Monte gave this some thought, and i dont see any reason why youd adjust the timing plus or minus based on gvw. the timing is set so that the fuel is being delivered to the enigne at the most opportune moment for the most complete utilization and combustion of the available fuel, making the engine as efficient as possible. if anything, id think the greater the gvw, the closer you would want to be to the factory determined 8* btdc, as you will need the engine to be running as efficiently as possible to accomodate the additional load to the vehicle. only time i could think that youd want to go one way or another adjusting timing would be if something else was being added to the system such as boost, propane, water/methanol, veggie oil, or something like that were the combustion process is going to be slower or faster based upon whats being added, and even then i dont think it would be best course of action, as it would only be a fix to keep some other issue from occuring (ie pinging, stress on head bolts, etc). again, these are just guesses, please correct if im wrong here people, just tossing ideas out based on what little i know about the way these engines work.
wat he said
