changing the original M70 spark plug boot

[shogun]

changing the original spark plug boot from a German forum regarding M70/S70 ignition wires, seems in most cases the long boot going to the spark plug is the problem, the resistor inside the long boot get’s bad over the years, German text
Beim M70 werden Zuendkerzenhersteller 5000-OHM 12121710707 benoetigt. Ich mochte beim S70 Motor die Zundkerzenstecker wechseln. Ist es wirklich so aufwendig, wie es in der Original BMW Reparaturanleitung steht ? Laut dieser braucht man hierzu mehrere Spezialwerkzeuge....Lt. dem aktuellen BMW Ersatzteilkatalog finde ich folgende Teile, kann mir jemand sagen,ob das so vollstaendig ist + warum 3 Teile ausgewiesen sind:
Kerzenstecker. 12121710707 , Isolierhulse 12121736142 , Rundstecker 12121705656
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Zuendkerzenstecker Bosch / Bremi mit 5KOhm Innenwiderstand. Im Laufe der Zeit zersetzt (oxidiert) der im Kerzenstecker enthaltene Metallfilmwiderstand sich und der Zuendstrom wird zu schwach. Das Wechseln der Kerzenstecker ist denkbar einfach, solange die Kupplungshuelse noch fest mit dem Kabel verbunden ist. du schneidest das Gummi des Kerzensteckers am oberen Ende vorsichtig auf, damit die Keramik freiliegt. mit einem kleinen Hammer nun den oberen Teil der Keramik zerschlagen, bis die silberne Kupplungshuelse freiliegt. Die Kupplungshuelse kann nun mit einem Dorn entriegelt und abgezogen werden. Der Neue z.B. Bremi / Bosch Kerzenstecker wird nun am Kabeleinlass mit etwas Fett oder Vaseline geschmeidig gemacht. Nun einen kleinen Schraubendreher am Kabel entlang in die Huelse einstecken und durch das Kabelloch des Kerzensteckers fuehren bis er hoerbar einrastet. Hierzu gibt es ein Spezialwerkzeug, eine Ahle welches das Zuendkabel umschliest und auf der Kupplungshuelse aufsetzt.

TRANSLATION: The M70 requires spark plug boot 5000-OHM is p/n 12121710707. I would like to change the spark plug boot on the S70 engine. Is it really as difficult as it is described in the original BMW repair manual? According to this one needs several special tools ....
Accdg to the current BMW spare parts catalog, I find the following parts, can someone tell me, if this is so complete + why 3 parts are shown: spark plug boot 12121710707, Insulating sleeve 12121736142, Round connector 12121705656
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Reply: You will need spark plug boots Bosch / Bremi with 5KOhm with internal resistance. Over time, the metal film resistor contained in the plug connector decomposes (oxidizes) and the ignition current becomes too weak.
Changing the plug connector is very easy, as long as the coupling sleeve is still firmly connected to the cable. Carefully cut the rubber of the plug boot at the top so that the ceramic is exposed. Smash the upper part of the ceramic with a small hammer until the silver coupling sleeve is exposed. The coupling sleeve can now be unlocked and removed with a mandrel. The new e.g. The Bremi / Bosch spark plug connector is now made flexible at the cable inlet with a little grease or Vaseline. Now insert a small screwdriver along the cable into the socket and guide it through the cable hole of the plug boot until it clicks into place.There is also a special tool for this purpose, which wraps around the ignition cable and attaches it to the coupling sleeve.
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The defective spark plug boot is now replaced. I bought the BERU tool EFS7 (introductory probe), so that you get the cable including the detent sleeve quite well into the boot. The engine is now running well again even at low speeds, unbelievable what effects a defective spark plug connector can have ... I have modified the tool handle by grinding a hollow line, so that the cable can run through better ....
picture below of the spark plug side and the distributor side, I cut an original Bremi open. The genuine spark plug boot/socket is quite expensive, for example BREMI 13226/5 = 12121710707 regular price about $35.00/piece.
Alternatively one can have from me the aftermarket ignition wires for M70/M73

[shogun]

here additional pics of the crimp on round connector on the original Beru, Bremi,BMW cable, also available online and/or from BMW, Plug Sleeve, ignition system BERU # RHB 001 ,BMW # 12121705656 ,Bremi # 13206/13 , Herth & Buss # 50 262 255 https://www.oldtimerbedarf.de/BERU-R...ungen-13206-13

and the Beru tool EFS7 , quote: Beru Mounting Aid Tool (Beru Ref No. 0.890.300.002), The mounting aid EFS 7 is specially designed for the installation of M3 threaded sleeve or Ratchet sleeve into Spark Plug Connector assuring a quick and exact fit on to the ignition wire https://www.kingsbornewires.com/product-p/efs7.htm pretty expensive with >$30, a small screwdriver will do the same job.

[shogun]

Technical Information Sheet no. 5
here detailed 33 pages info on the various BERU ignition connectors https://web.archive.org/web/20190615...tot/TI05_e.pdf on page 8 for example BMW connectors for sawtooth contacts for spark plug side and page 9 angled ones. Page 11 shows Tip when installing in BMW with pulse timer for the 4 or 6 cylinder versions, excerpt:
This brochure explains how you can repair or totally replace ignition lead sets reliably and professionally with the help of the Beru ZAZ 3 workshop range. The range enables workshops for the very first time to employ the same attachment techniques used as standard in mass manufacture.

Page 11 shows pics + instructions / tips when installing in BMW with pulse timer/cylinder identification sensor/donut for the 4 or 6 cylinder versions. On 4 cylinder engines an induction timer is fitted to the ignition cable of the 4th cylinder, on 6 cylinder engines this is fitted to the ignition cable of the 6th cylinder. When replacing cables, save the time-consuming and costly work of refitting an ignition cable with a built-in pulse timer. Your customer will be grateful to you for the roughly thirty pounds he saves. Just remove the defective cable only.
Unscrew the ignition distributor plug on the new Copper Cable (spray with Beru installation oil).
Drill 8 mm hole on the pulse timer (turn drill by hand). The ignition cable with the M3 connection can now be pushed through the pulse timer. Now lubricate the ignition cable with installation oil. Finally, screw on the ignition distributor connector of the Copper Cable.

the sawtooth/woodscrew type connection on spark plug side works same/similar way, maker of such spark plug booths with woodscrew type once replled to me:
To properly install the rubber boot spark plug side, oil the end of the ignition cable, then put the cable into the boot and screw it in until resistance is felt. There is no need to remove the outer cover plastic piece from the spark inner side rubber.
But the way kce1900 describes it below is the best way. Separate outer cover from inner part of the boot and screw the ignition wire on the woodscrew.

[kce1900]

I've had two cables with an electrical resistance trending towards infinity. Both had screw-on plugs. In one case, the plug was broken internally and in the other case it was simply a bad connection between cable and plug. In theory, it should be possible to unscrew the cable from the plug with the rubber boot installed. However, the cable is quite flexible and twists very easily. Furthermore, the boot sits very tightly on the cable. Most of the torque applied to the cable is therefore wasted by twisting cable and boot.

I found it better to remove the boot first. This allows me to grab the cable as close to the screw as possible. The two most important things for this job are lubrication and patience.

I injected WD-40 Silicone Spray between the boot and the plug. Next, I inserted a small screwdriver from the back until I hit the edge of the plug. Then I simply applied pressure and at the same time tried to push the front of the rubber boot towards the cable. If you continue to apply pressure and work the front a bit, the plug will eventually move at glacial speed. Literally. Typical glacier speed is 1 m/day or 0.7 mm/min which is roughly what this plug seems to do. Ok, maybe it's twice as fast. However, patience and lubrication remain key.

Once you have the plug out, you can unscrew the cable. For reassembly I screwed the cable into the new plug before installing the boot. In order to know for sure how far the cable needs to be screwed in, I used a bit of tape to mark the required depth (about 34 mm in my case, see picture).

Pushing the rubber boot over the cable is straightforward, but it requires more lube and more patience.

The procedure for removing the angled connector is similar. Shogun has posted a description with pictures here.