Timing bump
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This also effects certain types of injectors, such as marine 370s, which have a wider angle of spray (155* versus street injectors of 145*) causing excess smoke and fuel consumption. Though it is possible to make more power, it is "dirty power" at a cost of excess smoke and wasted fuel, not to mention the potential for diluting the oil supply from fuel washing down the cylinder walls.
Unlike gasser motors, our rpms are usually fairly low (most power is done before 3200 rpm -- gassers are just getting warmed up at that speed!). That means that we do not need the same static timing as do higher rpm motors, nor does bumping past a certain point actually help produce "more" power. It gets as good as it gets, then starts getting worse. About 16.5* "seems" to be the max that a close to stock engine can hold. Conversely, the Dodge factory specs of around 10* (or less if the pump gear has slipped) means that we're not getting what we should from the engine. Finding that happy medium, where cylinder pressures are at a good peak, without getting too high, is key to best power and efficiency.
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ArizonaRedneck (04-28-2010)
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I did mine with the timing cover off, but no need to go to that length to set timing this way. Also, since doing it, I've procured the correct tools to check my results via the #1 DV with the dial indicator. I'll do so one of these days when I have everything apart and see just how close I got with the simple method.
Oh, and just in case you screw something up, you can go back to factory timing very simply by using the timing plug that us under the big cap on the side of the pump. Pull off the cap (loose a little oil that is inside the pump -- don't worry, it refills once the engine runs from engine system oil pressure) -- flip the little peg with the groove backward -- align the pump so that the foot fits exactly into the groove in the peg -- timing is set to factory specs. Articles detailing this are on-line. I think Geno's has one in their database of articles.