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furgo
Samba Member
Joined: September 06, 2016
Posts: 944
Location: Southern Germany
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 Posted: Sat Dec 09, 2017 8:37 am Post subject: Ignition wiring refresh |
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After having restored the distributor a while back, I'm going through the ignition wiring now. I thought I'd document part of it here and ask a few question in case someone knows the answer.
Essentially:
• The wires themselves seem to be in good shape. They're Beru ones, with PVC insulation and I believe tinned copper core. I could think they were replaced not too long ago by a PO. I think I'll keep them. The other alternative is to get a roll of new ignition wire, but one of the ends is crimped, which cannot be done by a hobbyist with regular tools.
• All black rubber caps were petrified and needed to be replaced.
• Two out of four red rubber caps were missing.
• Some of the bakelite spark plug connectors were chipped at the end where they meet the wire, needed replacement.
• The resistance on each one of the spark plug connectors was spot on 1 kΩ.
Here's an overview of the parts for one single wire:
On my bus
On the microfiche
| Code: |
Fig. Part # (VW) Part # (Bosch) Designation Remarks Qty
===== ============= ============== ===================== ======================= ===
4 311 905 429 A n/a Protective cap 1
14 111 905 427 n/a Connector, ign. leads 6
16 311 905 429 A n/a Protective cap **Alt. 111 905 429 B 5
18 311 905 429 A n/a Protective cap **Alt. 311 905 443 4
*(18) 311 905 444 A n/a Protective cap Red rubber cap 4
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
(19) 113 035 255 A 0 356 100 014 Spark plug connector 62 mm, cylinder 1, 3 2
(19) 021 035 255 G 0 356 100 030 Spark plug connector 109 mm, cylinder 2, 4 ***2
-----------------------------------------------------------------------------------------
(19) 113 035 255 A 0 356 100 014 Spark plug connector 62 mm, cylinder 1, 3 2
(19) 021 035 255 0 356 100 023 Spark plug connector 85 mm, cylinder 4 1
(19) 021 035 255 B 0 356 100 027 Spark plug connector 98 mm, cylinder 2 1
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
20 122 905 449 A n/a Protective cap Alt. 111 905 449 4
* Not depicted on microfiche, wrong fig. no.
** They were on my bus, but not listed on microfiche. Fit well, viable alternative.
*** Corrected, original microfiche said "1".
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Part identification
Note the wrong figure number on the microfiche for the (*18) red rubber cap (or is it silicone?), which does not actually appear in the drawing. Also note the two possible configurations of spark plug connectors.
All this raised a few questions:
• Was the *18 red rubber cap part of the original ignition wires set? I'm asking because the new sets I've seen available don't seem to include it. Or is there something else that replaces their function (keep humidity at bay)?
• Why were there two configurations for spark plug connectors? I'm not near the bus right now, but is there a particular reason for the configuration where there are two different lengths for cylinder 2 and 4 to exist? Is the height of the engine tin on both sides not the same? Or is there additional clearance needed in one of the two sides?
• What type of ignition wires are folks using? Are silicone-insulated wires an obvious upgrade in terms of durability?
• Alternatively, are there any ignition wire sets that are generally recommended for FI busses? I've seen the Bosch 09-171 set for Type 4 engines being mentioned in some places, but I don't know if it's still available. In fact, at least in Europe I couldn't find it anywhere.
_________________
'79 Westy, P22 interior, FI 2.0 l Federal, GE engine (hydraulic lifters)
Decode your M-Plate |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21512
Location: Oklahoma City
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| Posted: Sat Dec 09, 2017 11:46 am Post subject: Re: Ignition wiring refresh |
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| furgo wrote: |
After having restored the distributor a while back, I'm going through the ignition wiring now. I thought I'd document part of it here and ask a few question in case someone knows the answer.
Essentially:
• The wires themselves seem to be in good shape. They're Beru ones, with PVC insulation and I believe tinned copper core. I could think they were replaced not too long ago by a PO. I think I'll keep them. The other alternative is to get a roll of new ignition wire, but one of the ends is crimped, which cannot be done by a hobbyist with regular tools.
• All black rubber caps were petrified and needed to be replaced.
• Two out of four red rubber caps were missing.
• Some of the bakelite spark plug connectors were chipped at the end where they meet the wire, needed replacement.
• The resistance on each one of the spark plug connectors was spot on 1 kΩ.
Here's an overview of the parts for one single wire:
On my bus
On the microfiche
| Code: |
Fig. Part # (VW) Part # (Bosch) Designation Remarks Qty
===== ============= ============== ===================== ======================= ===
4 311 905 429 A n/a Protective cap 1
14 111 905 427 n/a Connector, ign. leads 6
16 311 905 429 A n/a Protective cap **Alt. 111 905 429 B 5
18 311 905 429 A n/a Protective cap **Alt. 311 905 443 4
*(18) 311 905 444 A n/a Protective cap Red rubber cap 4
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
(19) 113 035 255 A 0 356 100 014 Spark plug connector 62 mm, cylinder 1, 3 2
(19) 021 035 255 G 0 356 100 030 Spark plug connector 109 mm, cylinder 2, 4 ***2
-----------------------------------------------------------------------------------------
(19) 113 035 255 A 0 356 100 014 Spark plug connector 62 mm, cylinder 1, 3 2
(19) 021 035 255 0 356 100 023 Spark plug connector 85 mm, cylinder 4 1
(19) 021 035 255 B 0 356 100 027 Spark plug connector 98 mm, cylinder 2 1
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
20 122 905 449 A n/a Protective cap Alt. 111 905 449 4
* Not depicted on microfiche, wrong fig. no.
** They were on my bus, but not listed on microfiche. Fit well, viable alternative.
*** Corrected, original microfiche said "1".
|
Part identification
Note the wrong figure number on the microfiche for the (*1 red rubber cap (or is it silicone?), which does not actually appear in the drawing. Also note the two possible configurations of spark plug connectors.
All this raised a few questions:
• Was the *18 red rubber cap part of the original ignition wires set? I'm asking because the new sets I've seen available don't seem to include it. Or is there something else that replaces their function (keep humidity at bay)?
• Why were there two configurations for spark plug connectors? I'm not near the bus right now, but is there a particular reason for the configuration where there are two different lengths for cylinder 2 and 4 to exist? Is the height of the engine tin on both sides not the same? Or is there additional clearance needed in one of the two sides?
• What type of ignition wires are folks using? Are silicone-insulated wires an obvious upgrade in terms of durability?
• Alternatively, are there any ignition wire sets that are generally recommended for FI busses? I've seen the Bosch 09-171 set for Type 4 engines being mentioned in some places, but I don't know if it's still available. In fact, at least in Europe I couldn't find it anywhere. |
A couple of things:
Silicone Versus PVC:
Tear resistance: PVC is much stronger than silicone
Heat and oil resistance and ageing: Silicone is much better than PVC
Dielectric Strength (insulating ability):
Red high temp cast silicone in general is about 47kV/mm
PVC cast/extruded insulation in general is about 11-15kV/mm
So silicone is a much better insulator, stays pliable longer and stands higher heat.
PVC however for most standard spark plug wires is a plenty good enough insulator. However with age and heat it gets stiff, tends to form cracks at bend areas and at high vibration.
Silicone coated wires...can get torn easier especially at the strain relief of the crimped on connectors. Once this happens...it can short to ground easily when the conductor is exposed.
Cost: Silicone is much more costly...probably about 2-3X.
You can crimp on new end connectors at home. This is just one example of available connectors. Virtually every style of connector is available somewhere on line.
https://www.summitracing.com/parts/tay-44409?seid=...gLAJvD_BwE
Generally they do not require anything special in a crimping tool. Ray |
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furgo
Samba Member
Joined: September 06, 2016
Posts: 944
Location: Southern Germany
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| Posted: Sat Dec 09, 2017 1:18 pm Post subject: Re: Ignition wiring refresh |
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| raygreenwood wrote: |
So silicone is a much better insulator, stays pliable longer and stands higher heat.
PVC however for most standard spark plug wires is a plenty good enough insulator. However with age and heat it gets stiff, tends to form cracks at bend areas and at high vibration.
Silicone coated wires...can get torn easier especially at the strain relief of the crimped on connectors. |
Perfect, great explanation and summary on silicone vs. PVC, thanks Ray!
| raygreenwood wrote: |
You can crimp on new end connectors at home. [...]
Generally they do not require anything special in a crimping tool. Ray |
I see this differently, though. The connectors on my ignition cable have definitely been crimped with a special crimping tool that a) has an opening of 7 mm that folds the connector wings into the insulation and b) presses a notch at the back of the connector that bites into the insulation for extra mechanical resistance against pull.
I've found other styles that could be used for attaching the distributor cap connectors without special tools, though: with a screw (similarly to how the spark plug connectors are attached), or by soldering them. Neither of them convinced me in terms of robustness.
As per the question of which set to use, a tip from a German forum member and this post here on The Samba has led me to consider the Bremi ignition cable set for the Type 4 engine:
_________________
'79 Westy, P22 interior, FI 2.0 l Federal, GE engine (hydraulic lifters)
Decode your M-Plate |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21512
Location: Oklahoma City
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| Posted: Sat Dec 09, 2017 1:57 pm Post subject: Re: Ignition wiring refresh |
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| furgo wrote: |
| raygreenwood wrote: |
So silicone is a much better insulator, stays pliable longer and stands higher heat.
PVC however for most standard spark plug wires is a plenty good enough insulator. However with age and heat it gets stiff, tends to form cracks at bend areas and at high vibration.
Silicone coated wires...can get torn easier especially at the strain relief of the crimped on connectors. |
Perfect, great explanation and summary on silicone vs. PVC, thanks Ray!
| raygreenwood wrote: |
You can crimp on new end connectors at home. [...]
Generally they do not require anything special in a crimping tool. Ray |
I see this differently, though. The connectors on my ignition cable have definitely been crimped with a special crimping tool that a) has an opening of 7 mm that folds the connector wings into the insulation and b) presses a notch at the back of the connector that bites into the insulation for extra mechanical resistance against pull.
I've found other styles that could be used for attaching the distributor cap connectors without special tools, though: with a screw (similarly to how the spark plug connectors are attached), or by soldering them. Neither of them convinced me in terms of robustness.
As per the question of which set to use, a tip from a German forum member and this post here on The Samba has led me to consider the Bremi ignition cable set for the Type 4 engine:
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Yes...they use a large open barrel crimper. But you do not have to do that. Virtually all of the connectors work like that. You can use a standard crimper for butt connectors and make two crimps about 1.5-2.0 mm apart and they are virtually indistinguishable from a factory wide barrel crimper.
Or you can buy a spark plug wire crimper.
https://www.summitracing.com/parts/tay-43390?seid=...gKs6_D_BwE
I have used this one or similar and it works great.
Also if you already have a nice ratcheting crimper from Eclipse, Luna, Paladin/Greenlee or any of the knock off brands....you can buy the factory style sparkplug crimping die.
https://m.ebay.com/itm/Eclipse-Crimp-Die-Set-9pk-3...SwofxUiImh
This one should fit most of the common ratcheting crimpers. Ray |
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Wildthings
Samba Member
Joined: March 13, 2005
Posts: 50337
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| Posted: Sat Dec 09, 2017 6:41 pm Post subject: Re: Ignition wiring refresh |
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I have a Snap On tool that does a tolerable crimp for the wires. Please note that the crimp just holds the terminal to the wire, it has very little to do with the electrical function of the wire otherwise. When need be I have made some very functional crimps with just tools like Visegrips or Channelocks, a special tool really isn't required, just some patience and care.
I have not seen a #18* boot in years, its purpose was to keep water away from the post on the spark plug. Guess VW and Bosch decided it wasn't necessary. Some other brands incorporate this boot into the design of their wires.
FWIW, with all the trouble I have had with Bosch electrical parts, I don't think I would buy a Bosch set of wires these days, even though I have not had a problem yet with Bosch wires. |
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ToolBox
Samba Member
Joined: January 27, 2004
Posts: 3439
Location: Detroit, where they don't jack parts off my ride in the parking lot of the 7-11
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| Posted: Tue Dec 12, 2017 10:01 am Post subject: Re: Ignition wiring refresh |
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| Wildthings wrote: |
I have not seen a #18* boot in years, its purpose was to keep water away from the post on the spark plug. Guess VW and Bosch decided it wasn't necessary. Some other brands incorporate this boot into the design of their wires.
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The SMP Intermotor wires are pictured in catalogs with the lower insulator.
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furgo
Samba Member
Joined: September 06, 2016
Posts: 944
Location: Southern Germany
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| Posted: Thu Dec 14, 2017 3:27 pm Post subject: Re: Ignition wiring refresh |
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I ended up ordering two of the long spark plug connectors (for cylinder 2, 4). It's a Bosch genuine part, and to my surprise, it's 1.4 kΩ instead of the expected 1.0 kΩ. I then looked up the specs for each one of the parts listed in the microfiche, and it seems that:
• The short spark plug connectors (cyl. 1, 3) are 1.0 kΩ
• The long spark plug connectors (cyl. 2, 4) are 1.4 kΩ
Here's the relevant part of the table with the two possible configurations of spark plug connectors, updated with the resistance value of each one of them.
| Code: |
Fig. Part # (VW) Part # (Bosch) Designation Remarks Qty
===== ============== ============== ===================== ============================= ===
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
(19) 113 035 255 A 0 356 100 014 Spark plug connector 62 mm, 1.0 kΩ, cylinder 1, 3 2
(19) 021 035 255 G 0 356 100 030 Spark plug connector 109 mm, 1.4 kΩ, cylinder 2, 4 ***2
-------------------------------------------------------------------------------------------------
(19) 113 035 255 A 0 356 100 014 Spark plug connector 62 mm, 1.0 kΩ, cylinder 1, 3 2
(19) 021 035 255 0 356 100 023 Spark plug connector 85 mm, 1.4 kΩ, cylinder 4 1
(19) 021 035 255 B 0 356 100 027 Spark plug connector 98 mm, 1.4 kΩ, cylinder 2 1
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
*** Corrected, original microfiche said "1".
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Spark plug connectors
I'm puzzled, though. Tbh, I can't quite quantify how much of a difference in spark the extra 0.4 kΩ make, but I had always thought that the four connectors were each 1.0 kΩ (at least they currently are in my bus, although they're a mix of manufacturers: Bosch, Bremi and no name).
_________________
'79 Westy, P22 interior, FI 2.0 l Federal, GE engine (hydraulic lifters)
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Wildthings
Samba Member
Joined: March 13, 2005
Posts: 50337
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| Posted: Thu Dec 14, 2017 3:30 pm Post subject: Re: Ignition wiring refresh |
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| I would doubt that the difference in resistance makes much of any difference at all. People commonly switch between resister and non resister plugs and have no problems. |
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furgo
Samba Member
Joined: September 06, 2016
Posts: 944
Location: Southern Germany
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| Posted: Thu Dec 14, 2017 3:36 pm Post subject: Re: Ignition wiring refresh |
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Might well be, although if it would have any noticeable effect on the spark strength, then the two back cylinders would have less current flowing during firing due to the extra resistance. I'm not an expert on high voltages, I'm just thinking out loud.
I should also add that the resistance value of either the 1.0 kΩ or 1.4 kΩ resistors is specified with quite a big tolerance of ±20%. Although all the ones I've measured so far were pretty much spot on 1.0 kΩ. Also to add to this, there is the series resistance of the rotor (5 kΩ).
_________________
'79 Westy, P22 interior, FI 2.0 l Federal, GE engine (hydraulic lifters)
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Wildthings
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Joined: March 13, 2005
Posts: 50337
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| Posted: Thu Dec 14, 2017 3:51 pm Post subject: Re: Ignition wiring refresh |
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| Think of a straight six engine with spark plug wires where the resistance is determined by the length of the wire. The 3 and 4 cylinder wires are significantly shorter and thus significantly lower in resistance then the 1 and 6 cylinder wires. V 8's can be the same way as the dizzy was usually at either the front or rear of the engine and often leaning off to one side or the other as well so some wires were much shorter than others. |
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furgo
Samba Member
Joined: September 06, 2016
Posts: 944
Location: Southern Germany
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| Posted: Thu Dec 14, 2017 4:08 pm Post subject: Re: Ignition wiring refresh |
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Very good point. Also a non-symmetrical (front vs. back spark plugs) resistance setup, then.
In our busses, assuming copper cables, I can think of these possible total resistance values for a single wire:
• Integral resistor on rotor and connector (non-resistor spark plug): 6.0 kΩ to 6.4 kΩ
• Integral resistor on spark plug only (resistor spark plug, rotor and connectors replaced with 0-Ω ones): 5 kΩ
• And for those who didn't replace the rotor and connectors when using spark plugs with resistor: 11.0 kΩ to 11.4 kΩ
So at the end of the day, the 0.4 kΩ most probably haven't got a noticeable effect. The difference in values simply surprised me initially, as I thought they were all the same (and in fact they were in my bus, but perhaps not originally so).
Finally, there's an interesting section on http://www.ratwell.com/technical/IgnitionSystem.html with measurements and spark plug voltage waveform variation during the firing event on a 0 Ω vs. 1 kΩ vs 5 kΩ rotor (scroll down to the "Which rotor" header, sorry, no direct link).
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'79 Westy, P22 interior, FI 2.0 l Federal, GE engine (hydraulic lifters)
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raygreenwood
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Joined: November 24, 2008
Posts: 21512
Location: Oklahoma City
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| Posted: Fri Dec 15, 2017 8:18 am Post subject: Re: Ignition wiring refresh |
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| furgo wrote: |
Very good point. Also a non-symmetrical (front vs. back spark plugs) resistance setup, then.
In our busses, assuming copper cables, I can think of these possible total resistance values for a single wire:
• Integral resistor on rotor and connector (non-resistor spark plug): 6.0 kΩ to 6.4 kΩ
• Integral resistor on spark plug only (resistor spark plug, rotor and connectors replaced with 0-Ω ones): 5 kΩ
• And for those who didn't replace the rotor and connectors when using spark plugs with resistor: 11.0 kΩ to 11.4 kΩ
So at the end of the day, the 0.4 kΩ most probably haven't got a noticeable effect. The difference in values simply surprised me initially, as I thought they were all the same (and in fact they were in my bus, but perhaps not originally so).
Finally, there's an interesting section on http://www.ratwell.com/technical/IgnitionSystem.html with measurements and spark plug voltage waveform variation during the firing event on a 0 Ω vs. 1 kΩ vs 5 kΩ rotor (scroll down to the "Which rotor" header, sorry, no direct link). |
In our qpplications....BECAUSE they are solid wire core.....the length of wire should have no measureable effect on resistance. If you have the resistor unscrewed from the end of the wire and see a significant difference in resistance between two wires.....one is defective.
As noted the 0.4 ohm difference will not matter. However...running without a resistance choke point at both rotor and wires....does make a difference.
Not a difference you will feel at least not in a bus (not with our low output systems)....but in wear to rotor tip and cap contacts.
Without the resistance in rotor it strings out the arc between rotor and cap contact and tends to carbonize the trailing edge of both rotor and cap contact. Same effect at the plug not using a non-resistor wire with non-resistor plugs.....but with only an 18kv coil (about 12kv at the plug).....its just not a worry.
If you tend to use non-resistor wire....just use a resistor plug. Ray |
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