308 ignition module?

Geoff,

the part you are looking for is a HEI transistor ignition module. Superformance.co.uk offers one for £58.95 (part 30817105), but you may also use other HEI ignition module as long as it is the four terminals type.

The impedance between the terminals depends on the input stage and output transistor circuit, it does not matter if its different to the Marelli module. The difference between modules of different manufacturers is the maximum output current (which is set by your coil/resistor combination) and the capability to control dwell and saturation current, so it makes sense not to buy the cheapest module offered.

 

Hi there,
I am wondering if anyone can help me out here on this matter?

I have a gt4 and live in scotland so mine is a 1977 euro model rhd.

My car was fitted with beru replacement coils in the summer when the ignition was overhauled (still origional points set up), the problem is that my car is popping condensors (capacitors) every 150 miles or so and this is not good, so I ordered x2 new marrelli coils and x2 resistors, amplifiers, the very type you are talking about and was told they are the correct ones to fit, I have two of them, but currently, there is two resistors at each end of the beru coils and they only have two pins, one at each end, so I don't know if I have the right parts as I can't copy them over and if I do have the right parts, could anyone kindley post a wiring diagram? as I am completely lost here, thankyou very much in advance.
Stephen
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The ignition module was originally a GM-Delco part used on many GM products from the 1970's, they are cheap here in the States.

Also used by Alfa Romeo and some Fiats in the late 70's..

http://www.bilcarparts.com/car-part/acd1906-ac-delco-ignition-module

FYI - the ignition pick-ups for this system are also ex-Fiat 124 circa 1979 on, I believe Lancia Beta also used the pick-ups.

I just replaced both pickups and ACD1906's on a 308 with the late model single distributor....

Cheers

Da Flav

 

Great info Gregg, could you possibly tell me what wires go where on mine as im lost to say the least, the set up I have on the 308 is completely different as my resistors only have two wires, one at each end and not four pins and I am scared to destroying them, I never realised there was a cross ref for them, I know with parts there is but mine were quite expensive, thanks for your help
stephen

 

Voltage dropping resistor were used on virtually all breaker point cars from the 60s onward, shouldn't cost more than $20 if that and are available in single and dual resistor modules. The purpose of the resistor is to drop the running voltage of the coil to about 9v, which is the nominal coil voltage, while full 12v is applied only during starting by bypassing them. If a resistor goes bad, dropping in resistance, the additional full time coil voltage ~could~ destroy the capacitor(s) which are there to negate the inductance of the coil and make points last longer. There is nothing special about resistors for a GT4 (except for physical size) as long as the resistance is adequate to reduce the coil voltage to 9v.

 

Stephen,

you have a two distributor/points setup with two coils, correct? I'm not sure that you can get a HEI module running with points, as they require a distributort with a magnetic (VR) pickup.

A coil ballast resistor limits the maximum current going through the coil, so the coil and ignition module are not operated above their (thermal) limits. From what i remember the BK 2A coil has a primary resistance of 3 Ohm, which limits the current to a tame 4 Ampere, so you don't need an additional resistor (both in a points and HEI setup).

Did the capacitors on the coil or on the distributor fail?

Regards,
Adrian

 

Hi Adrian,
Yes, since around april this year the capacitors on the distributor have failed 4 times so far, one or the other fails every 150 miles or so, the 3rd time a capacitor failed I was 5 miles from home and attempted to drive back to my house, the car ended up catching fire and destroying my entire back box because banks 1234 was not firing and sending fresh fuel down the manifold and exploding inside my exhaust! ended up blowing my back box appart. The amplifiers with the coild I bought I have two, but what confuses me is that the current ones on the car with beru coils only have 2 pins and these new ones have 4, even if the coils are 9v, as stated above, would they not exceed that on start up and so the resistors are needed?, my car only started to eat capacitors when the coils and resistors were changed, maybe the resistors are a fail safe, trouble is, with the four pins I don't know what wire goes where as electrics are not my forte, I am confident on handling an electric job if I have the details in front of me but doing it blind id a no no for me.

on the bottom of the capacitor/amplifier/module or whatever its called from the four pins there are marks left side w g and right c b and the right screw hole says 2 but the instructions says nothing about any of this.
will maybe try a few more places on the net to see if I can find out how to wire these up but had no luck so far, maybe next year I will take the plunge to electronic lol

 

I see the point now..

That's not the correct ballast resistor for the older style coils, in my mind......

The correct ones are square and ride a band around the coil itself...I'll try to find a picture.....

Talk to Eurospares about what you have???

If the single distributor set up fires two coils, as on out North American cars I think my answer is correct....

 

Hi Stephen,

i've attached a quick chart how a typical wiring for a HEI/BK 2A coil would look like.

I'm a bit confused as to your setup, the 308GT4 owners guides and workshop manual i have are points/coil only but then again they are only up to '76.

Your capacitor is wired to ground and the points terminal on each distributor?
Has the ignition amplifier you have a square shape and two terminals on the top left side?
Could you post the part number or a photo of the currently installed modules and coils?
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Thankyou so much guys and also for the chart,
So what your saying in technical terms is that this amplifier is not suited to the origional marelli points ignition and condensors (capasitors on distributor), in other words will not work along with my set up?

I will post a photo on my current set up tomorrow, yes the current resistors at each side of my beru coils have only two terminals, one at each end and are white square bakelite material, maybe I should keep the current resistors in place and fit the new marelli coils? maybe return the amplifiers for a refund? superformance did say that the new amplifiers were the correct type for the gt4 and took their word that they were?
Heres the link where I bought them on the ignition page,under "coils" the amplifier even highlights gt4.

http://www.superformance.co.uk/a-308/ignition.htm

 

Aha, the two white ceramic elements are ballast resistors, not amplifiers. So it sounds like you have a points/coil setup as in the 308GT4 '77 model. The photos will be quite helpful to see whats installed.
You can get HEI ignition amplifiers to work with a points setup like yours, but this requires some additional parts. Let check out the current setup first.

Cheers,
Adrian

 

Hi ! Just an update here...
Haven't had a chance to get near the car until tonight, new year, wife and kids etc;-) so happy new year to all!

I have taken pics and once I have found out how to upload from my camcorder (lost camera) I will do so.

To update:
Went out and changed capacitors and coils, haven't fitted amplifiers and kept the ballast resistors in place, they are still beru ones on the car, noticed something funny though, the beru coils I removed had a sticker on the underside of them saying resistance for each one is 1,8 and the new coils say 0,9 so felt pretty confident that this was the problem, I fitted them and tried to fire the car up with no success;-( still coughing and backfiring as if a condensor is down, so stripped the distributor thinking that the points must be burned out, checked and they are as brand new, so I am assuming it could be a ballast resistor? fuse?
Before the car decided not to start, a few occasions beforehand, there was a clicking noise from the engine that sounded like a loose spark until warm then it went away, then suddenly the car was coughing and backfiring and won't start, I don't even know if these amplifiers can be used in place of the ballast resistors but will get photos on in due coarse.
thanks

 

Ok, was up until 3am this morning.
Took plate off distributor, points were perfect but cleaned them anyway, used some electrical cleaner inside distributor and lubricated shaft again and put together, checked resistors and they seem fine, everything seems ok but leads are only getting a random spark and thats with new coils and capacitors, wires seem fine and in place, fuse box looks in perfect condition, could it be the wire that runs to the ignition switch/battery? starter still turns over perfect....

 

Happy new year!

It is most likely the combination of your ballast resistors and coils, might also be a wiring issue so it would be good to see a photo or a drawing of the wiring setup. You can also mail me images/photos to [email protected].

With a 1.8 Ohm coil you would use a 1.2-1.5 Ohm resistor in line for a points setup, with a 0.9 Ohm coil you need a 2.0-2.2 Ohm resistor.

Running a 0.9 Ohm coil with the existing resistors (assuming 1.2-1.5 Ohm) should still work though, but its a bit harder on the points as they need to switch more current.

Random sparks might indicate that the resistance of your coil/resistor combination is too high, so the current flowing through the coil is not high enough to create a healthy spark.

 

Hi Adrian,
Managed to get camera working;-)
Here are some pics of the set up bellow.
Also noticed something as car still won't start, took my tining gun and connected to all ht leads...all show a pulse in all 8 but plugs soaking with fuel and engine coughing.

So took multimeter to coils with ignition on, coil b does not show a reading from the multimeter but coil a does, I touched the earth on the coil body with coil b and it then shows a reading...is this normal? I checked the wire from the bottom set of points and seems fine but the earth wire does not seem fine and the other gives a reading of 7.2 volts, also...before the engine died, for a small time before, there was a noise coming from the underside and opposite side of the engine as if there was a loose spark jumping around...then disapeared when the engine got warm...could this be a weak earth strap?

The battery has allways held a good charge so the alternator seems fine but I am baffled about coil b...that there is no earth on the black lead, also noticed the black/brown lead on that coil (rev counter?) showed a reading for a momment but volts collapsed to 0 momments later, Thanks for the info regarding the resistors.
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Just also as a note, here is the amplifiers that I had bought, and also the origional beru coils.
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Hi Stephen,

so your distributor and the two set of points seem to work but the current is too low to create a high enough secondary voltage to initiate a spark (its enough to trigger the timing gun though). My guess is that the coil/resistor combination is not correct, the resistance of either the coil or the resistor (or both) is probably too high.

Could you measure the resistance (Ohm) of one resistor and of one coil with your multimeter?
- Please remove all wires from one of the coils terminals and then measure the resistance across the two coil terminals
- Same procedure for measuring the resistor
- Please also measure the resistance between the engine block and each coil body, it should be less than one Ohm.

Depending on the current position of the distributor cam, only one set of points connects to ground so that is probably the reason you only see voltage on one coil (measured at the coils terminals).
However you should see +12V on one terminal of each coils though if you measure against ground (red MM test wire goes to coil terminal with incoming red wire from resistor, black MM testwire to coil body or engine ground).

There should be no ground on the black lead as long as the corresponding set of points is open, if you turn the engine a bit then you should be able to see ground on the black lead again.

• Your original (factory) setup is based on a single S127G distributor and two BZR201A coils, each with a resistor. A good replacement for the BZR201A coil is the Bosch Red coil (#0 221 119 030) including the Bosch resistor, you can also reuse the Marelli BZR201A resistors with the Bosch coil. If you can post the type numbers of the coils you currently have (Beru, Marelli) i can check if they are compatible with your points setup.

• Your distributor is unfortunately not compatible with the HEI amplifiers you bought, that might have been a mixup with amplifier modules for the 308 GTB which uses magnetic sensors in the distributor. My recommendation would be to try to return the HEI amplifier/coils and focus on the correct coils and resistors to get the original setup up and running again.

Regards,
Adrian

 

Just noticed that your photos show the BK 2A coil. If you have those currently installed, removing (bridging) the resistors might be a quick fix for your current installation.

 

That really looks like the ignition module from an early General Motors HEI ignition 8 pole distributor which has a magnetic pole piece as the inductive pick up....

 

Hi Adrian,
Thankyou so much for taking the time to work this out, my goodness, you guys really know your stuff!;-)))

I have went out tonight and tested more or less everything you have said to do,(well I hope I have done it right) so will give all the info I can.
Just one thing I must let you know is that I had ordered the marrelli bk2 coils and used a photo on the superformance website of the coils I ordered as mine was still sealed in the carriage box at that point and when I opened the box, I didn't say anything on here but superformance had sent me alternative bosch coils hmmm, then thought oh well...never mind.
I don't know if I mentioned that my car will not start, when I tested the strobe light on the ht leads, I held the gun and turned the ignition over to get a flash on the ht leads.
---------------------------------------------------------------
so here is what I checked tonight and what I have:
What should be marelli coils is: x2 bosch resistance on sticker 0,9
numbers on bosch is 0221119021 908 kw12v
---------------------------------------------------------------
Bosch coil voltage with ignition key turned to on position 7.2v
Bosch coil resistance @ 200ohm switch on meter: coil A=2.4ohm
coil B=2.4ohm
---------------------------------------------------------------
Beru Resistors with wires disconnected an ohm reading was Resistor A=2.4ohm
B=2.4ohm
Type:Beru wz18-2f
---------------------------------------------------------------
Took Old Beru coils and had reading in ohm coil A=1.7ohm
coil B=1.7ohm
Coil Types:Beru zs110 res 1,8
Connected old Beru coils and turned ignition switch to on and took reading:
coil A=6.2v
coil B=6.0v
---------------------------------------------------------------
Tried to start engine again but failed, plugs soaking wet with fuel ,coughs and backfires.
I could also maybe check to see if choke is stuck?
I don't know if the coils are giving the correct reading though?
Thanks
Stephen

 

Ooooops, I measured the coils resistance with the + - on the coil and not the engine block lol, will go back out and re-test, Im living and learning!

 

Thanks, this is quite helpful for the diagnosis. The resistance of your 2.4 Ohm ballast resistors is too high to create a decent spark with the Beru ZS 110 or Bosch 0 221 119 021 coils.

Here's what you can do:

• Purchase two Beru 0.9 Ohm resistors (Beru WZ 09-2, part #0110510008) to replace the existing 2.4 Ohm resistors. You can use either the Beru ZS 110 coils or the Bosch 0 221 119 021 coils with the new resistors, the Beru ZS 110 will give a stronger spark in this setup, so would recommend to use these.

• Purchase a set of NGK Iridium plugs (BPR7EIX are the correct type for your engine), the fine tip helps a lot with points based ignitions for hot and cold starting. These are around £6+Vat each.

• If you don't want to go for a new set of plugs yet, remove the existing plugs, clean them and let them dry before reinstalling and trying to start with the new resistor setup.

This should fix your current ignition issues. If you should ever run into a problem with your distributor condensers on the road, just remove them to get home (and post here so we can check what the reason was).

Good luck,
Adrian

 

Brilliant Adrian thanks,
Will set about this set up and fingers crossed, this must be whats wrong all along and probably fouled the plugs now to an extent that they are just too weak to spark?
I have got new plugs but haven't fitted them yet, they are not iridium ones but the platinum version with a fine tip, my origional ones have a thick tip.

Is there any other places to buy resistors? I tried and found only this place, used the part number you gave me and the same type that I currently have came up here http://seekpart24.com/search?c=100757&q=0110510008 it says the resistance is 0,9 but in the photo it is 1,8 and the same type for what I have, I will try to find a few more places on this, thanks again I owe you many beers!

 

The Platinum fine tip plugs are as good as the Iridium ones, good choice!
You can ignore the photo on seekparts, they often uses the same image for a series of products. The link you supplied points to the correct part.