Too much timing???

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crackedback said:
Are you picking the RPM to observe total or are you revving it up until it stops advancing?

I'd try another distributor in the car to see if it has the same "adding timing" issue.

I use drill bit shanks of appropriate sizing to set mallory style advance distributors. I noticed that the stepped keys aren't always accurate.
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That's where it stops. It used to be all in by 2500 and stay there. Now at 2500 its right where it should be but as I get to 3000 it starts to move up and stops moving at 3500. I don't have an extra distributor around so was trying to narrow it down before I went out and bought one.
 
dgibby said:
That's where it stops. It used to be all in by 2500 and stay there. Now at 2500 its right where it should be but as I get to 3000 it starts to move up and stops moving at 3500. I don't have an extra distributor around so was trying to narrow it down before I went out and bought one.
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I would look at what you have before buying something new. That particular. Advance mech is pretty simple.
 
Ok now I see;You could not give me that unit.I suspect the stop arms are either bending or IDK, somehow acting like springs.
However, there is a common sense solution to this.
Next time it's hot just rev it up to 4000 and reset the timing to 36*. Let the cold timing be what it will be.If you end up short on initial, just shorten up the slot and reset the timing, hot, at 4000. Baddabing.
 
AJ/FormS said:
Ok now I see;You could not give me that unit.I suspect the stop arms are either bending or IDK, somehow acting like springs.
However, there is a common sense solution to this.
Next time it's hot just rev it up to 4000 and reset the timing to 36*. Let the cold timing be what it will be.If you end up short on initial, just shorten up the slot and reset the timing, hot, at 4000. Baddabing.
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That's funny. That is actually one of the most reliable advance mechs I have used. And I started with GM junk and early Chrysler crap that I had to weld the stop plate on. Nothing wrong with the advance mech unit. It needs to be looked at.

BTW I buy all the Mallory stuff I can find.
 
Ok, so I get that I might be wrong. But still, no thanks.
And the common sense solution is good too. There is nothing wrong with having 25* at 2500 instead of 35*. And 35* at 3500 is also fine.

And swapping cams in an old oem dizzy is quick and easy if you drill and tap the axle-pin for a small screw and get rid of that horrible wire retainer.It certainly takes no longer than this.And when the flyweights come to the stop they are Stopped.
 
AJ/FormS said:
Ok now I see;You could not give me that unit.I suspect the stop arms are either bending or IDK, somehow acting like springs.
However, there is a common sense solution to this.
Next time it's hot just rev it up to 4000 and reset the timing to 36*. Let the cold timing be what it will be.If you end up short on initial, just shorten up the slot and reset the timing, hot, at 4000. Baddabing.
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Good idea. I'm sure I can get it to work that way. Do I need to worry or try to figure out why it is changing? or is it even too high? I live at 5000 ft elevation and run most the time between 4200 to 4800 elevation.
 
dgibby said:
Good idea. I'm sure I can get it to work that way. Do I need to worry or try to figure out why it is changing? or is it even too high? I live at 5000 ft elevation and run most the time between 4200 to 4800 elevation.
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You need to figure out why it is moving.

After that, do a little testing and see what it wants for total. As I have said, that advance mech is very simple. It may be that some corrosion has built up on the counterweights or maybe it needs a clean and lube.
 
Yes, no,and maybe.
YellowRose spent a good deal of time, giving you advice, and it's all good stuff.
My two-bits will get you down the road without blowing up the engine.
I would drive it a few hundred miles and get to know the engine. If it is 2 or 3 or4 degrees short of optimum,at WOT, you might not notice it. It kindof depends on your driving style. What I mean is, how often are you at WOT compared to just cruising around? Getting to know her, she will have a chance to tell you if she's happy under other load situations. Then maybe you can increase the initial timing, and or increase power timing or play with the rate of advance. Don't be in a hurry to slam the big numbers.
And I cannot stress this next statement enough; The vacuum advance unit can be your engines best friend, at low to moderate throttle settings, that produce manifold vacuum over about 12 to 14 inches to as high as it goes. As soon as you have the idle to 3500 timing bugged out, try to get that puppy on line.
I live at 900ft and on a huge flat plain,hundreds of miles wide. And so does every car I have ever tuned. So I can't help with altitude questions.
 
Well... got to love spring time in the Rockies... was 65 degrees last week when I started this, turned to snow and rain for the next four days, now up to 70 by Sunday..

Anyway's, third time seems to be the charm. Took the distributor out again, pulled it all a part, cleaned and lubed it and it seems to be holding the timing. Really didn't look dirty or gunked up but is working fine now. I'll check it a few more times over the weekend but I think we're good. Thanks all for the advise!
 
dgibby said:
Well... got to love spring time in the Rockies... was 65 degrees last week when I started this, turned to snow and rain for the next four days, now up to 70 by Sunday..

Anyway's, third time seems to be the charm. Took the distributor out again, pulled it all a part, cleaned and lubed it and it seems to be holding the timing. Really didn't look dirty or gunked up but is working fine now. I'll check it a few more times over the weekend but I think we're good. Thanks all for the advise!
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Cool.

That means you didn't spend a bunch of money for nothing.

Nice.
 
Unilites have had issues in the past with the optical trigger - the pickup essentially. Given it's always when it's running-temp-hot, I'm leaning towards the pickup going south.
 
moper said:
Unilites have had issues in the past with the optical trigger - the pickup essentially. Given it's always when it's running-temp-hot, I'm leaning towards the pickup going south.
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They either work, or they don't.

Never seen one change timing like that, and I've been using em since 1982 and still do.
 
moper said:
Unilites have had issues in the past with the optical trigger - the pickup essentially. Given it's always when it's running-temp-hot, I'm leaning towards the pickup going south.
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Which is the reason to look at the polarity of the pickup connection.... reversed will have the same issues as on a Mopar.

Having spent decades in electronics, I never say that an electrical item will only fail in a certain way LOL

But if it holds.... problem solved.
 
nm9stheham said:
Which is the reason to look at the polarity of the pickup connection.... reversed will have the same issues as on a Mopar.

Having spent decades in electronics, I never say that an electrical item will only fail in a certain way LOL

But if it holds.... problem solved.
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I know on some ignitions you can reverse polarity and have issues, but I do not believe the Unilite capable of this, with the exception of someone rewiring the plug in (which can be done if you kill the photo cell and need to replace it) reverse. The OE Mallory plug can only be plugged in one way.

Like you, except in opposite, I did my level best to stay AWAY from electronics because of what you are saying lol. I always ran magnetos on my race cars, as did my friends. My customers...that was a different issue so I had to deal with battery fired ignitions.

Electricity is a slippery foe. I trust it not.
 
Roger. FWIW..... It all depends on the rising versus falling edge characteristics of the output AND the surrounding circuits. Photocells will tend to always turn on very quickly and sharply. The turn-off can be lazy and unpredictable, or it can be sharp; that depends on the loading that the circuit that is being driven presents to the photocell. If it is a heavy load, then it will quickly drain the residual charge out of the middle ('intrinsic') portion of the photocell semiconductor junction and the turn-off will be quick and sharp. If lightly loaded, the turn-off will be lazy. So if you somehow reversed the leads and could trigger off of a lazy photocell turn-off edge, it would be unpredictable......just like the Mopar's Hall effect sensor. As said...FWIW.. just a possibility for the OP's timing changes with hot temps.
 
nm9stheham said:
it would be unpredictable......just like the Mopar's Hall effect sensor. As said...
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That happened to me once! I found myself broken down on the side of the hiway with a failed sensor.I accidentally got a wrong polarity sensor installed, set the idle timing, and tried to check the power-timing. The light went berzerk.Then I remembered, the wire colors were different, and my little brain connected the dots. Years ago, I had found a polarity reversing patch-cord, which not knowing what it was for, I had thrown into the toolkit. Out it came and in it went. To my amazement, the idle timing was out to lunch; but the light was functioning again. So a quick reset and we were motoring again. This happened while we were quite a ways from home, and I was not looking forward to towtruck fees. Phewff!
 
nm9stheham said:
Roger. FWIW..... It all depends on the rising versus falling edge characteristics of the output AND the surrounding circuits. Photocells will tend to always turn on very quickly and sharply. The turn-off can be lazy and unpredictable, or it can be sharp; that depends on the loading that the circuit that is being driven presents to the photocell. If it is a heavy load, then it will quickly drain the residual charge out of the middle ('intrinsic') portion of the photocell semiconductor junction and the turn-off will be quick and sharp. If lightly loaded, the turn-off will be lazy. So if you somehow reversed the leads and could trigger off of a lazy photocell turn-off edge, it would be unpredictable......just like the Mopar's Hall effect sensor. As said...FWIW.. just a possibility for the OP's timing changes with hot temps.
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I'm asking because you sound lie you understand this pretty well. Does the photocell on the Unilite actually pulse? I thought it was on as soon as it had power, and the shutter wheel controlled the power going to the coil.

Seems like you are saying the photocell actually goes on and off. Do you know which it is?
 
yellow rose said:
They either work, or they don't.

Never seen one change timing like that, and I've been using em since 1982 and still do.
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Incorrect. I've never had an issue with the few I've used either. But I'm not basing all experiences on my own here. Sounds like he found it anyway, but I stand with what I said.
 
yellow rose said:
I'm asking because you sound lie you understand this pretty well. Does the photocell on the Unilite actually pulse? I thought it was on as soon as it had power, and the shutter wheel controlled the power going to the coil.

Seems like you are saying the photocell actually goes on and off. Do you know which it is?
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There are 2 parts to what you might think of as the photocell: A photo emitter (probably a near-infrared LED) and a photocell. The emitter is on all the time when power is applied. The photocell receives light from the emitter and goes on and off, controlled by the shutter wheel action. The photocell's pulses (caused by the light interruption of the shutter wheel) controls a transistor switch that then switches the current to the coil. The photocell by itself cannot switch the coil current; the coil current is waaay to large for the photocell to handle directly. All of this is inside the distributor module in the Unilite design.

What I was describing was the turn-off characteristic of the photocell. In looking back at the installation diagram, I just realized that it would have to be wired incorrectly INSIDE the module..... which seems pretty unlikely unless it was a factory mistake. A long shot indeed LOL
 
nm9stheham said:
I just realized that it would have to be wired incorrectly INSIDE the module..... which seems pretty unlikely unless it was a factory mistake. A long shot indeed LOL
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But, within the realm of possibility, for sure.

This is only marginally-pertinent to this discussion, but, one of the (many) advantages of running a turbocharged slant six is, the redline on those motors is usually pretty low; the two I always refer to make upwards of 500 horsepower and, do it all below 5,500 rpm.

That is such a low engine-speed, most engine builders think it's a waste of time to use anything but a stock distributor. I think they may be right. My own setup uses an electronic MOPAR lean burn distributor hooked to an MSD 6-AL box, with a MSD Blaster II coil..... that's all.

So far (fifteen pounds of boost) it has given zero problems. If I tried to turn it 7,500 RPM, it might well be a different story. :eek:ops:

But, that won't happen; there's no point...
 
nm9stheham said:
There are 2 parts to what you might think of as the photocell: A photo emitter (probably a near-infrared LED) and a photocell. The emitter is on all the time when power is applied. The photocell receives light from the emitter and goes on and off, controlled by the shutter wheel action. The photocell's pulses (caused by the light interruption of the shutter wheel) controls a transistor switch that then switches the current to the coil. The photocell by itself cannot switch the coil current; the coil current is waaay to large for the photocell to handle directly. All of this is inside the distributor module in the Unilite design.

What I was describing was the turn-off characteristic of the photocell. In looking back at the installation diagram, I just realized that it would have to be wired incorrectly INSIDE the module..... which seems pretty unlikely unless it was a factory mistake. A long shot indeed LOL
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Ok, I get what you are saying now and it makes sense.

I'm sure all triggering systems have a lag or possibly some delay somewhere in the system. Maybe not COP type ignitions but I am still very leary of all things electrical.
 
Bill Dedman said:
But, within the realm of possibility, for sure.

This is only marginally-pertinent to this discussion, but, one of the (many) advantages of running a turbocharged slant six is, the redline on those motors is usually pretty low; the two I always refer to make upwards of 500 horsepower and, do it all below 5,500 rpm.

That is such a low engine-speed, most engine builders think it's a waste of time to use anything but a stock distributor. I think they may be right. My own setup uses an electronic MOPAR lean burn distributor hooked to an MSD 6-AL box, with a MSD Blaster II coil..... that's all.

So far (fifteen pounds of boost) it has given zero problems. If I tried to turn it 7,500 RPM, it might well be a different story. :eek:ops:

But, that won't happen; there's no point...
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LOL, I used to race my Opel stock points distributors to over 8000 RPM ALL the time... I mean thousands of times to 8000 RPM; the 2-3 shift jump was pretty crappy in that transmission. A 4 banger has plenty of dwell time no matter what though... so maybe that is cheating.
 
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