Combining tactics for performance

[PareosWC]

Hey greybeards!  I'm attempting to be a student of proper sequence troubleshooting, but in doing so, I've confused myself.  I like to use a good vacuum gauge, dwell meter, and tach when tweaking my 40's Dodge and Jeeps.  If you have a solid-starting and running ol' flathead, what is the step-by-step method for ensuring that air, idle, spark, mixture, and timing are as solid as possible?  Here's my example:

 

1.  Get vehicle static timed first to ensure at least she cranks up and idles.

2.  Set mixture and points gap for basic recommendation from manual.

3.  Once warm, adjust distributor clockwise/counter clockwise to ensure dwell is perfect.

4.  Adjust idle to match around 650rpm (for flathead 6)

5.  Adjust mixture screw to vacuum gauge setting between 17 or whatever is highest vacuum reading.

6.  If idle creeps up with adjustment, set idle at a lower recommended RPM, and go back to getting the highest vacuum reading.

 

Does this sound like a decent procedure?  The most important item for me is that correct fuel/air mixture.  I reckon it's because the motor is loose, it always smells a bit rich, although no smoke ever shows...

[grubby65]

1 hour ago, PareosWC said:

Hey greybeards!  I'm attempting to be a student of proper sequence troubleshooting, but in doing so, I've confused myself.  I like to use a good vacuum gauge, dwell meter, and tach when tweaking my 40's Dodge and Jeeps.  If you have a solid-starting and running ol' flathead, what is the step-by-step method for ensuring that air, idle, spark, mixture, and timing are as solid as possible?  Here's my example:

 

1.  Get vehicle static timed first to ensure at least she cranks up and idles.

2.  Set mixture and points gap for basic recommendation from manual.

3.  Once warm, adjust distributor clockwise/counter clockwise to ensure dwell is perfect.

4.  Adjust idle to match around 650rpm (for flathead 6)

5.  Adjust mixture screw to vacuum gauge setting between 17 or whatever is highest vacuum reading.

6.  If idle creeps up with adjustment, set idle at a lower recommended RPM, and go back to getting the highest vacuum reading.

 

Does this sound like a decent procedure?  The most important item for me is that correct fuel/air mixture.  I reckon it's because the motor is loose, it always smells a bit rich, although no smoke ever shows...

3)  Adjust the timing by rotating the distributor, set dwell by adjusting the point gap.  I would use a dwell meter for this purpose.

 

[kencombs]

37 minutes ago, grubby65 said:

3)  Adjust the timing by rotating the distributor, set dwell by adjusting the point gap.  I would use a dwell meter for this purpose.

 

Agree with that advice.   Also I'd reduce the idle speed to around 550 at the final setting.  Mixture and idle stop settings may need to be reset numerous times as timing and dwell get brought into the right range.  They all play together.  I always set timing last, using a vacuum gauge, not timing light.  Then road test to assure that it pulls well in high gear at low speed with no pinging and starts with no kickback

[PareosWC]

Ok- great call and great information.  Although the vehicle runs well, I felt that the idle would not want to go below 900rpm, as it was just loping like an old HD Shovelhead.

[DJ194950]

Nothing wrong with a lope on a shovelhead but not so much on a stock flathead Mopar. Something needs adjustments and/or repair.

 

Best of this is when you get it correct, it will be rewarding when a stick shift car will idle at 450 rpms!. Quiet!!   ?

The semi autos require a bit higher rpms but not too much.

 

DJ

[Sniper]

On 2/15/2021 at 4:43 PM, kencombs said:

They all play together.

 

This is key.  All the adjustments you will make interrelate, some more so that other.  Changing dwell will change timing, for example.  just keep going back and forth till it's well sorted.  Once you get this done future tuneups will be simpler as you will fine tuning mostly.