200q20v Digest, Vol 146, Issue 4

[Jay Kempf]

Eric, Bernie, all:

I know, EDM, tungsten, don't try it with a hand drill in a tight spot, 
pull flywheel... It was just out so I really didn't want to go back 
through all that...

So here's the deal. The pin location was pretty obvious with it's 
tangent right on the recess machined into the flywheel. That recess 
happened to be just about 16GA deep and I happened to have some 16GA 
stock lying around. So I figured if could land an edge of sheet metal 
right on the centerline of the pin right on the recess to locate it and 
fasten it in there somehow I had a chance. This timing pin is a 
reference signal, not like the high speed signal that the teeth of the 
starter ring give. One pulse per rev distinct. Then the whole thing is 
handed over to the hall sensor while the car is running. So I figured it 
wasn't a high tolerance on location. Just as a reference in a 12" circle 
let's say that's somewhere just over 3 feet of circumference so about .1 
inch of circumference per degree. The pin is/was 5mm. So that means I 
need to be within close to .125 say to make sure I was on the same 
degree of location. Not a problem. So I made a little piece of 16 Gauge 
1.25 x about .5 and bent up one end about .5 high. Drilled a couple 
3/16" holes in the longer tab. I clamped it up there with a magnet and 
MIG spot welded through the holes. What did I have to lose I could 
always grind it off and start over. I swung the crank through to check 
clearances and rechecked all timing marks and checked the depth of the 
sensors and clearances. I actually had to shim the RPM sensor using one 
crush ring under the head to get about 1mm.

Car started on about the third turn like it had never stopped. Need to 
clear codes again and pull fuses to zero and remap everything. But the 
old starting hesitation is gone and it was sputtering a bit but it 
hasn't run in a long while at this point. So I can dial from here

Lesson learned. No one could ever do that to a customers car but this is 
a toy for me so what was there to lose. Learned a lot about the ignition 
and fuel system inputs and outputs. Now I want one of those little micro 
usb bore scopes and the same sort of oscilloscope for doing diag.

Thanks to all that lead me along the path to getting this thing sorted. 
What I know now is that I have touched every single part of the system 
that I was worried about and it is all now close to perfect and 
serviceable. So now I can have a little more confidence that this thing 
will be reliable moving forward. Still much to do but much has already 
been done.

Oh and one more PS about these cars. I have never ever glued a rotor 
onto the distributor shaft. I have had this car for 15 years at this 
point I think, and always used the wrong part number too wide rotor 
because I didn't know back when I first got the car. Never been any 
issues so I never changed it when I found out. I am amazed at how the 
OEM parts have plummeted in price mostly on ebay for these cars. I have 
mostly chewed through my NOS box of OEM parts that I had lying around 
for 10 years. Have some more things to go through before paint to get 
this thing back to it's glory. But happy to see it moving under its own 
power again.

regards,

jfk

802 272 5868


On 5/10/2017 3:00 PM, 200q20v-request at audifans.com wrote:
> Jay,
>
>   
>
> Just went and looked at the flywheel I recently replaced due to ring gear
> tooth missing. The backside of the hole is covered by the ring gear, so
> punching through is not an option! Personally I would pull the flywheel.
> Yes, I know how much of a PITA that is, just did it!
>
>   
>
> You'd probably have better luck finding someone with a Bridgeport or good
> drill press and bits that will work with a hardened pin! (Hand drill is a
> little dicey in that situation!)
>
>   
>
> As for welding a pin/plate in.. You'd have to be dead on, not much tolerance
> clearance wise to the sensor.
>
>   
>
> Nice to see Audifans is back up! Pretty much figured out that the run of the
> mill issues receive no attention on some of the other forums. Only get
> responses about big turbos and pie in the sky issues!
>
>   
>
> Eric
>
>
>
> ------------------------------
>
> Message: 2
> Date: Tue, 9 May 2017 16:45:07 -0700
> From: Bernie Benz <b.benz at charter.net>
> To: "Eric Huppert" <ehuppert at hvc.rr.com>
> Cc: 200q20v at audifans.com
> Subject: Re: Drilling pins
> Message-ID: <9BCD47DF-AF28-4C1E-B097-F92DEE636545 at charter.net>
> Content-Type: text/plain; charset=windows-1252
>
> Even with the fly wheel out, still the only way to remove it easily is with an EDM machine, Eletromagnetic Discharge Machine, if it can’t be drive thru.
> Audi wasn’t smart enough to leave a clearance hole in the ring gear, which had to be timed to the pin hole anyway.
> Bernie
>
> On May 9, 2017, at 4:25 PM, Eric Huppert wrote:
>
>> Jay,
>>
>> Just went and looked at the flywheel I recently replaced due to ring gear
>> tooth missing. The backside of the hole is covered by the ring gear, so
>> punching through is not an option! Personally I would pull the flywheel.
>> Yes, I know how much of a PITA that is, just did it!
>>
>> You'd probably have better luck finding someone with a Bridgeport or good
>> drill press and bits that will work with a hardened pin! (Hand drill is a
>> little dicey in that situation!)
>>
>> As for welding a pin/plate in.. You'd have to be dead on, not much tolerance
>> clearance wise to the sensor.
>>
>> Nice to see Audifans is back up! Pretty much figured out that the run of the
>> mill issues receive no attention on some of the other forums. Only get
>> responses about big turbos and pie in the sky issues!
>>
>> Eric
>> ***********************************