Timing Question

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so the mechanical advance plate is setup to put 30 degrees of mechanical timing in. You'll have to limit them (weld in some stops) especially since you have made them even longer. Currently you have 12.5 initial and 55 degrees total (initial + mechanical no vacuum advance) so that means the plates now let 42.5 degrees of mechanical advance in. You'll have to limit the plates to get a total timing of 32-36 degrees (initial and mechanical no vacuum advance), so limit the plates to 20-22 degrees . That should take care of your pinging issues. It might be easiest (if you have the money) to buy a new mopar performance distributor from summit racing.
 
67cuda360 said:
so the mechanical advance plate is setup to put 30 degrees of mechanical timing in. You'll have to limit them (weld in some stops) especially since you have made them even longer. Currently you have 12.5 initial and 55 degrees total (initial + mechanical no vacuum advance) so that means the plates now let 42.5 degrees of mechanical advance in. You'll have to limit the plates to get a total timing of 32-36 degrees (initial and mechanical no vacuum advance), so limit the plates to 20-22 degrees . That should take care of your pinging issues. It might be easiest (if you have the money) to buy a new mopar performance distributor from summit racing.
Click to expand...

If the numbers the OP posted is accurate you are right.

I still say, "start from square one.";

Get or make a piston stop and figure out where TDC is. A guy in good physical shape should be able to do this in 1/2 hour.

For the moment, disconnect and plug the vacuum and forget about it for the time being

Then set total timing at (for test) 35 if you are sure you have accurate markings, and at the end, REV the engine up quite high to be sure it's "all in." Some "stocker" distributors have REAL stiff springs, and the LONG slow advance is not in until quite "late" (high RPM)

Then get the thing to idle as slow as it will go and see where the mechanical retards to.

I'm not sure I understand why this is called a "performance" package if the advance is a long as it seems to be.

I agree, if the plate is marked 15, that is probably "distributor degrees" which would be 30 at the crank. Way too long for a performance curve.
 
55 degrees of timing on pump gas? Not with anything over 8:1

You need to pull the total timing down 10 to 15 degrees, depending on compression. With your 12.5 initial, you should only need another 25 to 30 in the distributor - not the 42.5 you appear to have.

B.
 
Ok back to square one, I will re affirm TDC on the damper and go from there....
 
good idea to go back to square one, but regardless of the damper position, it seems like you have way too much advance in the mechanical plates, no way to fix the issue without limiting the advance. JMO
 
67cuda360 said:
good idea to go back to square one, but regardless of the damper position, it seems like you have way too much advance in the mechanical plates, no way to fix the issue without limiting the advance. JMO
Click to expand...

Only other work around is set the total mechanical for what it will run, maybe change to lighter springs or even remove one spring, and see if you can "put up with" the lesser initial.

I used to do that with a stock type dist. Don't know for sure (stock breakerless) what it was out of. Back then I used to run close to 38-40 total. I just set the damn thing for 40, reved it to the nuts to make sure it was "all there" and as I remember, it ended up with about 12 initial. I just pulled of the one big spring and ran it.
 
The distributor that was in it when I ran pertronix was points distributor converted to pertronix. With that distributor the car ran fine, when I put Mopar's electronic ignition in, I found a fairly new distributor in a truck at the Junkyard. I then converted the car to Mopar with an orange box, and that is when I started chasing my tail on this issue. I used the springs from the old distributor and put them in the distributor I have in the car now and that helped a lot, it cut down on the pinging quite a bit and also when I by passed the ballast resistor it even helped more.
 
64X2 said:
I found a fairly new distributor in a truck at the Junkyard..
Click to expand...

Truck engine's are generally low compression and therefoe have a wide advance curve.
Sounds like a true pointer to your problem.

67dart273 and 67cuda360 - very good posting,advice and help for this fellow.
 
So, my thinking got me in trouble. I need to control the advance amount and rate. I think I am going to weld up the slots to control how much advance I am getting, then find the best spot for initial then mechanical. So is there a formula for the length of the slot versus how much advance I need to take away. I am not sure where to start.
 
I would assume you would be able to measure the length of the slot that you currently have and figure out how much would need to be blocked off to get the number of mechanical advance that you would like.

Based on the numbers you gave, it seems that the slots currently allow 42.5 degrees of mechanical advance. That would mean if you divide the length of the slot by the amount of degrees then you can get the distance per degree.

For example; if the slot is 10mm long then for every mm it is letting in 4.25 of mechanical advance degrees (this is degrees at the crank not distributor degrees). By calculating it this way you should be able to mark where it needs to be welded up and get pretty close to a perfect reading.

So if you are currently running 12.5 initial then you only want about 22-24 degrees of mechanical, so since we know the plates currently allow 42.5 it seems that the plates will need to be welded at just slightly over half the length of the current slots.

Maybe someone else here on fabo can shine in on this.
 
I wonder if I can get less more initial or do I go with what I have based on the fact that it starts and runs. I have messed with the timing so much I am not sure if 12.5 is enough or to much. I have to get the damper issue squared away. I need to be exact as possible I think that is where I went wrong trying to make junkyard parts work without really thinking about what I was doing. Sometimes learning is a hard process that can't be rushed and thinking that you have all the answers will bite you in *** quick. Thanks again to everyone for helping me better understand all of this.
 
LOL, that's how we learn right... I would definitely start at square one like 67dart273 suggested, make sure the dampener marks are correct and that it show 0 for 0 at TDC, use a piston stop to be absolutely sure. Buy some timing tape to degree the dampener, always great for future reference.

Then I would go by setting the initial timing by the highest vacuum reading like I mentioned in the earlier post. This is a pretty good method to find what initial timing the engine combination wants and likes most for good performance.

Based on the initial timing number calculate how much mechanical timing you would need to get the desired total timing for your engine (initial + mechanical but no vacuum advance) and then limit the mechanical plates by welding in some stops like I suggested in the last post.

67dart273 had a great suggestion on removing one of the mechanical weight's springs so only one weight would be operational for the mechanical advance, therefor only using about half of the mechanical advance timing, if I understood him correctly.

This would be very easy to do and would make a huge improvement over what you are currently running. It would be interesting to see what the total timing (initial and mechanical) is with only one mechanical weight at work...

You'll get her figured out and will be burning the rubber in no time LOL
 
67cuda360 said:
67dart273 had a great suggestion on removing one of the mechanical weight's springs so only one weight would be operational for the mechanical advance, therefor only using about half of the mechanical advance timing, if I understood him correctly.
Click to expand...

No removing one spring just speeds up the advance rate, does not change amount of degrees.

What this "seems to do" (back when we did it) is if you need a quick advance, and don't want to mess with the slots, what you do is remove one (I sometimes ran NO springs) and set the timing at TOTAL. The hope is that the advance is then quick enough that it is already into the curve even at med. RPM, even though the actual "low idle" initial might be down around 5-8, by the time the thing is idling at 1200 or so, it's already into the curve
 
Just got back from the junkyard managed to score another small block distributor out of a 78 cordoba. I want to try this distributor and see if it puts me closer to where I need to be.
 
IMG_0202-1.jpg

Found a 11 advance stop..

IMG_0208.jpg

Disassembled..
IMG_0209.jpg

IMG_0207.jpg


IMG_0206.jpg

Major Difference...

IMG_0205.jpg

Reassembled....

IMG_0203-1.jpg

installed...

http://s2.photobucket.com/albums/y19/mopar65/Running/?action=view&current=IMG_0211.mp4
Running...
 
My Initial is still at 12 and with the 11 x 2 equals 34 initial and mechanical total...

Now to mess with the springs and vacuum advance....The car runs completely different much stronger...still more there........

and no ping or knock runs straight smooth.......:burnout:
 
64X2 said:
My Initial is still at 12 and with the 11 x 2 equals 34 initial and mechanical total...

Now to mess with the springs and vacuum advance....The car runs completely different much stronger...still more there........

and no ping or knock runs straight smooth.......:burnout:
Click to expand...

Perfect, sounds like you found your problem. Now let the burnout fun begin LOL
 
!! OH !! this is great news. Sound to me like you are on the downhill side of this problem.
 
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