Timing Retarding @ high RPM

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RustyRatRod said:
I've seen timing retard on the old Mopar orange boxes. Was always told that's how they were designed. I've used the chrome box. No retard. I'm not gettin in this fray, just saying what I've tried and seen. I've also heard and read here on this forum that the old Standard LX101 box does not retard timing. I've never verified that myself. I cannot remember......it was either @moper or @oldkimmer who said that about the LX101 I think. Maybe they'll chime in.

Also, I cannot speak about the MSD stuff, as I have never used it. I know people who do and have never once heard them say the box retards at high RPM.
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Again, sometimes you can only see it on a distributor machine or with a scope, but it's there.

I guess I should call Don and ask him how he got around the slew rates, but I know he's fairly busy. Maybe he'll see this and respond.
 
RustyRatRod said:
You talkin about this guy?

Baldwin Performance Carburetor
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Yup. He has a Facebook page that has a ton of video on it. Several of them show the distributor backing up...the exact same ignition MSD said won't do it. MSD has never lied. Never. And I do full on ****. Only with multiple women because no one woman can handle me. All with the wife's approval.
















For the dullards amongst us that is sarcasm.
 
The dual sync uses Hall vane sensor on tab wheel. I worked for the company that developed technology more than 3 decades ago. Used on Omni.

Running numbers. Hall sensors are frequency limited. 5-10 kHz, used to be near the upper end. That is well above the 333 Hz that V8 distributor would put out at 5000 RPM. However delay is present. A calculation of delay at 5000 RPM is about 3 degrees. Close to 4 degrees measured with light.
 
I really do not know about any other ignition system I gave up on mopar ignitions a long time ago. I had a crane box and that didn't last but one week and it burned out. I have been using MSD 6AL's and blaster II coils for a long time I never would have any other ignition.

I went with the new digital 6 unit because of the retard for start up. I like the dial delay settings built right in and it works great.

At one time I would make mecanical advance distributors with start up built in. You cannot find the lean burn single reluctor distributors any more.

So I like MSD and the stock distributor was not that great for the RPM's we're turning. I would like to get a crank trigger for the Big Block.
 
yellow rose said:
If I get a chance Sunday I'm going to call Tuner. I'll ask him again about being able to account for slew rate in electronics. I suppose it's possible.

The last time we talked about it (when I bought my distributor machine) we covered several areas and IIRC one was not being able to electronically cover for slew rate. At least not with common CDI type boxes.

In fact, one of his classic stories is about changing over from points to a CDI box and using 3 different timing lights...and the circus act that followed. Classic Tuner story.

I told him to write a book, but he won't. I told him I'll proof it for free. And buy the first 5 copies.
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The way I'm understanding this is if a box, in this case a CD box, simply works from the distributor signal (pulse) there will be noticible timing loss in the higher rpms. (compared to what the distributor is actually doing).
I think what @KitCarlson is telling us is that if a box compares two signals, one from the distributor and the other from the coil, then the box can be hard programmed to address the delay.

I don't know if Holley's CDI can do that, but I am puzzled that it seems to be a stepwise drop. At least that is how I understand the original post.
340Duster247 said:
Now I've been trying to figure out a misfire/stumble that happens above 5800 rpm. I Thought would double check my timing at higher RPMs. I perform a static timing check @ 34degrees ( For you non EFI guys this is like locking out your timing) and it stays pretty steady with minor fluctuations but once I get to 4-4500rpm in drops to 30 degrees. No matter how much I adjust and add to my inductive delay I still get that drop and timing retards. If I add too much inductive delay , the RPM below 4000 it will advance the timing as it should but once it gets above it retards back to 30 and fluctuates.
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Mattax said:
He is. He's posted occassionally on a moparts and RFS.
Copying FB links is PIA. (in other words can't figure out what I did before. :rolleyes: )
But one of the videos is in this post - hopefully its visible.
Mopar orange box retards timing?

He's the only guy I'm aware of that has video of it on a machine, but I've seen it live on engine and machine.
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There's at least one video there of an MSD box. I can find it, but damn if I know how to link it here.
 
Mattax said:
The way I'm understanding this is if a box, in this case a CD box, simply works from the distributor signal (pulse) there will be noticible timing loss in the higher rpms. (compared to what the distributor is actually doing).
I think what @KitCarlson is telling us is that if a box compares two signals, one from the distributor and the other from the coil, then the box can be hard programmed to address the delay.

I don't know if Holley's CDI can do that, but I am puzzled that it seems to be a stepwise drop. At least that is how I understand the original post.
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I'm not nearly as well versed in electronics as I should be. So maybe there is a way to correct the retard in these boxes by electrical means.

Some day, I'll have my distributor machine up and running and I can do some testing. Someday.
 
No, what I am saying is the Hall sensor in the distributor lags, at higher RPM, the same lag is more degrees. At 500 RPM it would be 0.3 deg, hard to measure.

If I wanted test a distributor, I would make a fast trigger circuit for timing light, or strobe light and test it right at distributor. Spin it with drill press, I have done that.

About logic analyser, I use Saleae, their software to is nice for interpreting data.
Logic Analyzers from Saleae - #1 with Professional Engineers
 
We are really getting into the depth of timing lag here. Should I unplug the henway? Or leave the henway plugged in?
 
In your case keep the henway, but feed it more fish. :)

Timing advance, is timing retard, from a more advanced reference point. What point you going to use? You could add another pickup sensor x degrees ahead... Remember lean burn, how did those workout? The problem is RPM changes time between ignition pulses, higher RPM shorter time. The guestimate, good only at steady RPM. It would be like using a snub nose at 100 yards, on a moring target. Mannix was good at that.

The obvious solution, advance distributor a few deg, retard the low end, my systems can do that. Basically, give the engine what it wants. Only you will know of the offset.
 
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