Question about timing a 69 RR 383

[mpro69rr]

Lots of the older points style distributors have a 9.5 plate or a 19 degree limit.
I found one for mine, saves the welding and fileing .
As far as help when setting timing and total advance ect. It really helps having my better half running the throttle inside watching the tach.
My light is a dial back style , with her help and that light makes setting up a distributor pretty easy.

Yeah, I have a light like that too. I don't think my better half would be comfortable doing that since there is no seat, you have to press the pedal with your hand. lol

 

[65-440]

It wont matter--let that fall where it will--If you time the engine to 36 degrees with every thing hooked up it will start and run great--you can still change the initial timing by inserting an allen head key into the vaccum advance and dialing it up or down to give the initial timing you want--that is generally not need --dont forget to recheck the total if you change the vacc advance ---whats important is the total advance at 36 degrees to saturate the coil and so theres 9 degress of timing to light the cylinder-that takes up the 45 degrees for each cylinder--45 x 8 =360 degrees hope this helps--Hemidon

So not true... that's why we recurve distributors.....unless you get lucky and your engine just so happens to like whatever initial it has once you lock down total....not all distributors have the same mechanical advance!
To the OP, might I suggest.... first you need to find out how much mechanical advance is in your distributor... after that find out how much initial it likes/can take....lock that down.....next limit the amount of mechanical to get your all in at 36...

 

[HALIFAXHOPS]

It wont matter--let that fall where it will--If you time the engine to 36 degrees with every thing hooked up it will start and run great--you can still change the initial timing by inserting an allen head key into the vaccum advance and dialing it up or down to give the initial timing you want--that is generally not need --dont forget to recheck the total if you change the vacc advance ---whats important is the total advance at 36 degrees to saturate the coil and so theres 9 degress of timing to light the cylinder-that takes up the 45 degrees for each cylinder--45 x 8 =360 degrees hope this helps--Hemidon

Adjustable Vacuum Advance | For A Bodies Only Mopar Forum

 

[HALIFAXHOPS]

So not true... that's why we recurve distributors.....unless you get lucky and your engine just so happens to like whatever initial it has once you lock down total....not all distributors have the same mechanical advance!
To the OP, might I suggest.... first you need to find out how much mechanical advance is in your distributor... after that find out how much initial it likes/can take....lock that down.....next limit the amount of mechanical to get your all in at 36...

Totally agree. If your motor is stock the specifications for the distributor is in section 8 of the FSM, if modified you have to figure out what you need. There ae no externa adjustment to do that all are internally. Also watch the analogue dial backs alot of times they are inaccurate get a timing tape to be sure. Hope it helps.

 

[toolmanmike]

Curious why you need a friend to help set the timing? Run the throttle with your right hand and aim the light with your left.

You need someone inside to look at the tach.

 

[HALIFAXHOPS]

So not true... that's why we recurve distributors.....unless you get lucky and your engine just so happens to like whatever initial it has once you lock down total....not all distributors have the same mechanical advance!
To the OP, might I suggest.... first you need to find out how much mechanical advance is in your distributor... after that find out how much initial it likes/can take....lock that down.....next limit the amount of mechanical to get your all in at 36...

Remember also that will not be 36 at the crank it is 36 added to wherever you set initial, jut easy numbers you set at 10 BTDC add 30 you have 20 ATDC on the crank

 

[mpro69rr]

So not true... that's why we recurve distributors.....unless you get lucky and your engine just so happens to like whatever initial it has once you lock down total....not all distributors have the same mechanical advance!
To the OP, might I suggest.... first you need to find out how much mechanical advance is in your distributor... after that find out how much initial it likes/can take....lock that down.....next limit the amount of mechanical to get your all in at 36...

It looks like I have 24 mechanical advance. I'll give this a try.

 

[mpro69rr]

Remember also that will not be 36 at the crank it is 36 added to wherever you set initial, jut easy numbers you set at 10 BTDC add 30 you have 20 ATDC on the crank

That just mixed me up. LOL

 

[HALIFAXHOPS]

LOL new math. Where ever you set the initial you add the total mechanical to it. Starts as a negative number then past 0 and final result is positive if that makes sense. -10 +30 = 20

 

[HALIFAXHOPS]

Now to make it more confusing most advance numbers for the distributors in a FSM are in distributor degrees which is half the crank degrees. They use them when testing the distributors on a machine.

 

[mpro69rr]

number then past 0 and final result is positive if that makes sense. -10 +30 = 20[/QUOTE]

LOL new math. Where ever you set the initial you add the total mechanical to it. Starts as a negative number then past 0 and final result is positive if that makes sense. -10 +30 = 20

AH I see now, that makes sense! Thanks!

 

[Don Frelier]

LOL new math. Where ever you set the initial you add the total mechanical to it. Starts as a negative number then past 0 and final result is positive if that makes sense.

Sorry but that is just incorrect. It's always negative you are going further BEFORE TDC as you add advance.
For example you start at -10 initial add 26 more centrifugal as you speed up the motor and advance to -36 Before Top Dead Center.

 

[HALIFAXHOPS]

Lots of people get it to say 30 on the crank then it detonates badly when the vacuum advance kicks in. Just numbers thrown out.

 

[mpro69rr]

Sorry but that is just incorrect. It's always negative you are going further BEFORE TDC as you add advance.
For example you start at -10 initial add 26 more centrifugal as you speed up the motor and advance to -36 Before Top Dead Center.

So I have -18 initial now, that means I would add another -18 to get -36 total?

 

[Don Frelier]

So I have -18 initial now, that means I would add another -18 to get -36 total?

Correct with the vacuum advance unplugged.
Under high vacuum conditions the vacuum advance adds more advance and you can see even higher numbers like 45-50 degrees of advance that's when they can predetonate.

 

[HALIFAXHOPS]

Not disagreeing it is what is shown on the crank with a light I am refering to. Totally agree with above.

 

[mpro69rr]

Correct with the vacuum advance unplugged.
Under high vacuum conditions you can see even higher numbers like 45-50 degrees of advance that's when they can predetonate.

So what do I do when I hook up the vacuum advance? Will that be OK?

 

[HALIFAXHOPS]

Lots of variables. Really depends on how that Petronix is set up.

 

[HALIFAXHOPS]

This video is pretty good around 5 min in is what I mean.

 

[toolmanmike]

This video is pretty good around 5 min in is what I mean.

Wow, Frieburger was young on that video.