Some bits arrived.
Not sure I really believe they're genuine resistorless bosch plugs given the forum wisdom (circa 2006!) on 116.org that such can only be got from Herr Benz's Private Stash... but that's what they claim to be.
Some ignition leads. Yes of course I stuffed up and got the wrong ones (for D-Jet cars with the modern female distributor contacts). The plug ends are also the run-of-the-mill sparkplug type. Not an issue these days I guess since even "old style" plugs like I got, ngk bp5es etc. should all come with the little push on barrel nuts fitted. Really I only need to sort out spark to the point that either the engine starts or I can eliminate lack of spark as a cause, so I wasn't too bothered. The correct distributor terminals are only an AliExpress order away and I have access to whatever crimp tools I'd need to rework them, should I need.
I was curious to see what sort of resistances the new and the old leads had. From teh googelz I expected the Eagle leads to be around 2kR, so theoretically high enough to comfortably not melt the coil without resistor plugs [ref for this is a porsche 924 I ran on a crane hi6 cdi for a year which had no coil or distributor issues. Crane recommends "as near zero resistance as possible" to get multispark etc. So I had custom TopGun leads at about 300R, noisy plugs and even dug the wire out of my dizzy rotor and filled it with copper to drop iirc the 100R in there. The coils are virtually the same between the two cars and the ignitiors look like dead ringers: given 924 was a 1978 release I'd be surprised if Bosch was building wildly different ignition circuits for transistorised distributed systems in K-Jetronic cars at the same time]. From teh metal rfi shields on the Beru leads I expected 5kR. Findings summarised below:
Can literally read the length of the lead in resistance. At least relatively.
It was a lot harder to make a multimeter connection to the Beru leads' plug ends. And sometimes they seemed friable, so broken conductors looked likely in #5 and #7. I pulled the leccy tape off #s 1 & 3 to see how bad the boots were. Didn't realise the boots just sheath the ceramic insulators at the back of the metal. Had a laugh at wrapping 4mm of porcelain in 400um of pvc to "prevent shorts" at 20kV or whatever...
While I picked off the crusty burnt and oil hardened rubber (had already decided to heatshrink for looks) I noticed I could easily turn the lead in the boot...
I had no idea they were screwed on!
Suddenly it all made sense.
I *did* actually find some dodgy insulation near one plug boot (#2), so I pulled that one apart too. Cleaned them all, added heatshrink and reassembled:
LGFFA!
Retested and connections were still non-trivial to make, but solid once found. Decided to employ an M4 screw as contact scrubber with some rp7.
And that's how I discovered this:
This is #8. Do you see it? No? Neither do I!
This is #7. Now you see it, right? Pretty obvious? It sure is when you jam a screw in there and need a pair of pliers to pull it out against that spring clip tension, but you get to lucky last and the screw falls all the way in under gravity alone and right back out again when you tip the boot!
So a multimeter is NOT all you need to check ignition leads, and I'm glad I've such a fetish for abrasively cleaning electrical contacts [refer to file and sandpaper work on starter in previous posts], otherwise I never would've twigged that the only force needed to get #8 on and off the plug was due to the rubber grommet on the plug insulator.
Now my quandary is this: I can get a genuine but used (pair of) Beru leads shipped from Germany for $100 or so. Possibly one of them has a good contact on the boot. But maybe takes a month. I can get a new lead kit for a 6 cylinder locally for about the same, slight gamble on contact type (did they change in '76? Did they ever come Kjet?). Or I can get a full set (correct one this time) of the same Eagle ones for $140. But probably still ~1kR, modern plug boots etc.
Infuriating since I only really need one Beru suppressor plug boot. The lead is fine. Stay factory spec. etc. But OTOH all I need right now is to get the car in the garage, so even just using one odd lead out from the unsuppressed Eagle leads should do. I guess I'll probably order them (p/n 7817, BTW for posterity, to suit post '76 v8s, the early cars use 7821. Anyone wants a set message me. Resistances in the photo!)
). I even copperslipped everything. Leaving nothing to chance like.
