HT Ignition Leads

The place to "speak geek"
Post Reply
User avatar
scott.a
Posts: 138
Joined: Mon Sep 05, 2016 1:50 pm

HT Ignition Leads

Post by scott.a » Fri Feb 28, 2020 11:08 am

Went to change the rotor cap yesterday and two of the ends of the HT leads snapped off - without much effort i must say.

They are currently magnecor leads that are fitted and for a like for like replacement are £83. The other option is OEM ones for £40.

Is it worth sticking with the magnecor leads and paying the premium? It feels like downgrading would be wrong.

Thoughts?

User avatar
robin
Jedi Master
Posts: 10525
Joined: Mon Mar 27, 2006 1:39 pm

Re: HT Ignition Leads

Post by robin » Sat Feb 29, 2020 12:08 pm

What makes the magnecor ones better? I would fit OEM. Replace everything (rotor arm, cap, leads). On S1 the "rain cover" over the spark plugs is not very good fit and you get water into the spark plug bores, so that end is probably a corrosion fest too - I would be checking all the plug tops too.

Make sure when routing the cables that, as far as possible, they sit nicely in the wee rubber spacers/cable guides and that they aren't chafing. This will increase the longevity of the cables, though they will still fail eventually anyway.

Cheers
Robin
I is in your loomz nibblin ur wirez
#bemoretut

User avatar
scott.a
Posts: 138
Joined: Mon Sep 05, 2016 1:50 pm

Re: HT Ignition Leads

Post by scott.a » Tue Mar 03, 2020 11:43 am

robin wrote:
Sat Feb 29, 2020 12:08 pm
What makes the magnecor ones better? I would fit OEM. Replace everything (rotor arm, cap, leads). On S1 the "rain cover" over the spark plugs is not very good fit and you get water into the spark plug bores, so that end is probably a corrosion fest too - I would be checking all the plug tops too.

Make sure when routing the cables that, as far as possible, they sit nicely in the wee rubber spacers/cable guides and that they aren't chafing. This will increase the longevity of the cables, though they will still fail eventually anyway.

Cheers
Robin
THe Magencor ones are solid copper where as some oem ones are built from carbon covered string. Ive got a new rotor cap and - once i get the correct one - an arm to go. I did the plugs last year and one of them was rotten with corrosion. Its kept indoors mostly now and rarely left in the rain. will check the condition of the plugs as well when im doing the job.

I ordered the Magnecor set and they have literally just arrived.

User avatar
robin
Jedi Master
Posts: 10525
Joined: Mon Mar 27, 2006 1:39 pm

Re: HT Ignition Leads

Post by robin » Thu Mar 05, 2020 8:34 pm

The graphite core will conduct perfectly well ... remember the spark jumps across an air gap (huge resistor) so the resistance of the lead isn't all that important. Also the OEM cables might be deliberately resistive to suppress RF (a slight resistance in the cable limits the rate of change of current - so called dI/dt - which in turn reduces the harmonics transmitted).

But I doubt it will do any harm to use copper cables.
I is in your loomz nibblin ur wirez
#bemoretut

User avatar
graeme
Posts: 3528
Joined: Tue Mar 15, 2005 11:29 am
Location: Kintore

Re: HT Ignition Leads

Post by graeme » Fri Mar 06, 2020 11:47 am

I always fitted Magnocor HT leads on my S1s, because, through my own extensive testing in both laboratory and real-world conditions, I found the Magnecor leads to be red, while the OEM ones were black.
211
958

fd
Posts: 883
Joined: Mon Apr 23, 2007 4:56 pm

Re: HT Ignition Leads

Post by fd » Fri Mar 06, 2020 3:05 pm

Series resistance (in the lead or in the plug itself) dramatically reduces RF noise (as robin said) but also helps manage wear on the plug electrode.

Neither may matter, but both could cause problems . . .

User avatar
BiggestNizzy
Posts: 8932
Joined: Sun May 27, 2007 6:47 pm
Location: Kilmarnock
Contact:

Re: HT Ignition Leads

Post by BiggestNizzy » Sat Mar 14, 2020 12:41 pm

What I like about the magnacor leads on an S1 is the little rubber skirt around the top of the plug bore it helps stop the plug bores filling up with water.

That and red looks cooler :D
Sent from my ZX SPECTRUM +2A

Post Reply