Re: Magnecore wires

[Scott Fisher <sefisher@domain.elided>]

Robert Murphy has some questions about Magnecore wires in digest V7
#1058.

>I am contemplating on installing the Magnecore KV85 sparkplug 
> wires on my 90 Spider and would like to hear for those who 
> have used them.  

I haven't used the Magnecore brand, but I've replaced the plug wires on
many different cars over the years, including my '67 Alfa which is
running the Marelliplex electronic ignition.

> The reason I am thinking about doing this is because my spider
> is about to reach 50k miles and is ten years old.  Most things
> age and I suspect ignition wires do to.

They do.  You can quickly check the condition of plug wires in a dark
garage or at night by letting the engine idle, then lifting the hood. 
Look for a bluish corona around the wires; if you see any, the wires
have deteriorated internally and are not delivering full voltage to the
spark plugs.  (And if you're checking in a dark garage, don't check too
long with the door closed and the engine running...)

> I am going to replace the dist. cap and rotor and the spark plugs 
> as well, among other things.  

You'll get much more obvious results by doing that than by replacing the
plug wires, but it's good to replace all the parts.

By the way, here's the least confusing way to make sure you get all the
wires lined up correctly if you're replacing the wires and the cap at
the same time:

1.  Pull the old cap but keep the wires connected to it.

2.  Snap the new cap (and rotor) into position on the distributor.

3.  While holding the old cap in the same orientation as the new cap,
pull one old plug wire from the cap and note the empty slot on the old
cap.

4.  Trace the wire unplugged in step 3 to its spark plug and remove it
from the engine.  

5.  Match the wire removed in step 4 with a wire of approximately the
same length in the new set.

6.  Install the new plug wire identified in step 4 by connecting it to
the empty spot on the new distributor cap and the empty spark plug.

7.  Repeat steps 3 through 7 for the remaining plug wires.

I have spent all the time that I plan to in this life going "Now let's
see... which wire went to the #3 plug?  I think it went to this post on
the distributor cap... or was it that one?  Now, does the rotor go
counterclockwise or clockwise on this car?  Lemme see that book
again..."  

Another tip: mark your plug wires so that if you ever have them all off
the car (say, when you have to remove the cam cover to check the valve
clearances), you'll know where they go back.  I've seen three different
techniques for marking plug wires:

1 - the cheater's way: you can buy strips of tape with numbers in them,
and just tape "1" "2" "3" and "4" on the wires.  

2 - the calligrapher's way: use a Sharpie to write 1, 2, 3 and 4 on the
insulation of the plug wires.  Use a nice cancellaresca corsiva (with a
chisel-pointed sharpie) for best results.  Works only on bright colored
plug wires.

3 - the clean way: wrap one tie wrap (in a contrasting color) around the
#1 plug wire.  Wrap two tie wraps around #2.  Wrap three tie wraps
around #3.  Leave #4 blank.  For added neatness points, align all tie
wraps so that the first ones on each wire are the same distance from the
spark plug connector.

> Should I expect any improvements from these wires over the old 
> stock wires?

That depends on how much your stock wires had deteriorated.  If you're
still running the stock components in the rest of your ignition system,
putting in high-performance plug wires isn't going to make a measurable
improvement unless there was something wrong with the old bits.

> Are they just a waste of $?

In the long run, probably not.  Plug wires aren't something you normally
change as often as plugs (at least not on our cars; maybe on a car with
100k mile plug change intervals), or as the distributor cap & rotor, but
ten years is probably a good time to replace them.  

It's a good, sensible idea to replace things before they fail -- timing
belts are a good example, where it seems wasteful to throw away a belt
that's working perfectly well just because it has 60,000 miles on it. 
But considering the risk of engine damage if a timing belt fails, it's
very sensible to replace it.  Plug wires aren't going to cause quite as
much damage if they go out as a timing belt, but why wait till one wears
through or the core breaks or the insulation chafes off and grounds to
the cam cover?

> Do the OEM wires usually last longer than one normally expects?

I don't know... I'm not sure how long to expect wires to last.  Anyone
know the recommended replacement interval?  I don't think it's in the
owner's manual; there are times given for changing belts, filters, and
the like, but not for changing plug wires.

> I know ignition wires dont normally fail, but they do deteriorate, 
> right? 

Right.  More than once, I've noticed smoother idle and smoother (if not
necessarily better) acceleration after installing new plug wires, which
led me to believe that the ones I took out had deteriorated.  In
particular, wires with chafed or cracked insulation can make a car
difficult to start when cold because condensation collects inside the
insulation and affects their ability to deliver electricity to the plug.

> Replacement OEM wires cost more than the Magnecore.  So does that
> mean the OEM wires are technically better?

Not necessarily.  I don't know the Magnecore specs, nor the OEM specs
for that matter.  (I used to use the Lucas "bumblebee" wire because it
looks right under the hood of a vintage British sports car; I haven't
replaced the wires on the Spider yet because they appear to be no more
than a couple of years old, and when I replaced the wires in the Junior
I used some yellow Accel stock that I happened to have lying around the
garage.)  But sometimes the extra cost for OEM items is justified, and
sometimes it isn't.  I don't know which is the case here.

> Thanks again for all your help and advice.

You're welcome!  Hope this provides some useful information, especially
if the replacement procedure can help keep someone else from having to
have the car towed to a shop to find out the distributor had been put in
180 degrees out of phase, which is why the car would barely stagger down
the alley, and then only after replacing the plug wires *backwards* from
the order shown in the manual.  I wore down the battery trying to start
the car.  What can I say, that was 15 years ago...

Best,

- --Scott

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