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MG TD TF 1500 - Spark Plug Wires

Looking to revert back to the original style black spark plug wires and connectors. Do I need 7mmm or 8mm wire? No radio installed, so just looking for the best source of wires. Running a Petronix ignition and a modern Lucas Sports coil.
L Karpman

7 mm. Maybe Rhode Island Wiring would be a good place to start. Let them know you're running an EI. There's some good stuff on this in the archive. Cheers
Peter TD 5801
P Hehir

Thanks Peter, but I find the info in the archives conflicting, especially when it comes to the older and newer Petronix ignitions. Some say special wire is needed for an EI and others running older EI feel standard wire is just fine, unless I am misreading. What I want to end up with is black, rubber covered copper stranded 7mm wire, which I will use all the standard TD connectors for the distributor and plugs.
L Karpman

G'day LK. I have a Dutch EI 123 & the makers recommended that I NOT use copper wire. I went with black 7mm Magnacore's Electrosports 70 – Ignition Cable – SS25 – Metallic Inductance EMI Suppressed Conductor – All Silicone Construction. The use of suppressed cable is recommended with an Electronic Ignition such as the EI 123.

If you’re able to find a set of near original Champion HTC 2 Bakelite spark plug caps they CAN be modified for use with a modern 7mm suppressed ignition cable, in spite of assertions to the contrary! All that is required is a drill press, an offcut of say 18mm ply, a set of drill bits & a steady nerve. The Champion HTC 2‘s, which are almost identical to the original Bakelite caps, are constructed with a screw that the HT lead screws into. When using the Magnacore cable it is necessary to remove this screw. Failure to do so will mean the cable will only last a very short time.

I first tried a screwdriver which proved useless as it was difficult to both hold the cap & apply enough force to get the head of the screw to move. Obviously too much pressure on the Bakelite would break it. One of the four screws was loose & this proved the most difficult to remove. I then discovered it was molded into the cap during manufacture. By drilling a 7/16” hole in the ply offcut secured in the drill press vise, inserting the cable end of the cap into the ply & then carefully using a series of 7 very sharp bits from 7/32” to 5/16”, I was able to remove the screw, the metal spark plug sleeve & some of the Bakelite. As a surprising amount of heat was generated I used cold water to cool things down. This has the added bonus of swelling the ply & making the cap more secure as the lead end has a slight taper. The key is sharp drill bits & plenty of patience as the wall thickness has to be reduced to ensure a snug internal fit of the cable connector. Remove too much & the cap will be loose on the lead & the wall thickness will be compromised. The swollen ply also helps keeps the wall intact. I found finishing @ 5/16” & constantly checking to ensure a concentric hole, ensured a pleasing result.

By using some thinners the manufacturer’s branding can be removed. I purchased the essential brass fittings from the cable supplier for both the distributor, coil & the plug ends, all of which crimp over & into the cable. This means the original look of the leads & fittings is maintained. As my crimping tool wasn’t designed to secure this type of fitting, I cut the leads to the correct length, allowing a little extra for the core to be folded back under the fittings & took them to be crimped at the local auto electrician. Ensure that the red fibre cable manager is fitted first! DAMHIK. I posted some pics on my thread "Original Bakelite Plug Caps & Suppressed Ignition Leads" in the archive. You'll note I have corrected a couple of errors from that text in the para's above.

You end up with suppressed black 7mm HT leads, almost original black Bakelite Champion HTC 2 plug connections & original distributor & coil lead fittings. I also used suppressed plugs. Unnecessary I know but that's just me as I don't want stray EMF's messing with my EI. Cheers
Peter TD 5801
P Hehir

Larry, unless you have one of the new lobe-sensing pertronix units, i.e., LU-146LS, you can use solid core wires. Plain old auto parts store 7 mm stranded wire core black wires are fine. Personally, I like the fit of 8mm wire. Bud
Bud Krueger

Thanks Peter and Bud.

Bud, I have the older Petronix and have been running 8mm bumble bee wire and Champion plug connectors for years with no issues. I simply want to eliminate the Champion connectors (don't like the screw in ends as they loosen over time). The reason for the 7mm wire is that the 8mm wire is too thick to fit the holes in the wire separator without enlarging the holes, which weakens it IMHO.

Note: Why is it called solid core wire, if the wire is stranded (as needed to be splayed out to properly fit the distributor screw connector washer)? Sounds like a misnomer to me.
L Karpman

Just put a Moss ignition wiring set on ebay. Auction number: MG TC TD TF MOSS IGNITION WIRING SET (251757151675)if you are interested.

F Filangeri

Thanks Frank. I have all the components except the new wire. Good luck with your auction. Larry
L Karpman

It's an odd naming thing. In this case 'solid' means the wire(s). The option is the resistive material. I know what you mean about the spreader. It can be a pain. Bud
Bud Krueger

This thread was discussed between 14/12/2014 and 15/12/2014

MG TD TF 1500 index

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