Timing curve mystery

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mbaird

mbaird

mbaird
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So I was trying to recurve my distributor to slow down the advance before 2000 rpms and I kept getting faster advance than I wanted and more advance than I set it up for .
After the 5th try I decided to lock out the distributor and see id it advanced .
Yep... I set it at 20* intial and it climbed to 27* by 2000 .
My ignition is a Daytona Sensors CD-1 with a programmable curve but I have it locked to a static point. The distributors are mopar stock electronics . I have tried 3 distributors and get the same result . Although 1 seems to have a more stable reading at idle ... My timing light is an OTC dial back. It might be the issue so I will try one of my old static lights and verify .
 
mbaird said:
So I was trying to recurve my distributor to slow down the advance before 2000 rpms and I kept getting faster advance than I wanted and more advance than I set it up for .
After the 5th try I decided to lock out the distributor and see id it advanced .
Yep... I set it at 20* intial and it climbed to 27* by 2000 .
My ignition is a Daytona Sensors CD-1 with a programmable curve but I have it locked to a static point. The distributors are mopar stock electronics . I have tried 3 distributors and get the same result . Although 1 seems to have a more stable reading at idle ... My timing light is an OTC dial back. It might be the issue so I will try one of my old static lights and verify .
Click to expand...


If you can change the curve with the box, locking out the distributor will still let the box set the curve won’t it?

I’ve never used that ignition so I’m just guessing using the info you’ve posted.

Just because it’s interesting, I’ll going to look at that box and see what the programmable curve looks like.

Is this for the engine you had on the dyno awhile back?
 
Ok, I’m making the assumption you have the multipurpose race box and not the sportsman box. Let’s see how wrong I can be!
 
I would "rig" a way to test the problem by elimination. Best way is distributor machine that can operate off breakerless distributors, but there are other "ways."
1...Spose it could be a problem in the cam/ distributor drive
2...If you can, rig something like an electric drill to drive the distributor(s) for testing. Remember that the distributor rotates at 1/2 speed, so if you are testing it up through say, 2K-2500 engine RPM, you only need half that to drive the dist.
3...Maybe consider buying a 4 pin GM module and wiring it up with a used coil and plug so you can trigger your light. You will need a rigged degree wheel, even if home made, to document results
4...Substituting a non "dial up" timing light is a good idea
 
Rat Bastid said:
If you can change the curve with the box, locking out the distributor will still let the box set the curve won’t it?

I’ve never used that ignition so I’m just guessing using the info you’ve posted.

Just because it’s interesting, I’ll going to look at that box and see what the programmable curve looks like.

Is this for the engine you had on the dyno awhile back?
Click to expand...

Yes I can program in curve but its a bit akward with this box and I am not the most computer savy individual. Daytona Sensors is run by an ex-Crane engineer. Big in the boat world.

Yes same engine. After installing it I didnt feel the off idle power was near what it should be . Timing was hitting 25* by 1500 and 32 by 2100 which I fealt was too fast . I am trying for 16* intial at 850 rpms , around 20* @ 1500 , 25* @ 2500 and 32* @ 3000..... a more linear advanvce .

It could be that my timing light is not compatable with Multi Spark ...
 
67Dart273 said:
I would "rig" a way to test the problem by elimination. Best way is distributor machine that can operate off breakerless distributors, but there are other "ways."
1...Spose it could be a problem in the cam/ distributor drive
2...If you can, rig something like an electric drill to drive the distributor(s) for testing. Remember that the distributor rotates at 1/2 speed, so if you are testing it up through say, 2K-2500 engine RPM, you only need half that to drive the dist.
3...Maybe consider buying a 4 pin GM module and wiring it up with a used coil and plug so you can trigger your light. You will need a rigged degree wheel, even if home made, to document results
4...Substituting a non "dial up" timing light is a good idea
Click to expand...

If it was cam to gear related would it make a 7* difference ? I would think maybe a degree or 2 at most on all new parts.

I am searching for my old static light.
I have another OTC dial back but it will barely operate on this ignition . Random sparking....
 
mbaird said:
Yes I can program in curve but its a bit akward with this box and I am not the most computer savy individual. Daytona Sensors is run by an ex-Crane engineer. Big in the boat world.

Yes same engine. After installing it I didnt feel the off idle power was near what it should be . Timing was hitting 25* by 1500 and 32 by 2100 which I fealt was too fast . I am trying for 16* intial at 850 rpms , around 20* @ 1500 , 25* @ 2500 and 32* @ 3000..... a more linear advanvce .

It could be that my timing light is not compatable with Multi Spark ...
Click to expand...


I’m reading through the instructions right now. Is there a way to stop the box from using its advance curve? I haven’t gotten that far yet.
 
mbaird said:
Yes ... and I did that.
Click to expand...


Ahhh...so you told the box to not use the built in advance curve and it’s still advancing.

To me, that means either you didn’t actually get it turned off or the box has an issue that is still making the timing advance.

IDK but if I were you I’d seriously think about leaving the distributor locked out and I’d use that box to make the timing curve I wanted digitally. The instructions sound pretty simple too.

I’m not sure yet if you can do a 3D curve without boost or nitrous but if you can you could hook up and map sensor and build a really nice curve.

Back to reading up...
 
Rat Bastid said:
Ahhh...so you told the box to not use the built in advance curve and it’s still advancing.

To me, that means either you didn’t actually get it turned off or the box has an issue that is still making the timing advance.

IDK but if I were you I’d seriously think about leaving the distributor locked out and I’d use that box to make the timing curve I wanted digitally. The instructions sound pretty simple too.

I’m not sure yet if you can do a 3D curve without boost or nitrous but if you can you could hook up and map sensor and build a really nice curve.

Back to reading up...
Click to expand...


I do plan on creating a custom curve but was too lazy to jack with it right now. Guess this will motivate me ..lol
I have looked into a 3d curve using a MAP sensor vs Vacuum but cant say I understand all the ins and outs yet .
 
Do you have an oscilloscope? If you can rig it so you can see the delay (if any) between distributor signal and spark event, and then as you say, get your "old" light.....................
 
No to the ocsiliscope...
and timing chain is a new billet Aussie one .
I took the initiative to download the setup software for mapping the curve via the ignition box .
 
Here is my preliminary curve... looking for good street manners.
7F932779-1396-4B3B-ADA1-C4E2DB3BF681.jpeg
60702522-EFC6-4275-ABD8-8EBD50A04C93.jpeg
 
Pretty cool that it has a built in Data Logger . If I can figure it out ...lol
 
I would move the bottom of the curve up. It looks like you only have 15 degrees at 1000. That seems low to me.
 
For what it's worth, my W2 408 is at 22 initial, 32 all in by 2800. Mine seems to like a fair amount of initial. As soon as I get my E curve installed, I'm going to try locked out at 32 with a 10 degree start retard.
 
Rat Bastid said:
I would move the bottom of the curve up. It looks like you only have 15 degrees at 1000. That seems low to me.
Click to expand...

I have my idle set at 850 rpms so I am barely off idle at 1000 rpms . But I may try moving the baseline to 18*. I just dont want to screw up the idle transfer slot position or have it idling at 1000 rpm . I will be hooking my vacuum advance to a ported source ( only source) so that will kick my initial timing up 6 or 7 degrees as well as any low speed crawling I may be doing .
At least thats my theory....
 
cpearce said:
For what it's worth, my W2 408 is at 22 initial, 32 all in by 2800. Mine seems to like a fair amount of initial. As soon as I get my E curve installed, I'm going to try locked out at 32 with a 10 degree start retard.
Click to expand...

Wont that mess with your idle slots and transition ? Your idle will be so high that you wil need to competely back out the idle screws.
 
mbaird said:
I have my idle set at 850 rpms so I am barely off idle at 1000 rpms . But I may try moving the baseline to 18*. I just dont want to screw up the idle transfer slot position or have it idling at 1000 rpm . I will be hooking my vacuum advance to a ported source ( only source) so that will kick my initial timing up 6 or 7 degrees as well as any low speed crawling I may be doing .
At least thats my theory....
Click to expand...


That’s what the 3D timing map is for. You can lock out the distributor and just use the ignition box to control all your timing, including adding or removing advance based on throttle position and MAP.

The way I read the instructions is you either have to make the box not do anything to the timing or lock the distributor out and let the box run the timing.

I need to read a bit closer but it seems you have the distributor and the box at odds with each other.
 
Rat Bastid said:
That’s what the 3D timing map is for. You can lock out the distributor and just use the ignition box to control all your timing, including adding or removing advance based on throttle position and MAP.

The way I read the instructions is you either have to make the box not do anything to the timing or lock the distributor out and let the box run the timing.

I need to read a bit closer but it seems you have the distributor and the box at odds with each other.
Click to expand...

Yes that is correct. I had the box set at zero and curved a dizzy for temporary use. Now I have the software setup on my laptop and will download the settings to the box.
I also have 3 rev limiters . 1 for max rpm , 1 for burnout that is connected to my linelock and 1 for launch which is connected to a clutch switch.

You can also program shift lights for gear changes .
 
cpearce said:
For what it's worth, my W2 408 is at 22 initial, 32 all in by 2800. Mine seems to like a fair amount of initial. As soon as I get my E curve installed, I'm going to try locked out at 32 with a 10 degree start retard.
Click to expand...


What is your idle set at ?
 
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