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In that they have electronic sensors instead of points and condenser, yes. Magnaspark II is centrifugal advance, while Pertronix offers a vacuum+centrifugal option. My Speedster was equipped with a Magnaspark II when I bought it, and had terrible off-idle stumble and low end performance. When I replaced it with a Pertonix SVDA distributor, the difference was night and day. Distributor advance needs to react to both throttle position and engine RPM to be effective, IMO. 

Thank you Eric, what I wanted to know and was not clear about is the method of assigning the spark I believe that the Pertronix is a Hall effect device basically a revolving magnet. I wanted to know if the Magnaspark was the same. I have the Magnaspark but I’ve seen a test where the Pertronix is all over the place at higher rpm. The test was on the 123ignition website, obviously it’s dizzy was very stable.

Hall effect triggers are perfectly accurate. The problem with Pertronix is the distributor itself is usually inaccurate COMBINED with shoddy electronics that only make it worse.

A crank trigger is the most accurate: there is no slop there. Add up the backlash of every gear/interface though: to first the camshaft, then to the distributor drive, then between the drive and the distributor, then to the distributor itself. The slop all adds up.

The original Pertronix I had in the 80s in my Scirocco was absolutely flawless. Such as it is with the ever decreasing quality of merchandise today, and we all know where it's made.

There's nothing natively wrong with Hall effect sensors, or distributors. They're limited, for sure (you're pretty much stuck with the advance curve built into the distributor), but a well made distributor and pickup can be dead-nuts reliable

... which is not the case with 99% of the VW aftermarket. Most VW distributors are to OEM-grade stuff as a set of EMPI IDF copies are to actual Italian IDFs.

This is actually a pretty good comparison - because yes, while EFI is way more adjustable and better by every possible metric than any carb, well set-up carburetors are near-miracles of the mechanical age and do very, very well. The copies can be made to work OK-ish in the right hands by the right people sometimes, but they are pretty much garbage out of the box.

So, while EFI is just clearly better - a set of nicely made European (or domestic, in the case of the old V8) carbs can be made to be very, very nice. A set of east Asian copies, not so much.

That's the issue with distributors and especially with available Hall effect pick-ups. Yes, there's slop in the drive, but this was almost imperceptible to tuners back in the day, and won't make a difference to 99% of hobbiests. What is awful AND easily perceptible is how shabby, unpredictable, and altogether crappy the advance mechanisms of the Pertronix distributors are, and how ridiculously irregular the Pertonix Hall-effect pickups have become. A better distributor with a better made pickup would be perfectly acceptable to most people, and is niche CB Performance is trying to fill.

123 ignition is trying to do this as well, but part of the issue is how much stuff is trying to be crammed under a very small distributor cap. The larger bodied aftermarket distributors have a lot more space by way of comparison.

What most guys really need is the old, dead reliable, domestically produced Mallory Uni-Lite with a locked out advance mechanism tied to a CB Black Box (with an updated software package, written for something newer than Windows 95, or whatever it is).

The Magnaspark is reputed to be pretty darned close.

Last edited by Stan Galat

Totally agree about the small diameter cap of the VW units. It makes arcing and carbon a definite thing rather than a non-issue. Especially since some of us routinely rev way past the 5000 or so rpm they were designed for.

You're right Stan, it's not the distributor itself, so much as the advance mechanism AND the electronics combined that make the whole affair shoddy. It doesn't have to be this way, but VW guys are CHEAP. And so it is.

Last edited by DannyP
@R Thorpe posted:

Thank you Eric, what I wanted to know and was not clear about is the method of assigning the spark I believe that the Pertronix is a Hall effect device basically a revolving magnet. I wanted to know if the Magnaspark was the same. I have the Magnaspark but I’ve seen a test where the Pertronix is all over the place at higher rpm. The test was on the 123ignition website, obviously it’s dizzy was very stable.

Mine was plus/minus 5 degrees at 3000rpm. That's a variance of ten degrees, or almost 50% of the range of the advance, MONUMENTALLY unacceptable.

Seems to be a fair amount of hostility towards Pertronix...my stock ($100) unit has about 6000 miles on the clock and has an ideal mechanical advance curve for my motor..it is +1 /- 1 (crank) degree !

I would look at the distributor drive gear (lot's of potential problems there) and the crank/cam mechanical interface (0-lash)...and then take a look at the push-rods (fully 30% longer than an LS-1 rod)...and puny in comparison!

A couple of years ago a guy in Germany showed me his laser-driven crank trigger accurate (he said) to 1/1000 of a degree . That's neat-that's-nice, but he had no idea how the 4 cams in his motor synchronized with that

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