Total Timing Clarification

[AMXguy]

If I have this right, total timing is initial plus machanical advance when all in + - 2500 rpm right? or is it with the vacuum advance included as well?

 If you have say 36 degrees without the vac advance hooked up, then hook up the vac advance you'd get something like a grand total of say 50 ?  I hear guys talking 50-55 degrees total  timing, that has to be with the vacuum I assume?that seems like a lot no matter what.

[Changin Gears]

You are correct on everything except it might take 3500 for all the mech advance to come in.

50+ degrees is common with vacuum.

[71chally416]

    With the vac disconnected rev the motor as high as you need to find the max advance. If it seems you have to rev it too high you need to work with the weights and springs that are under the plate in the distributor to get it to advance quicker.

[Strawdawg]

the rpm at which advance is all in is dependent on the springs and weights in the distributor.

Vacuum advance is dependent upon the vacuum the advance cannister sees and the strength of the spring in the cannister....50-55 is not abnormal at cruise when best mileage is being sought.  Remember that as soon as your foot comes down, the vacuum goes largely away and you are back to the total mechanical advance provided by the distributor.

[Aussie Challenger]

  Depending upon application/driving needs vac advance may not be needed, it is only there for economy. At light throttle there is usually lean mixtures and they take longer to burn so more advance is needed for complete burning.
  Again depending upon motor mod's max mechanical advance up to about 36* around 2500 - 3000.   

[dodj]

  Depending upon application/driving needs vac advance may not be needed, it is only there for economy.

I didn't know that! It has no use on a car that is built for performance? 

[Aussie Challenger]

 

I didn't know that! It has no use on a car that is built for performance? 

  If the car is used solely for performance then it is not connected, some people build performance motors but use them on the street for cruising, then it is optional.   

[Changin Gears]

In fact for a race only vehicle that is not operated at low RPM you can lock out the mech adv also.  You just need seperate ignition and starter switches.

[71chally416]

The MSD Digital-6 has a built-in retard for starting in addition to the rev limiters. FYI

[Ck[FIN]]

I have 15:1 compression small block with solid 36 degree advance. It has msd 7 with no retard option at startup, it starts really well with full battery. If the battery is a little bit low then i need to crank the engine first and then flip the ignition on. Oh, and it has mopar performance mini starter.

[dodge freak 2]

I have an MSD E Curve dist, it has no springs or weights, just two switches to change the rate and amount of advance. I love it, timing seems more stable and always moves so smooth no mater how fast I wing the throttle open and shut.

I did not love the price of $400 thou but its been two years now..a good 20 months of use and no problems at all.