I am experiencing an ignition problem that I'm hoping someone can shed some light on. I have a boat with twin big block Chevy 454 V8 engines.
* One of the engines has 8 degrees BTC of initial advance (at idle) and 34 degrees BTC of total advance at 2800 rpm. This is great, the engine performs perfect.
* The other engine has 8 degrees BTC of initial advance (at idle) and 16 degrees BTC of total advance at 2800 rpm. This engine is not performing to its potential. While at full load/full throttle, it is 700 rpm down from the other engine.
Here is where my confusion begins. These distributors have no mechanical or vacuum advance mechanism, nor do they have any outside control box or computer. As seen in the pictures, there are only two connection ports, as 2 pin, and a 4 pin, only one of which is used (the 2 pin port). So my question is how do these distributors introduce more timing advance as the rpm goes up? Are the ignition modules in the distributor pre-programmed to increase the timing as rpm increases? I have included all the numbers I can find from the distributor that seems to be falling short of total advance.
- Electronic / Mallory YLE 624 AV
- Listed 339F
- SAE J1171
- Module # TRANSPO-CN
- DM15 5HD-3029
* One of the engines has 8 degrees BTC of initial advance (at idle) and 34 degrees BTC of total advance at 2800 rpm. This is great, the engine performs perfect.
* The other engine has 8 degrees BTC of initial advance (at idle) and 16 degrees BTC of total advance at 2800 rpm. This engine is not performing to its potential. While at full load/full throttle, it is 700 rpm down from the other engine.
Here is where my confusion begins. These distributors have no mechanical or vacuum advance mechanism, nor do they have any outside control box or computer. As seen in the pictures, there are only two connection ports, as 2 pin, and a 4 pin, only one of which is used (the 2 pin port). So my question is how do these distributors introduce more timing advance as the rpm goes up? Are the ignition modules in the distributor pre-programmed to increase the timing as rpm increases? I have included all the numbers I can find from the distributor that seems to be falling short of total advance.
- Electronic / Mallory YLE 624 AV
- Listed 339F
- SAE J1171
- Module # TRANSPO-CN
- DM15 5HD-3029