my rotor is bigger than your rotor

[Peter Schulz]

Scott Mockry's opinion:
http://www.sjmautotechnik.com/20vboost.html#rotor

"The Bosch catalog shows the INCORRECT distributor rotor (Bosch 04170 or
the 1 234 332 350 R1) for this 20V Turbo application. This 04170 (1 234 332
350 R1) rotor has a wider electrode tip measuring 0.710  inches (~18mm).

The correct Distributor Rotor is the Bosch 1 234 332 414 R1 (Audi 054 905
225) which has a narrow electrode tip measuring only 0.432 inches, (~11.0mm). "

-Peter

At 09:35 AM 6/11/2002 -0400, Brandon Hull wrote:
>I guess it's part of the nature of email lists that issues are raised and
>recede in their seasons, leaving behind vestiges of institutional memory
>and articles of faith.  It's worth a reminder of the origins of the
>"narrow rotor" doctrine.
>
>So:  circa 1997:  Jeff Donnelly's famous "dragon wagon" was a fire
>breathing track animal with a 400HP 3B engine built for him by Lehman, via
>Hoppen motorsports.  He suffered a catastrophic engine failure which
>Lehman traced back to a distributer-caused misfire.  They shipped the
>engine back to germany, rebuilt it at their expense, sent it back to Jeff
>with the stern warning to never use anything but the factory distributer
>and ignition wires.  At about the same time, Alex Neckas was dealing with
>misfire issues on his very modified 3B installed in his 4Kq racecar.  He
>came to the same conclusions, namely that at high rpm, the later rotor was
>just wide enough to cause a spark to arc to the next ignition terminal
>prematurely.  Depending on what the cylinder was doing at the time, this
>could be a Bad Thing.  (eg exhaust stroke, no prob; compression stroke? V.Bad)
>
>So, as for me and my house, we will use the narrow rotor...
>
>Brandon H
>e//S2
>
> >
> >
> > Don't quite agree, Brett:
> >
> > First of all - Audi/Bosch never really intended the
> > distributor rotor on the 3b be replaced on it's own - the whole unit is
> supposed
> > to be replaced - plastic gear and all.
> >
> > Replacement distributors come with the narrow rotor - which
> > challenges your line of thought, too - if there was no difference, then
> > Audi/Bosh would then have stopped making the additional part
> number...parts
> > variation just increases costs for suppliers and manufactures
> >
> > Scott Mockry recommends the narrow, rotor, too.
> >
> > You are probably correct in that a mildly tuned engine can
> > run with the"wider" rotor - however - for the relatively minor price
> > difference
>  - I'm  not willing to risk it...I'll look for $ savings elsewhere.
> > YMMV
> >
> > -Peter
> >
> >
> >
> >
> > At 03:17 PM 6/10/2002 -0400, you wrote:
> > >At 10:17 AM -0400 6/10/02, Peter Schulz wrote:
> > >
> > >>  but of course the rotor was the wrong type ( wide
> > >>contact)  luckily I ordered a few of the correct rotors from ROd at TPC.
> > >
> > >The whole wrong versus right rotor is a bunch of horse
> > whooey...IMHO :-)
> > >
> > >I've been running the "wrong" rotor for several years and around 60k
> > >miles, with two different chipped ECUs...and I flog the bejezus out
> > >of my car.  Running stage III+ now, pretty aggressive chip.
> > >
> > >There's the real-world evidence; the thinner rotor has been (for the
> > >most part) "unavailable" for years....and there are probably hundreds
> > >200q20v's running the "wrong" rotor...again for years(I would guess
> > >that a survey of the list would find the majority, at least 2/3rds,
> > >have the wider rotor installed.)  3B engine kabooms are pretty
> > >rare...the only one I've heard of was Sarge, and there were other
> > >issues involved there...like the clouds of smoke on startup for a
> > >couple days before the engine chewed itself on the highway.
> > >
> > >Personally, I'll be following the Bosch guidelines...I see no point
> > >in spending the extra time, money, or effort on finding the "thin"
> > >rotor.
> > >
> > >Besides, "Wider is Better", right? :-)
> > >
> > >Brett
> > >--
> > >----
> >
> > Peter Schulz
> > 1990 CQ
> > 1991 200 20v TQW indigo mica
> > 1991 200 20v TQW titanium grey
> > Chelmsford, MA USA
> > peschulz at cisco.com
> >
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> >