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Discussion Starter #1

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Has anyone tried this complete distributor. I am not talking about adding petronix electronic ignition into your existing distributor.
Interesting that you mention this. I've been looking at these distributors, too. A new, breakerless, adjustable advance, distributor for under $200 is a great deal.

Here's what I found out. While the distributor may physically fit a 105 Alfa, the advance curves for 1300 to 2000cc cars are quite different and I haven't beed able to find out what the distibutor's range of adjustable advance curve is. We need to know what the advance in the distributor is as opposed to the advance at the crank. I asked Pertronix about this and didn't get a reply. This may be the the VW distributor modified slightly to fit Alfas, in which case the advance will be wrong. The distributor comes with the standard Pertronix 1 trigger unit. These are vulnerable to voltage surges and are finicky about coil resistance. A much better solution is the Pertronix II ignitor which is much more robust, resists voltage surges, and handles low resistance coils. It might be better to install the Ignitor II in your original Bosch distributor. I plan to put an ignitor II in my 1.3 Super.
 

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Discussion Starter #3
Interesting that you mention this. I've been looking at these distributors, too. A new, breakerless, adjustable advance, distributor for under $200 is a great deal.

Hi Jim,

The ebay seller has sold 8 of them so far, it would be good to contact one of those buyers to see what they experienced because they are Alfa owners.

One buyer has bought 4 of them.

It is specific for Alfa, but again who knows what kind of true information the seller is given.

Giorgio
 

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Info from Pertronix

I must have emailed on a good day, because I did get the reply below. With only 12 degrees of total distributor advance at 3050 rpm, looks like this unit is not really suitable for many of our applications.
Bob in Nashville

From Pertronix:
I have attached the curve we offer for these distributors. I'm sorry but we only offer the one "generic" curve on these distributors.

If you have any further questions feel free to contact me.
Marvin Grebow Jr.
PerTronix Inc.
Technical Department
909-273-6006
[email protected]
 

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Discussion Starter #5
What is the standard curve on the Alfa, for example 2.0L engine?
 

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What is the standard curve on the Alfa, for example 2.0L engine?
Well, you need roughly another 50% of advance - a max closer to 36 at the crankshaft, not 24. 24 degrees of total advance is about right for an air-cooled Volkswagen, so I'll bet that 180out's suspicion in post #2 is correct.
 

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24 degrees is plenty for a tuned 2L engine - just take a look at the Jim K curve. The problem with this one is that the advance starts at 600 rpm. So the advance is pretty steep through the idle rpm and that means you will have a hard time getting it to idle, especially with Webers. It will creep up to an idle rpm that is higher than you want. It would be a decent curve if it started 800 rpm later.
 

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24 degrees is plenty for a tuned 2L engine - just take a look at the Jim K curve. The problem with this one is that the advance starts at 600 rpm. So the advance is pretty steep through the idle rpm and that means you will have a hard time getting it to idle, especially with Webers. It will creep up to an idle rpm that is higher than you want. It would be a decent curve if it started 800 rpm later.
You're right Ed. I was thinking of total advance (static + distributor advance). But the 24 degrees is just how much the distributor moves. If a distributor is set at 10 degrees of static advance, another 24 would take it to 34, which is in the range of what an Alfa needs. I still think 36 - 38 would be better, but why quibble.

The problem with the Pertronix is that between 940 and max rpm, the thing only moves 16 degrees. So if your Alfa engine idles at 900, and you set the idle advance at 10, then the maximum total advance would only be 26 degrees - way too low.

It seems weird that the Pertronix distributor begins advancing as low as 600 rpm.
 

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I plotted it against other well known curves. You have to set the static at 12 degrees to get 36 degrees at maximum advance. That results in a pretty aggressive curve - a bit more aggressive than the shankle curve. Some engines may be borderline pinging on premium gas with this distributor. So probable idle issues and a fair chance of pinging with this one. There are better options, IMO.
 

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Discussion Starter #10
Did anyone got any more info on this from Pertronix, looks like they are selling lots of them for Alfa application. Found one for $159 free shipping.
 

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To be blunt, that's a sub-optimal advance curve for an Alfa. In my 123Ignition distributor I'm using the one Tom Sahines recommends as a good starting point, and it works really well in my stock 1750:

RPM LIMIT 6500 (or less if you are concerned about over revving your motor)
point 1 500 rpm 6 degrees
point 2 1000 - 6
point 3 2000 - 20
point 4 4500 - 38
point 5 8000 - 38

The curve on that Pertronix is probably a generic VW curve and isn't really appropriate for a hemi engine.
 

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Realistically IMHO, you're probably better off buying a second hand Bosch JF4 Alfa distributor, having it rebuilt (replace bushings), and then having it recurved to the fit the curve you want for your car. Then, fit a Pertronix II Ignitor and you're set.

Alternatively, you could by the Pertronix distributor and have it recurved (if it's possible) to give you an Alfa specific curve. As I recall, the Pertronix distributor combination comes with the Pertronix I ignition which is vulnerable to voltage surges, etc. The Pertrnoix II is much better.
 

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Thanks for this discussion. So, to be clear, do folks in the know feel this distributor is inappropriate for a stock 2L ('73) with an unmodified spica running on 91 octane?
Chris
 

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Seems odd to me that Pertronix can't/won't provide a real Alfa curve. I love my 123 but at half the price it sure is an attractive option for a stock motor. Anybody know how the advance works with this dizzy?

As far as rebuilding a Bosch dizzy, I'm thinking that by the time you buy a decent unit ($100), have it rebuilt and recurved ($100), add a cap and rotor ($50) and buy the ignitor II ($150) you are within a few bucks of a 123 - I'd rather have the 123...
 

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It is most likely an air cooled VW distributor with a solid state switch. Why would anyone expect it to work well on an Alfa?
 

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It is most likely an air cooled VW distributor with a solid state switch. Why would anyone expect it to work well on an Alfa?
I suppose I wouldn't except that it is sold as a replacement for Alfa motors...

pertonix.JPG

Regarding Ignitor I verses II, I have used I for years without an issue. I've never used a II but a quick google finds people complaining about the II - however those were ten year old posts so perhaps that's been dealt with.
 

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Discussion Starter #18
One thing I don't understand that it is specified for Alfa and people are buying it for other cars??
 

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See attached graph. Bosch ..009 is an air cooled VW curve.
 

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As far as rebuilding a Bosch dizzy, I'm thinking that by the time you buy a decent unit . . .
True, but as Gordon Raymond has pointed out, the JF4 is one of the best distributors ever made. It's internals are of superior quality so rebuilding one actually makes sense, especially if original appearance is important. A lot of people have these sitting on shelves. I haven't looked closely at a 123's internals but the only other modern distributor that I know of (I'm sure there are others) that would work in an Alfa is an MSD which is a very well built distributor.
 
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