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Date:         Sat, 7 Jul 2001 00:32:31 EDT
Reply-To:     FrankGRUN@AOL.COM
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Frank Grunthaner <FrankGRUN@AOL.COM>
Subject:      A new Adventure on the way to the Audi 2.0 Turbo - or pulling
              gears
Content-Type: text/plain; charset="US-ASCII"

I have had a new adventure (on the scale of my varied stimulations) and found an intriguing solution to a very difficult PIA problem, as I work my way through the hardware manipulations required to complete the Audi 2.0 Turbo project.

The problem: I'm switching to an all Saab/Bosch engine management system for engine and turbo control. This means LH-Jetronic ECU and fuel injection and the Saab APC knock-based control of turbocharger boost pressure and Saab ignition. As part of the Saab approach to detonation control, they use a distributor with Vacuum advance and retard, and no centrifugal advance. The Audi 3A engines (despite the erroneous notation on the EKTA) use a non-advancing distributor (knock sensor controlled ignition as per the CIS-E, Digifant and Motronic engines). I therefore wanted to make a Vacuum advance/retard only distributor compatible with the 3A engine. This Audi distributor uses a very large engaging gear (about 1/3 larger diameter than the regular VW counterpart) and a larger entry port for inserting the distributor into the engine. The VW CIS distributors have the necessary Hall ignition, but include both centrifugal and vacuum advance and a too small gear. The obvious solution, swap gears between the Audi and VW distributors! The manuals say: "Drift out (whack with a hammer and punch) the locking cross-pin and remove the gear from the shaft" Well it wouldn't come off!

I whacked and I whacked. I went through (means badly mangled) four Craftsman pin and center punches (love that guarantee - had to get the wife to exchange the second set) and still my sweaty reflection could be seen in the unmoving surface of the drift pin. After several shaking defeats (evidenced by the painfully swelling discolorations of too many of my smaller appendages) I took stock of the situation and went off in search of a machinist with the proper tools, level of experience and fully functioning digital subsets. Well, four of Pasadena's finest looked at them and said "those are like VW parts" and sent me on my way. One confident wizened fellow announced he couldn't get to it then, but they would be ready by noon the next day. Later I noted that his pinkie was absent on the right hand. Well, the next day soon became 7 days later with 5 successive one day excuses. On the seventh day, he announced (for the PC conscious please note I'm only reporting here) "Those pins are a real bitch. I've heated and cooled the shaft ... etc". You know, excuses. Then he said, "So I've sent them to a VW machinist (!!!) and they will be back tomorrow!" On the day after the morrow, he said "He just sent them on to a VW machinist (!!!) who specializes in distributors, they will be back tomorrow!" Then the exciting breaking story, "He has one of them out!, they will be ready tomorrow!"

Well to truncate this report, yesterday, he asked me to come and get these G...DD...M things the H.. out of here (trying to keep this clean). I picked them up, and clearly progress had been made ... the surface of the end of one of the pins was marred.

I then called Tectonics who had said, "just pound 'em out!" who now said, "Well I'd drill them out. Start at 1/8 inch bit then slowly work your way up to 5/32 then punch 'em out". He went on to observe that the pins were tool steel, and I should get a handful of high quality bits and prepare for a weekend worth of drilling.

I recounted my tale of woe to one of my trusty JPL machinists (with some minor embellishment) in a blatant attempt to solicit his professional assistance. Whereupon he said, "I'd plasma arc the damn thing!"

The solution: Well he sent me off to a little shop in an industrial park/getto in Irwindale. I showed the fellow my pieces. He asked a set of surprisingly well informed questions about the metallurgy and engineering of the gear and shaft system (and how much money and time I had), and announced he would give it a try, but for a litany of reasons there were no guarantees. Today at noon he called and announced that they were out and that would be $20 per pin please!

The wonder: What he did! He used a hollow electrode setup to strike a highly confined Nitrogen arc to rapidly cut the metal away (similar to a plasma torch). He calls it a metal disintegrator beam (!). He used a square cross-section electrode to cut through the 4 mm pin along its 15 mm length. Then pushed the remaining pin casing through! This thing cuts through hardened tool steel like butter, but there are no burrs or even discolorations on the inside of the gear or shaft hole. Amazing! Wow!

Oh, well as you can sense, I had a good time!.

His Name is Jim, his business is:

Bradley's Broken Tool Removal Service 5277 N. Vincent, #40 Irwindale, CA 91706 (626) 969-9565

Sorry for the length, hopes this helps someone else as much as it did me,

Frank Grunthaner


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