First want to thank you guys for the explanations on venturi vac and manifold vac.  VERY VERY helpful. After my MSD cooked I installed my old dist. ( 57). Has pertonix kit.  Need to change advance. To update you I have put in the 2500 stall convertor, sure help, along with adding a couple thousands on the valve adjust. Now idles.  Timed to 14 int. put on vac line jumps to 55 deg.  Have an adjustable vac can. Think I need to bring that down some??  Much more power, but afraid of the 55deg.  Does not ping.  Hope you all can understand what I trying to say, little merrgie.  Need advice on advance springs and whatever you guys think will help..

Thanks in advance.     God Bless

Eddie

Lake Forest, Ca. 92630

Hi; A little info please. After you add vacume at idle what is the advance? If it does not ping then it does not have too much advance. Even 55 degrees will be OK provided it is not pinging. Other opinions please. Pete

Eddie -

As it sits - what is the maximum mechanical advance with the vacuum line disconnected and plugged?

At what crank speed does it stop advancing?

No load vacuum advance can be really large without too much worry - but I'd think 45° maximum might be more the norm. Makes me think the mechanical limits now in the distributor are a bit high for 14° initial. The internal advance limit may need to be "stopped" to control the upper end of the mechanical curve.

 
 Steve Metzger       Tucson, Arizona

Good Mornin'   Thanks Pete and Steve!!   Will check total advance this morning(after everyone wakes up-- littlle noisey). Did notice on lite throttle seems to have slight flutter-miss, could this be too much advance, also do you guys remember which to turn the hex screw to adjust the vac can??  Lookin forward  to hearing from you!! Many thanks   God Bless 

Eddie

Lake Forest, Ca. 92630

Eddie - The set screw inside the vac can is turning in a regular RH thread "nut". With the screw fixed to the diaphragm and the nut "free" to travel in the hex housing - turning the screw counter-clockwise compresses the spring - and limits diaphragm travel. Turning the screw clockwise backs it away toward the nipple freeing the spring and increasing travel. The "new" one I just put on my outfit is a "Standard" part and it takes a 7/32 hex wrench.

The instruction sheet suggests that you gently turn the screw (clockwise) until the nut has "stopped" at the full out position (it gets snug) - then count turns counter clockwise as you compress the spring. There isn't any calibration chart - I've just been driving it - and turning it a half turn and driving it.....and so on to creep up on the maximum the thing will tolerate. 

If its old and crusty inside - squirt some WD40 down the nipple port and try to free up the screw. 

 
 Steve Metzger       Tucson, Arizona

Hey Guys;;    Adjusted vac can, now 45deg.  Looks like total is about 40-42,  still no ping!!   Got a cruise tomorow so will see how it goes!!!   Next week will pull dist. plate and try to limit advance, don't quite know how to do that but somewhere someone was telling me about brazing the slots.  Will try to find the article on the net.   Again  MANY THANKS---   that's what's sooo  nice about this site-  everyone is willing to help and share!!!    God Bless

Eddie

Lake Forest, Ca. 92630

Eddie,  An hour or two at your local junkyard and you can net a couple different advance plates.  They all have two slots which are numbered.  For example, one slot may be numbered 18 and the other 13.  These numbers correspond to distributor degrees.  Double it for crank degrees.  I'll bet yours is in an 18 slot and flipping it around will probably get a more favorable maximum advance.  This is muche easier than welding or brazing.


Lawrenceville, GA

WOW-- Charlie,,    Where do you guys get all of this info..  Amazing  and really fantastic for all of us.   MANY THANKS   and God Bless   

Eddie

Lake Forest, Ca. 92630

This photo shows the flyweight section of the later version Y distributor - that shares its mechanism with vehicles up into the 80's. As Charlie says - you get two chances (slots are 180° apart) that one of the limits is more like what you want. Before you strip the thing apart - get some lighter advance springs - like the Mr Gasket #925D - so you can speed up the rate of advance if you need to.

The photo shows it with the springs removed - the upper slot of this one (about the 1 o'clock position) is stamped 18L - meaning its going to provide 36° crank degrees of advance at full travel. To use this much travel - the factory springs were pretty stiff - you had to put in 3° initial per the Ford timing specs and wind your motor to 4500+ revs to finally get the full advance. The other side of this plate as Charlie said - shows a 13L - which is just about exactly what you want.

This Ford distributor service chart shows a factory curve that doesn't get up to max until nearly 3000 distributor revs - which is 6000 engine revs. The factory spark curve was very slow in coming in - for performance you would rather limit the travel to 13° (26° at the crank) ...but get it all in by 3000 engine revs. So on the chart above you'd see it reach maximum (13°) at 1500. This will take a lighter set of springs in the distributor so the flyweights swing out quicker.

 
 Steve Metzger       Tucson, Arizona

On way out the door for club cruise,  will get back to this Monday.  Thanks for the pictures  and all the advise!!!!!  God Bless

Eddie

Lake Forest, Ca. 92630