123 Distributor Install - post-mortum, MPS was “bad”? But it isn’t? Options

[FlacaProductions]

Many of you followed and helped as I attempted to install a bluetooth 123 distributor in my 74 2.0 here:
http://www.914world.com/bbs2/index.php?sho...=368374&hl=

I can’t thank everyone enough for all of their input.

Car originally ran pretty well but I was installing the 123 to fix a running-warm situation due to a failed vacuum can on the stock distributor. (0231174011 with Pertronix Igniter II) MPS was a clearly opened/modified 0280100041 (done by PO).

The install proved difficult/frustrating (would NOT start) and everything from a bad 123 unit to not accurately finding TDC was suspected.

Luckily, I had recently picked up a stock/unopened 0280100043 MPS and after installing and re-installing the 123 multiple times, confirming TDC, etc, etc, I was desperate.

I know you’re not supposed to just “throw” parts at a problem, but in a last-ditch effort I dropped in the “new” 043 MPS and it immediately fired up. Runs GREAT.

This is where things get confusing:
The 041 tests ok out of the car - 15lbs of vac for 30 mins and I get 95 ohms across 7 and 15 and 345 ohms across 8 and 10.

The 041 had obviously been opened and I assume modified/repaired - but again - it ran fine in conjunction with the stock distributor w/Pertronix.

Why would it run just “fine” (outside of the conditions caused by the failed distributor vacuum can) with the stock distributor/041 MPS and yet not even come close to starting with the 123/041 combo, and then run great with the 123/043 setup?

Now i’m on to dialing in/playing with curves - I’ve found really nice performance with one that Pete Stout posted. Even though his is a 1.8, it made a noticeable difference to the point where my nephew remarked that it was really “snappy” now.

Other than that, I think i’m going to pop the 2 female pins out of the wiring harness that the 123 yellow and white wires plug into and shrink wrap them for a more solid connection. That seems like a weak link.

Additional questions:
- does my original distributor with Pertronix have value to anyone? The Pertronix itself is $100+ new. I can’t see needing to keep it as a backup when the vacuum can has tested bad and the 123’s are seemingly bulletproof once properly installed.
- does my 041 MPS have value? Should I open it up or have it tested and potentially rebuilt? As it sits, it totally immobilizes my 914 when installed. Is there potential to have it turned into a viable backup?

Again - thanks to The World. I learned a lot during this process and could NOT have gotten to the other side without all the input here!

[technicalninja]

I'd open it up for the experience ALONE!

I'd try to determine what failed and why.

Ninja proverb:
Hunt the ROOT, find it, and, if possible, come up with improvements.

I'd look at that diaphragm under magnification.

[Superhawk996]

I'd open it up for the experience ALONE!

(IMG:style_emoticons/default/agree.gif)

I’ve got one open at the moment.

Bad diaphragm being replaced. But I also found a stripped 4mm screw that holds and seals the diaphragm retaining ring. Someone was in here before (even though epoxy plug over adjustment screw was intact) and thought a 4mm screw needed about 100 lb-ft of torque? Stripped at factory? (IMG:style_emoticons/default/confused24.gif) There’s no telling what you might find.

Awaiting 4mm Heli-coil.