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Original Ignition Coil

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coil duetto
6K views 35 replies 11 participants last post by  Steve105 
#1 ·
Hi All,

I am slowly getting the engine bay of my 67 Duetto back to what I believe/understand to be 'as factory'. I think I am nearly there but I am not convinced with my current choice of ignition coil (Bosch 'Blue' coil) - see pic. below.

What is the general con-census as to what was the original fitment ignition coil - from the factory?

I am not after what is 'best' - I am after what was 'correct'.

What does everybody think?

Many Thanks in advance,

Gary
Factory RHD 1967 "Duetto"
 

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#2 · (Edited)
Wow, beautiful restoration.

I think you're right - not the Bosch blue, which probably didn't exist in 1967. My guess would be a Marelli branded coil, with an external, ceramic resistor. The early coil brackets had a flat surface (about 1" X 1") where the resistor mounted. Here's a photo I grabbed off ebay of the type of coil, resistor and bracket I'm describing:



Admittedly I'm not an authority on when Alfa transitioned from Marelli to Bosch coils, but I believe it happened after the Duetto era.

My only other comment would be to suggest that you zinc plate the housings of the voltage regulator and horn relay, since you have replated the other underhood hardware. When I judge a car, I look for consistency; evenly-dulled plating on all parts gives that "barn find" look, while fresh plating on everything reproduces the day-it-left-the-factory feeling. A mix of the two just doesn't look right. (And yes, I expect some hate mail for this remark from those who don't get concours).
 
#3 ·
Thank you AlfaJay - very much appreciated, trying to find the evidence is the hard part - at least I would know what I was looking for (or trying to recreate).

I have been thinking about the 'zinc plating' for a while - you have prompted me to put it on my official 'list of jobs'.
 
#6 · (Edited)
Thank you AlfaJay - very much appreciated, trying to find the evidence is the hard part - at least I would know what I was looking for (or trying to recreate).
Gary: Confirm with Duetto experts, like ossodiseppia or Wille R. before taking my word for it.

If they confirm that the Marelli coil with the external resistor is correct, put a "wanted" ad in the classified section - many BB members probably have these.
 
#5 ·
Looks wonderful.

I doubt the head nuts were chromed either, but if it were mine, I sure wouldn't be removing them:))
sometimes you can go too far.......forget Pebble Beach, Ville d'Este, Goodwood and the rest....get it to how you want it to look, and then drive it:)

that bosch blue coil does look a bit modern, I agree, so I'd just get a new vintage look black or silver coil and stick either a Marelli or Bosch coil sticker on it, depending what yours originally was.

is the dizzy original, or has it been replaced with electronic?...in which case I guess the bosch blue was necessary.

(I notice the B.S.AU seatbelt standard plate on the bulkhead, so its a UK car correct?)
 
#8 ·
My March 67 RHD 1600 has Bosch 041 dizzy and Bosch black coil (with brown top). Coil is mounted pretty much exactly where and how yours is, with same bracket.

Just out of curiosity, given some other recent discussions about Duettos...Is there a booster mount hiding under that washer bag? Doesn’t look like it...
 
#13 ·
Thank you spiderserie4. Have have been reconsidering the head nuts as well - I have the originals, so may put back (again, undecided). Good spot on the BS AEU seatbelt plate. It is indeed an original UK car - delivered straight from the factory to London in June 1967.
 
#18 · (Edited)
I have been reconsidering the cam cover bolts for a while now - I have the originals, so may put back..... Have have been reconsidering the head nuts as well - I have the originals, so may put back (again, undecided).
I'm not getting what's wrong with Gary's cam cover and head nuts. Is it that the plating is too bright?

Given how fresh the rest of his underhood looks, I wouldn't say that the cover & head hardware stand out as incorrect. My instincts would be to leave them as they are.

Back to coils: I might run a slightly incorrect coil before I would run a 50 year old coil. A little Google research shows that Porsche suppliers carry Bosch coils with brown tops. One of these could be painted black and the appropriate decals ("BOSCH germany" & "importe d'allemange") applied (does Osso make those?).

Something like:

 
#15 ·
Hi Ranz, Your black coil with brown top set up has come up my other research so well may be the answer. Have you got a picture of it you could post? Failing that could you describe the decal that is on it - if you have one. In answer to your other question I do not have a booster bracket under the washer bag - I understand that they did not come with boosters - not until later.
 
#25 ·
Thank you for for posting those pictures. I think the new one is a close match and might work for most folks. A little black paint and a sticker, good to go.

Here is the same plate BS AU.. as placed on my 1972 GTJ 1300 also London delivered, but on the left inner fender.
Steve
That plate is for UK seat belt compliance. I've seen a few other marques with that same plate on them. Gary had one made for his car. I provided the graphics and the company he found did a fantastic job. The best part was they do one offs at an affordable price. Gary's picture below.
 

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#23 · (Edited)
I have a Bosch coil that has a black body with a red top part number 0 221 500 002. I have an Alfa Parts Book and it said that you car could have used a Bosch or Marelli coil. The Marelli coil has a external ballast resistor similar to what was used on later Alfas, and the Bosch coil only has an Alfa Part number. I did not realize that Marelli coil and distributors were used on 105 series cars. I used to own a 1967 Spider and it had Bosch electrics.
 
#27 ·
Thank you for the pictures Ranz, that was exactly what I was looking for. :thumbup:

The common concensus then, seems to be that this coil (black with brown top and green/blue "Made in Germany" oval BOSCH decal is the one that's correct.

Thank you all for your input - now I know what I'm trying to replicate - I think it might be wise to go with a new coil with a brown top and make the rest of it look like the original in Ranz pictures. :smile2:
 
#33 ·
Exactly. He was an interesting guy - University of Washington professor, with a Maserati, two Alfas, and 60s Mustangs and Barracudas. He was a professor and a weekend bracket racer. Hence the hot rod ignition coil. I've always planned on replacing it with correct, but it works!
 
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