993 Beru Silicone Copper "replacement" Ignition Leads
10-16-2011, 10:02 AM
#1
Rennlist Member
Thread Starter
993 Beru Silicone Copper "replacement" Ignition Leads
After 15 years, the original ignition leads on my 1995 993 were starting to show signs of age, physically.
Electrically, they were fine, but the ignition leads had hairline cracks in the insulation where they make tight bends at the valve covers. The heat from the adjacent mufflers accelerates this aging process; the leads within the engine compartment were fine.
At about $500 for a new Beru ignition lead set
, I decided to just replace the actual leads and reuse the Beru caps at the distributor caps and spark plugs. Besides, after cleaning up the caps and testing them, they looked like the day they were manufactured.
This DIY is about making up your own set of Beru Silicone Copper Ignition Leads or if you just intend to buy a set of "replacement" ignition leads, where to place the cable holders along the lead lengths. TIP: while doing any work, taking digital pics during any DIY might be of help during the reassembly process.
My new Beru Silicone Copper Ignition Leads and original spark plugs caps...
Unfortunately, even after all these years, no one had taken the time to post lead lengths or the locations of the ignition lead hold-downs. Charts and diagrams are further down this thread.
Making your own set of ignition leads vs buying "replacement" leads:
I weighed the costs of making my own set of ignition leads against buying a complete ready-made Beru ignition lead set. Despite the high cost of the Beru crimping tool, I decided on the DIY option. I could have just bought a set of "replacement" ignition leads that are already being sold on a Porsche parts site, but I had doubts as to their quality since they are not made by Beru.
I discussed my intent to make my own set on a thread that someone started on DIY replacement Beru ignition leads. One individual on that forum did everything in his power to discourage me from making my own ignition wires; how I would be wasting lengths of wires trying to perfect my crimping technique and the hours I'll spend determining each wire length which would be difficult because they don't lie flat. Well all that data is right here for others to use; that individual never posted such data or information. A really useful individual on a forum
.
The crimp shown below is my first crimp and its perfect and identical to the Beru crimps found on the original Porsche/Beru ignition wires I replaced.
A length of Beru 7 mm Silicone Copper Cable with a Beru M3 Terminal installed...
I performed a pull test to verify the integrity of my crimps using the Beru crimper. What failed was the stranded copper wire which "tore" at 58 pounds; the stranded wire had not pulled out of the M3 terminal.
Preparing the cable for a Beru M3 Terminal:
What is important is cutting the insulation square to the cable and not nicking any of the wire strands. The latter will/might cause failure of that strand in time; not the end of the world, but we do expect excellence...in a Porsche.
I made my own jig to do so. Using a tool such as a wire stripper would not provide those results.
With the cable insulation trimmed squarely, it ensures that the cable casing fully sits within the barrel of the M3 terminal. The advantage to cutting the insulation square is that it makes full contact with the end of the M3 terminal when it is slipped on. This provides a bit of extra friction against rotation of the M3 terminal on the cable. Although the crimp does that extremely well, why not take it that extra step.
The next step involves cutting the stranded wire to the correct length; 6.8 mm according to the indication on the Beru crimper.
Start off with a slightly longer section of stranded wire and cut it down a few thou at a time (you need good cutters to do this; your local hardware store will not carry those). If the stranded wire is too long, the M3 terminal will bottom out and spin on the end of the stranded wire and therefore, the end of the insulation will not make contact with the end of the M3 terminal. You want full contact of the insulation with the M3 terminal while also having the full length of the stranded wired within the M3 terminal for crimping purposes. When this condition has been met, you can crimp the M3 terminal; first the end to crimp the stranded wire and then the barrel.
Ignition Lead Length Data & Cap Resistance Specifications:
My "measured" cap resistances were included for information only. Yours will vary slightly.
Beru Ignition Cable Holder Locations:
Ignition lead placement and routing at the dual distributor caps:
Some will argue that the resistors within the caps will fail and that one should replace the whole ignition lead set. Sure they can fail like anything else can fail, even a resistor in the cap of a new ignition lead set. All my caps met the specified values and looked like new after 15 years.
Further information and pics are on my Beru Ignition Cables write-up.
PM me if you have specific questions.
Electrically, they were fine, but the ignition leads had hairline cracks in the insulation where they make tight bends at the valve covers. The heat from the adjacent mufflers accelerates this aging process; the leads within the engine compartment were fine.
At about $500 for a new Beru ignition lead set
, I decided to just replace the actual leads and reuse the Beru caps at the distributor caps and spark plugs. Besides, after cleaning up the caps and testing them, they looked like the day they were manufactured.This DIY is about making up your own set of Beru Silicone Copper Ignition Leads or if you just intend to buy a set of "replacement" ignition leads, where to place the cable holders along the lead lengths. TIP: while doing any work, taking digital pics during any DIY might be of help during the reassembly process.
My new Beru Silicone Copper Ignition Leads and original spark plugs caps...
Unfortunately, even after all these years, no one had taken the time to post lead lengths or the locations of the ignition lead hold-downs. Charts and diagrams are further down this thread.
Making your own set of ignition leads vs buying "replacement" leads:
I weighed the costs of making my own set of ignition leads against buying a complete ready-made Beru ignition lead set. Despite the high cost of the Beru crimping tool, I decided on the DIY option. I could have just bought a set of "replacement" ignition leads that are already being sold on a Porsche parts site, but I had doubts as to their quality since they are not made by Beru.
I discussed my intent to make my own set on a thread that someone started on DIY replacement Beru ignition leads. One individual on that forum did everything in his power to discourage me from making my own ignition wires; how I would be wasting lengths of wires trying to perfect my crimping technique and the hours I'll spend determining each wire length which would be difficult because they don't lie flat. Well all that data is right here for others to use; that individual never posted such data or information. A really useful individual on a forum
.The crimp shown below is my first crimp and its perfect and identical to the Beru crimps found on the original Porsche/Beru ignition wires I replaced.
A length of Beru 7 mm Silicone Copper Cable with a Beru M3 Terminal installed...
I performed a pull test to verify the integrity of my crimps using the Beru crimper. What failed was the stranded copper wire which "tore" at 58 pounds; the stranded wire had not pulled out of the M3 terminal.
Preparing the cable for a Beru M3 Terminal:
What is important is cutting the insulation square to the cable and not nicking any of the wire strands. The latter will/might cause failure of that strand in time; not the end of the world, but we do expect excellence...in a Porsche.
I made my own jig to do so. Using a tool such as a wire stripper would not provide those results.
With the cable insulation trimmed squarely, it ensures that the cable casing fully sits within the barrel of the M3 terminal. The advantage to cutting the insulation square is that it makes full contact with the end of the M3 terminal when it is slipped on. This provides a bit of extra friction against rotation of the M3 terminal on the cable. Although the crimp does that extremely well, why not take it that extra step.
The next step involves cutting the stranded wire to the correct length; 6.8 mm according to the indication on the Beru crimper.
Start off with a slightly longer section of stranded wire and cut it down a few thou at a time (you need good cutters to do this; your local hardware store will not carry those). If the stranded wire is too long, the M3 terminal will bottom out and spin on the end of the stranded wire and therefore, the end of the insulation will not make contact with the end of the M3 terminal. You want full contact of the insulation with the M3 terminal while also having the full length of the stranded wired within the M3 terminal for crimping purposes. When this condition has been met, you can crimp the M3 terminal; first the end to crimp the stranded wire and then the barrel.
Ignition Lead Length Data & Cap Resistance Specifications:
My "measured" cap resistances were included for information only. Yours will vary slightly.
Beru Ignition Cable Holder Locations:
Ignition lead placement and routing at the dual distributor caps:
Some will argue that the resistors within the caps will fail and that one should replace the whole ignition lead set. Sure they can fail like anything else can fail, even a resistor in the cap of a new ignition lead set. All my caps met the specified values and looked like new after 15 years.
Further information and pics are on my Beru Ignition Cables write-up.
PM me if you have specific questions.
03-13-2012, 11:56 AM
#2
Addict
Rennlist Member
Rennlist Member
PelicanParts now sells these DIY Ignition wire replacement kits, in Beru Black or Red, with instructions and legend to which wire length goes where. Not bad for $175-ish. Good work Alex!
Mark
Mark
03-13-2012, 12:18 PM
#3
Rennlist Member
Thread Starter
If I'm getting comments in PMs, its for the quality work and very detailed instructions, some of which is already posted in this thread. Pelican Parts should be able to sell them for far less considering my costs are far higher and at $175, I include shipping. Taking my time into account, I guess I'm making them for the fun of it.
03-14-2012, 12:09 PM
#4
Good work indeed. I just ordered a crimp tool, terminals and wire too as I have a few to replace here in Holland. However checking the cable lenghts I do not understand the tables for lenght. For example in your Ignition Lead Length Data & Cap Resistance Specifications table for: II-1 #1 bottom, cable lenght is 775mm. But in the Beru Ignition Cable Holder Locations for same cable is 418+110+112+205=845mm is 70mm longer. How this to be read?
03-14-2012, 12:51 PM
#5
Rennlist Member
Thread Starter
Good work indeed. I just ordered a crimp tool, terminals and wire too as I have a few to replace here in Holland. However checking the cable lenghts I do not understand the tables for lenght. For example in your Ignition Lead Length Data & Cap Resistance Specifications table for: II-1 #1 bottom, cable lenght is 775mm. But in the Beru Ignition Cable Holder Locations for same cable is 418+110+112+205=845mm is 70mm longer. How this to be read?
418 + 112 + 205 + 40 (the width of 2 cable holders) = 775 mm...spot on.
Trust someone with Austrian blood to be accurate.
10-22-2012, 10:53 PM
#7
Cruisin'
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Its true that parts of your vehicle would soon wear out. Just a few weeks ago I had my spark plugs replaced by a near auto repair shop because I am not much into technical stuffs. I am more indulged into the exterior and interior design of my ride. I did purchase online cause it is a lot cheaper(visit partstrain here). For the tools, the shop had almost every tool needed for the replacement. Crimping tool. The length could be a little tricky since the fittings is at stake.
