The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: mrclubike on March 14, 2017, 08:38:18 PM
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DO THESE MODIFICATIONS AT YOUR OWN RISK !!!!!!!!!!!!!!!!!
Was able to mount up a General Motors early style 4 pin HEI ignition module Part #D1906
Used on all US GM Cars and trucks built in the late 70's to early 80's
It appears to be working just fine with the stock bean can and a 1.5 OHM Dyna Coil
I mounted to a heat sink I bought at the local electronics store
For a harness I cut an old stock one up I had extra
Next step I will be mounting up a GM DIS coil pack
I am also Looking to modify the Bean can to be able to change out the Hall Affect sensor without taking it apart
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Here is the wiring diagram I used
Top one is with hall effect Bean can
I am not sure how long the hall effect sensor will last with the HEI module
The OEM ignition module supplies the voltage to power the Hall effect and it appears to filter that voltage some how because it runs about a volt lower than battery voltage to it
Lower would be with Points
I see no reason not to use it with points
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Here is what it looks like Mounted up
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Very cool! I'm not sure about how happy the bean-can Hall sensor will be with this type of experimenting, though. I've read all kinds of things that users blamed for the demise of their can!
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I am also a bit concerned about the hall effect also but it is only carrying 15 milliamps
So I am thinking it should be OK
But I am still going to try to fit this Sensor to a Small bracket that will insert thru a Hole cut in the side of the Bean Can
It is also a GM part used in late 80's
If I am Able to do this Sensor mod it will be a huge improvement in availability of the part and ease of a roadside repair
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This is a really cool (and relatively) inexpensive mod!
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This is a really cool (and relatively) inexpensive mod!
You got that right. A HE that can be sourced on the side of the road!!! I could be turning into a "black box" guy from a staunch "points guy"
Nice work Mrclubike
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Very neat installation.
I predict no side of the road problems.
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What coil resistance do they work with?
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The original HEI coil (the one mounted in the Dist cap)
has a primary resistance of about .5 to .6 OHMS
But the hall effect sensor triggers the Ign Mod differently than the original trigger did
But all that being said the 4 Pin HEI Ign Mod has been adapted to all kinds of ignition system so it must be very robust and dirt cheap
The above ME57 Hall Sensor is only $16.00 but they normally cost more but are available
Oreilys list them for about $70.00
But at 16.00 I was willing to try it
I am mounting a standard OEM type Hall sensor first and then when the ME57 comes in i will try to mount it on a bracket also
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Here is the coil mounted to a MSD 8871 Coil stacker and the bracket i made to mount all of it
It is tight but fits
It has Primary resistance off about 1.2 OHMS
Delco Part #D555
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Very cool! I'm not sure about how happy the bean-can Hall sensor will be with this type of experimenting, though. I've read all kinds of things that users blamed for the demise of their can!
I think you are correct It appears the OEM ignition module filters the voltage to it
So I think I will not use the HEI ign module with the my original Hall Effect sensor
But try it with my after market one just in case it goes bad
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I did find the specifications on the HEM56 hall effect sensor that is used in the bean can
The operating voltage appears to be 4.5 to 24 volts
It also says it has built in overload protection
So I think I will go ahead and continue trying to mount an after market HE and try it
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Here are the 2 different Hall effect sensors I have looked at
The middle one is the standard OEM one
The left one is the one above I got off of Ebay
The one on the right I got out of the junk yard
As you can see they are larger than the OEM one
I just don't think I want to hack up my bean can that much to get them to fit
So I am going to stick with the OEM HEM56 HES and mount it to a bracket that bolts in from the out side of the can
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Here are pictures of the Mounting bracket and the bean can cut out
I am waiting for the paint to dry be for I put it all together
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Here it is from the inside with out the rest of the guts
And here it is mounted up
I was able to run it today
The HEI IGN module quickly got extremely hot with the GM DIS coil
So am going to have to go to a higher resistance coil
When I was bench testing everything with a 3 ohm coil I did not have this problem
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Does the HEI module have any internal dwell control to limit coil heating ? Short of hooking it up to an oscilloscope, one way of checking would be to measure the primary current through the coil. Modules with dwell control often limit the current to something like 7 Amps. If there is no dwell control a coil of such low resistance will pull much more than that. I don't think I would want much more than 7 amps as the ignition even ion average current becomes a significant load on the charging system.
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Does the HEI module have any internal dwell control to limit coil heating ? Short of hooking it up to an oscilloscope, one way of checking would be to measure the primary current through the coil. Modules with dwell control often limit the current to something like 7 Amps. If there is no dwell control a coil of such low resistance will pull much more than that. I don't think I would want much more than 7 amps as the ignition even taking into account the average current becomes a significant load on the charging system.
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From what I have read I think they do but it may be inoperative when it is triggered with the hall effect or with points
They were triggered with a Inductive type sensor in the GM application and not held on like it is in this application
I did install my 1.5 ohm Dyna coil and i left the key on with it not running and it barely heated up
I will try to run it tomorrow and see what happens
I wish I did have a scope to see what is going on
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I went for a thirty mile ride today and checked the temp of the coil and IGN MOD periodicaly
Every time I checked them they were just slightly warm to the touch
So as it stands now
I have my spare Hall Effect mounted to my hand made bracket. That mounts to the can from the outside.
The GM Delco HEI Module and a Brown 1.5 ohm Dyna Coil
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Does the HEI module have any internal dwell control to limit coil heating ? Short of hooking it up to an oscilloscope,
I hopefully I will know by the end of this weekend
I have a Oscope coming and I am going to try to figure out if it does
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OK
This is with a 3ohm Dyna coil
I tested the dwell with an Oscope and I found their is no difference between the Bosch Ign Mod and the GM HEI Mod
You will notice that the dwell in both cases match the signal from the bean can precisely
Measuring out to be 60% or 108 degs
From what I have found on the net is dead on
I checked it at 1000 rpm and 4000rpm with no change
From what i can tell it is only dropping the voltage to the coil about 1 volt no matter what the rpm is
It may start dropping or compensating with a lower resistance coil but I have not checked it with a lower resistance coil yet
When i get time I will check it with a.7 ohm Dyna coil
I have a secondary voltage prob and amp prob coming
Then I will check the secondary voltage and primary amperage with a 3 ohm and .7 ohm and see what happens
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Good stuff. So the hall sensor provides a fixed dwell. It now seems unlikely that there will be speed related dwell control even with the 0.7 ohm coil but it will be interesting to see if it limits the maximum current. I think it must do. I noticed the Vce voltage drop across the output transistor as a small reduction in current compared to a points set up with the same coil. To say I'm rusty on electronics would be an understatement but I wonder if Vce will rise as the current increases with the 0.7 ohm coil. That in itself will limit the current flow at the expense of a lot of heat dissipation. I would have thought current limiting should be more sophisticated than that though.
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MrClubike,
I was told that the latest BMW OEM electronic modules have a modified circuitry able to provide dwell control and current limitation at the coil in order to accommodate the old crack-o-matic gray coils and the new improved coils.
Of course, this could well be urban myth but then why change P/N ?
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Here is a picture of the Bosch mod I am using
I do not know if it is original to the bike
It does however shut off the power to the coil when the motor is not cranking
According to Snowbum may indicate it is later but it is difficult to know :o
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MrClubike,
I was told that the latest BMW OEM electronic modules have a modified circuitry able to provide dwell control and current limitation at the coil in order to accommodate the old crack-o-matic gray coils and the new improved coils.
Of course, this could well be urban myth but then why change P/N ?
I have a feeling this is correct
I am thinking the Alpha electronic advance Mod have modified this circuitry to change the timing along with the dwell
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Good stuff. So the hall sensor provides a fixed dwell. It now seems unlikely that there will be speed related dwell control even with the 0.7 ohm coil but it will be interesting to see if it limits the maximum current. I think it must do. I noticed the Vce voltage drop across the output transistor as a small reduction in current compared to a points set up with the same coil. To say I'm rusty on electronics would be an understatement but I wonder if Vce will rise as the current increases with the 0.7 ohm coil. That in itself will limit the current flow at the expense of a lot of heat dissipation. I would have thought current limiting should be more sophisticated than that though.
I do not have the latest Bosch OEM mod to check
But I do have the Alpha Emerald Island sytem (electronic advance) that I will throw on and test
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After over 3000 miles Still running the Delco Ign mod and a 3ohm Dyna Coil
with my quick change hall effect sensor and have had no problems
It does start better but who knows if this is the reason for that or not
The Delco Reg and Diode board is also working just fine but the rotor did fail about 2 weeks ago
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I see a new "garage business" in your future!