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Discussion Starter #1
Two things I don't have any clue about, can someone explain the how and why's of rotor phasing and also what and how a high speed retard works and why? I assume the high speed timing retard helps with the extra load placed on the engine in high gear? Bob
 

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Rotor phasing can only be achieved when running a crank trigger.


High gear retard. In high gear if you can have a retard it allows you to run more timing in the low gears for better acceleration. In high gear under heavy WOT load is when the most cylinder pressure and chance of detonation possibilities.

Al
 

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You should always rotor phase, even if you don't use a crank trigger. Drill a hole in an old cap next to the number one socket. Shine the timing light in the hole and make sure that the rotor is dead on the socket. Not just before it or after it. Thats when you see rotor tips burned on one end or the other. If you phase it you won't have that burning because the spark is not leaving that small of an area (the corner). Now, your cap must be adjustable in order to correct this or very soft hands. I have not been able to really do it without an adjustable cap, like the MSD pro cap. It has two set screws that allow you to turn the cap and not the distributor.

As for high speed retard, never has never worked on my cars. Higher timing produces power in the low power band and in the high power end if you retard the timing it supposedly allows the motor to produce more power because your not fighting the turn of the crank by firing so advanced before TDC. Tried it on several of them. I have friends with 7.50 dragsters that have the 7al3's with it built in and they all run zero chips in them so it won't retard. Only time ive really seen it work is in forced induction and they start retarding due to boost not rpms.
 

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Discussion Starter #4
This all makes sense- Thanks!!! An adjustable rotor sounds like it would be the easiest or if the pickup could be repositioned appropriately I bet that would also work. I bet some of the cheap import distributors may be way off. Good information, thanks again, Bob
 

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seems like to me

high speed retards were more popular with small cube motors turning some real RPM ,, 8000 +

seems like it might be worth checking though ,, just as a safety to make sure you don't hurt a piston
 

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As for high speed retard, never has never worked on my cars. Higher timing produces power in the low power band and in the high power end if you retard the timing it supposedly allows the motor to produce more power because your not fighting the turn of the crank by firing so advanced before TDC. Tried it on several of them. I have friends with 7.50 dragsters that have the 7al3's with it built in and they all run zero chips in them so it won't retard. Only time ive really seen it work is in forced induction and they start retarding due to boost not rpms.
Running a glide? 2 speed transmission!

Engine load when using a glide is very even.

When using multiple gears the use of more timing in those lower gears works.

Al
 

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HA! I work for Rockwell Automation/Allen Bradley, that is the Retroencabulator.

That thing gets brought out all of the time. What is amazing is if you watch how much of that the guy is able to get through without a cut!
 

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Discussion Starter #11
Thinking about rotor phasing.... I guess it would only work on a distributor with no mechanical advance or one that has been locked. Phasing the rotor when you lock the weight setup might be the easiest way. Change the timing and the rotor phaseing will need to be adjusted again. Am I right?
Or.... do you dial in your mechanical advance curve then just make sure when the advance is all in that the phase is correct??? I bet a person could use a small solenoid to make a high speed retard using the same principal that vacume advance uses to rotate the breaker plate? The switch would need to throw current to it through a window switch maybe so higher rpm isn't affected??? Interesting stuff...:yes:
 

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HA! I work for Rockwell Automation/Allen Bradley, that is the Retroencabulator.

That thing gets brought out all of the time. What is amazing is if you watch how much of that the guy is able to get through without a cut!
HA! Bad thing is I actually understand some of what he said! I work with AB PLC's all the time in my company's electrical switchgear.
 

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Discussion Starter #14
Thinking about rotor phasing.... I guess it would only work on a distributor with no mechanical advance or one that has been locked. Phasing the rotor when you lock the weight setup might be the easiest way. Change the timing and the rotor phaseing will need to be adjusted again. Am I right?
Or.... do you dial in your mechanical advance curve then just make sure when the advance is all in that the phase is correct??? I bet a person could use a small solenoid to make a high speed retard using the same principal that vacume advance uses to rotate the breaker plate? The switch would need to throw current to it through a window switch maybe so higher rpm isn't affected??? Interesting stuff...:yes:

back to the top in hopes for more info
 

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Discussion Starter #16
I found a few articles online and it sounds like those running a mechanical advance are dialing in the rotor phase at full advance just to make sure no chance of crossfiring occures at higher rpm where damage would be the worst. One article recomended to phase the rotor at the rpm where peak torque is made as this is where the most strain on the ignition happens. I've never checked the rotor phase on anything:no: but it makes me wonder if some of the distributors I tried may have been off. I will take the time to do this on the next build though. Interesting stuff....

High speed retard: I bet one couldn't guage the benifits on a dyno since there's no wind resistance?
 

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Rotor phase is in relation to rotor button position and the trigger position.



If any mechanical advance is used on the rotor or trigger in the dist, phasing becomes mute. In any dist with a mechanical or vacuum advance you can not phase the dist. And doing so changes the ignition timing.

The main purpose in phasing is when using a very high voltage ignition system like the 7AL drag box. This is why a crank trigger is recommended.
Ignition fire at high speed and voltage can cross fire, it can even stop firing by using up all the Oxygen in the cap area.

This was a big learning curve back in the early 80's when we first started using the MSD 7al.

In any dist with a mechanical or vacuum advance you can not phase the dist. Doing so changes the ignition timing.

The vacuum advance rotes the Trigger (pick up Assembly)
The mechanical advance changes the position of the rotor in relation to the trigger assembly.

If you eliminate all advance parts in the dist you can can phase the dist. You change the trigger position in relation to the rotor button position. Unless you have a very high voltage ignition system there is no benefit.

The MSD 7Al drag (I think they call it -2 now) would burn holes in the thin Moroso valve cover.
I was setting valves and had the plug wires laying on top of the engine when my son, 4 yrs old at the time flipped the ignition toggle at the same time as I bumped the engine. I hate ZAP!!! I mean the hair stood up on my head (I had a lot then) my arm and hand hurt for days. It was bad!

ZAP !!! I hate ZAP!!!!!!!!!!:eek::eek::eek:
 
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