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Dwell 28 degrees


maok
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The meter measures the dwell at the coil, like it says, dwell still takes place at the coil, no different to points.

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18 minutes ago, maok said:

The meter measures the dwell at the coil, like it says, dwell still takes place at the coil, no different to points.

If you happy with that I am tickled pink...however, DWELL take place at the points.....SATURATION takes place at the coil...saturation is based on the dwell, your dwell meter coil connection just allows you to read how long the points stay closed in duty cycle....however, I do suggest you read a few white papers....while for sure the coil is turned off and on by the Petronix, it is not a fixed relationship like that of the points to a rotating breaker cam that at whatever speed the cam is turning the actual degrees of the saturation will remain constant up UNTIL your breaker cam wears or the points erode therein changing the dwell which now changes the saturation and the cycle of regular scheduled tune ups to correct these wear factors.  Most of these are electronic modules have mapped patterns and current limiting.  So many little things can cause each to read different...thickness of the molded plastic, angle or distance of the pickup within the molding...and distance from the trigger and well the trigger will have its variances based also on the manufacturing process...AND slight change can be made in your air gap will allow the magnetic influence to alter a tad and why these also have a recommended air gap.  

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What if the pertronix module is a lobe sensing unit?

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this is what I address in the manufacturing process making each a slight difference in reading if you did try to connect the dwell meter....you have the switching module and then you have the lobe and the air gap is fixed by production methods by Pertronix to be consistent (no elongated holes here) with the number of lobes on the rotor to be ballparked within their mapping of the module for that application.  This preset mapping also depends on voltage to the coil and why the recommended impedance of the coil is critical to operation and LONG life with the Pertronix.  Pertronix makes a good product, their failures are most often the results of users comingling components not compatible with the module and fail to read all the install tips from the Pertronix,  a coil is a coil for sure but impedance characteristics make each a bit different on application as will controlling the voltage with the correct ballast if you do not use the internal resistor coil.  E-coil will require yet another style module from Pertronix and likely not available for these cars...never checked this so cannot say 100%.    As with all things even with the right mix of parts, failure will/can occur now and then and if you do not have a spare module with you, you just cannot walk into a big box store and walk out with a fix.  This is my single drawback to the Pertronix system, you have to go online to source the component.  I believe these warranty claims/issues prevent big box stores from embracing stocking...again, my read of the product only.  Of course many that change to the Pertronix also will carry a spare distributor to limp home on, if not, I recommend this or similar redundancy plan be put into effect.  Often local companies that cater to the car builder will stock a handful of the more common module if you lucky to have such an outlet in your area.

 

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3 hours ago, Plymouthy Adams said:

typically you do not have dwell on an electronic ignition....only the older points setup did as this is the period of time that the coils is energized to ensure saturation and dwell is the manner of expressing the duty cycle..

 

This is factually incorrect.  As you state dwell is the time the coil is being energized, electronic ignitions do that as well as points.  One of the reasons HEI doesn't need a ballast is that it has the ability to vary the dwell as needed.  Electronic ignitions have dwell, it can be measured.  It cannot be, easily, adjusted though.  Here's a graphic from Pertronix.  Odds are you are reading the dwell at idle, bump up the RPM and it should increase.

 

PerTronix-Adaptive-Dwell-Control.jpg

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read the fine print again Sniper, mapped...now in bolt type for you.....read the very word also in the illustration you portray....the word is TYPICAL portray and also I never said you could not read it on a dwell meter...it will not be the same as points and it is ever changing with speed....you cannot vary this without altering the physical aspects of the device and thus rendering the mapping more than not to be problematic in operation.   You will never find an electronic ignition system expressed in DWELL, you can at best see it compared only.

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1 hour ago, Plymouthy Adams said:

read the fine print again Sniper, mapped...now in bolt type for you.....read the very word also in the illustration you portray....the word is TYPICAL portray and also I never said you could not read it on a dwell meter...it will not be the same as points and it is ever changing with speed....you cannot vary this without altering the physical aspects of the device and thus rendering the mapping more than not to be problematic in operation.   You will never find an electronic ignition system expressed in DWELL, you can at best see it compared only.

 

Electronic ignition dwell is adjustable, if you have a computer running your ignition like my Microsquirt.  What you said was that it doesn't exist.  It does.  All electronic ignition does is replace the points with a solid state triggering device.  As long as either is allowing the coil to saturate you have dwell.  Whether is a steady amount or it varies it is still dwell.  While I don't have knowledge of every modern programmable computer controlled ignition system, all the ones I do know about have dwell parameters you can adjust.

 

http://dtec.net.au/Ignition Coil Dwell Calibration.htm

 

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megasquirt (you always want to compare a watermelon to a simple seedless grape by mixing facts that don't correlate) and pertronix don't exist on the same plane...you still wrong but lets keep it in the parameters of the original question and pertronix module and not run willy nilly with a single line/statement from a paper without reading the entire context of the article, stick with the pertronix as being the heart of his system....understand what mapping is and I would say even with the GM statement troubleshooting their simple early mapped triggers in their very late to the market modules...only value the dwell meter has is to see if the dwell mapping changes with rpm.....only true troubleshooting effect of a dwell meter on these modules.  The modern ECU cannot be compared to the simple module that is the Pertronix....spend another 3 hours researching if you wish but you will not nail a lid on your concept only a nail in your coffin per se.  The simple mapping of these devices are approximate...and when set as such....work well as the final word is timing of your distributor syncing the pulse with the piston position.

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My simplistic definition of dwell:  The duration of a completed circuit from a coil primary to ground, expressed in degrees of rotation.  The latter is important, the time varies by RPM, the degree doesn't.  A  points system can't vary that.  An electronic system can change according to it's map as stated.  So, I would expect the dwell, expressed in degrees to change as does the time.

 

That is exactly why my project will be getting a GM controller, slant six modded distributor and ecoil.

 

TO THE OP:   Is your dwell a constant 28deg, or do you see a variance with rpm changes?   I would almost bet that the current version of the  product your using may  be different that older models as the maker 'remapped' it to fix issues or improve it.  I do know that they fixed them to keep from burning out when the ignition was left on without the engine running.

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Hi Ken, yes, its rock steady 28* 'ish. I have measured before this issue it was a rock steady 38*'ish.

 

The module is the Ignitor 1 with lobe sensing feature, so no adaptive feature like the Ignitor 2 that @Sniper posted the chart of earlier. The coils I have used are the Bosch SU12 with 3ohm internal resistance. 

 

Though its possible that the 2nd module is defective as well but in this case very unlikely seeing both are acting exactly the same. The original module has been working perfectly fine for the last 2 years but all of a sudden something has caused it to this situation.

 

Technical support has come back to say that its usually a low voltage or bad grounding problem but I cannot find any issues regarding this,  I even attached a wire from the base of the module to the negative terminal of the battery to eliminate the ground issue.

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I should also add that it doesn't vary with increase in rpm being the ignitor 1 module 

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5 hours ago, Plymouthy Adams said:

megasquirt (you always want to compare a watermelon to a simple seedless grape by mixing facts that don't correlate) and pertronix don't exist on the same plane...you still wrong but lets keep it in the parameters of the original question and pertronix module and not run willy nilly with a single line/statement from a paper without reading the entire context of the article, stick with the pertronix as being the heart of his system....understand what mapping is and I would say even with the GM statement troubleshooting their simple early mapped triggers in their very late to the market modules...only value the dwell meter has is to see if the dwell mapping changes with rpm.....only true troubleshooting effect of a dwell meter on these modules.  The modern ECU cannot be compared to the simple module that is the Pertronix....spend another 3 hours researching if you wish but you will not nail a lid on your concept only a nail in your coffin per se.  The simple mapping of these devices are approximate...and when set as such....work well as the final word is timing of your distributor syncing the pulse with the piston position.

 

Has nothing to do with the OP's question and everything to do with your incorrect information in response.

 

First you state electronic ignition doesn't have dwell and delve off into some tangent about coil saturation.  I said you were wrong and you are, in the above quote it sure looks like you crawfished on that.

 

Secondly, you state that you cannot change the dwell on an electronic ignition system.  No caveats given there, so again you are wrong as I provided examples of modern electronic ignition systems that do allow you to adjust the dwell. 

 

Had you stated that the original OEM style electronic ignitions were not user changeable you would be right, but that is not what you said.

 

As for Pertronix, I personally think it's a piece of junk and would bank on points before I ever slapped one of those into my distributor, buy the hype.

 

 

 

 

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if you only you would learn to read and keep your comments inline with the posting....this is Pertronix...the answers from me are correct to Pertronix and as stated mapped ignition systems...all my statement to dwell within the Pertronix and any mapped system are true and as Pertronix is as the original OEM units then thank you for saying I was right all along..

Edited by Plymouthy Adams
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So, bringing this back - Pertronix said ground or voltage issue.  It sounds like you have the ground taken care of.  What is the voltage at the Pertronix?  That very well could be the problem if this is the second one with the same dwell.  I have tried Pertronix on a good number of cars, and currently only have it left on one.  My opinion is that they are popular because aftermarket points and condensers are junk.  Might want to keep an eye out for a Dyna-Flyte dual point conversion…..

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You know if I needed electrical advice, I'm going to @sniper.

 

@Plymouthy Adams He been acting up awkward  the last few years. I'm not sure why. He has the best paint & body experience available.

 

While I believe @Sniper has the best information for electrical ..... I personally would not sell petronix too short as long as you follow the directions completely & use their coil & wires.

 

Tim's words on this thread is totally wrong. ..... I simply would like the whole community to give @Plymouthy Adams A big hug and move on..

We simply can not go forward terrorizing the guest.

 

 

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@nonstop I have many years experience with Pertronix with 3 different vintage cars, a '28 Chrysler 6, where there was no specific module available, so installed a pertronix unit with same polarity, voltage and cylinders, basically screwed it onto the breaker plate of the distributor, worked perfectly. A 6 voltage version on my '37 Dodge MC again worked perfectly and this '36 Airstream (12volt) until this issue.

 

With both modules acting in a similar manner, I don't think this is a module problem here. I did check the voltage at the coil (12.4) and red wire of the module, again same voltage reading, even increased the size of the wire to the module.

 

@Plymouthy Adams so what do you think is the issue here?

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After doing more testing all of Sunday I have found the issue. it wasn't the Pertronix...lol!

 

After going through every check possible on the Pertronix, including drilling the locating holes out to move the module closer in and further out,  yes it did alter the dwell figure on the meter but could not get it to 38*, varied from 22* to 34*'ish had no luck. I still don't understand why my dwell meter reads 28* when installed in its fixed position (where the condensor locates) as Pertronix intended.

 

When in the fixed position with 28* dwell I thought I would check my carb (Weber 38) settings, they were way out, running way too rich. So the problem after all of this was the carb adjustment not the Pertronix.

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7 hours ago, Dartgame said:

If someone has not already suggested it, call up pertronix and explain the issue you are seeing. They may be able to help.

 

FYI, it wasn't an issue with the Pertronix,

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