time and it ran sort of ok. Water injection though was used to stop detonation which could be induced by improper setting of the timing and other variables such as improper mixture etc. etc. when the engine was loaded or under power. Remember, these things were set manually in many cases or under poor automatic control due to early design limitations. The point is, change your times, add some boost, raise the compression, change the gasoline or increase the altitude, and the basic function is still there, it is used to eliminate knocking taking place in the combustion chamber of an engine and has been around for about 100 years. At any given "power" setting you will increase power if you are eliminating the "knock" caused by detonation or early ignition timing thus saving the engine and increase the capability of developing higher power. Of course if you are increasing power, it stands to reason that you could be wearing out the engine faster which is why a 500 cubic inch AA Fuel Dragster developing upwards of 5000+ horsepower has a life span that can be measured in min. rather than in thousands of miles. Timing was adjusted by listening for knock under given conditions and then moving the timing control usually on the steering wheel until the audible knocking sound disappeared. This type of control was used well into the 30's before the advent of automatic control of timing. In the crudest form and under given circumstances, timing was used to adjust the speed of the engine, retard timing to slow it down and advance timing to speed it up. Of course this was used under a very narrow set of circumstances but some engines such as out board motors this was till done up into the 40's. To change speed, you re-set the timing and adjusted the main metering jet to optimize the running of the engine. There was no throttle butterfly in the carburetor to do this with. John. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.amc-list.com/pipermail/amc-list/attachments/20070803/3f0a7128/attachment.htm _______________________________________________ Amc-list mailing list Amc-list@xxxxxxxxxxxx http://www.amc-list.com/mailman/listinfo/amc-list