[Healeys] Plugs

Sun Mar 19 10:15:02 MDT 2023

Now that I've had my first cup of coffee and am somewhat sentient I 
recalled that Pertronix advises /against/ using stranded metal wire 
secondaries with its Ignitor units. This made no sense to me because the 
coil effectively electronically isolates the primary circuit the Ignitor 
controls from the secondary, high voltage circuit (coils are sometimes 
used in electrical circuits for this property). But, someone pointed out 
the EMI from metal wires could adversely affect the Ignitor as it 
employs a Hall Effect sensor to detect the rotation of the distributor 
shaft (6-cyl Ignitors have a collar with 6 magnets, the 4-cyl units can 
apparently detect the lobes from their shape and don't require the 
collar, and there's likely little to no room for one anyway*). IOW, a 
strong magnetic field could affect an Ignitor's ability to sense the 
magnets or cam lobes. If the Pertronix people--who I've found to be very 
knowledgeable and helpful--encountered this just a few times they would 
likely issue a broad advisory against it (I suspect 95% plus of their 
business is with the hot rod crowd, who likely use suppressor wires 
because they're prettier). So, if you use a Pertronix Ignitor, use 
non-resistor plugs and have sporadic misfires you could try using 
resistor plugs. Offhand, I think most of the plug caps offered by 
suppliers have resistors.

* When I first opened the box for my BN2's Ignitor I thought 'Crap, they 
forget to send the magnet collar.' Then, I broke down and read the 
instructions.

On 3/19/2023 6:52 AM, Michael Oritt wrote:
> "I always thought the resistor plugs were to introduced to suppress 
> interference with car radios, which I don’t have,"
> -----------------------------------------------------
> They also eliminate your ignition's noise in nearby vehicles.
>
> Best--Michael Oritt
>
>
> On Sun, Mar 19, 2023 at 8:11 AM m.g.sharp--- via Healeys 
> <healeys at autox.team.net> wrote:
>
>     I do exactly what Bob does with my BT7 except I use a non-resistor
>     plug – Champion N12YC and 0.028” gap.  I too use a Lucas Sports
>     coil.  I always thought the resistor plugs were to introduced to
>     supress interference with car radios, which I don’t have, but I am
>     happy to be corrected on that.   I think plugs are unnecessarily
>     changed too frequently. I remove them once in a while (every few
>     years) and clean and check the gaps.  I run them until they shows
>     signs of deterioration.  I have never had a plug fail me in the
>     Healey.
>
>     Mirek
>
>     *From:*Healeys <healeys-bounces at autox.team.net> *On Behalf Of *Bob
>     Spidell
>     *Sent:* March 18, 2023 2:17 PM
>     *To:* healeys at autox.team.net
>     *Subject:* Re: [Healeys] Plugs
>
>     I've run over 150K miles on Champion plugs with nary an issue (and
>     will continue to do so); RN12YC for the BJ8 and whatever the
>     recommended is for a 100M (RN10C?). With Pertronix Ignitors in
>     both, I run slightly over 'book' value (0.025") at 0.028" and both
>     run very well (I also run stranded copper wire secondaries, so the
>     'R' is important, plus the plug caps have a resistor in them as
>     well). My one-time auto shop teacher father maintained whatever
>     spark was sufficient to ignite the mixture was adequate--mixture
>     and compression took it from there--but a larger gap induces a
>     'hotter' spark which may be beneficial with leaner mixtures and at
>     higher engine RPM (but has less margin as the electrode erodes). A
>     larger gap requires the coil to produce more secondary voltage to
>     jump the gap; a sports coil may be required to produce a
>     consistent spark. 12K miles on plugs is fine in my experience--as
>     long as the engine is in good nick--and they can be cleaned and
>     re-gapped at least once. Sandblasting is a no-no as it will pit
>     the ceramic insulator and can cause issues.
>
>     I came across a YouTube video by David Vizard where he claims E3
>     Diamond 'Split Fire' plugs produced slightly better mileage; yep,
>     E3 makes a plug for Big Healeys (6-cyl only, I think). I've heard
>     rumors that counterfeit NGK plugs are in the market.
>
>
>     On 3/18/2023 9:49 AM, Simon Lachlan via Healeys wrote:
>
>         Here’s a can of worms that we haven’t delved into for a while….
>
>         So, I’m trying to get all my ducks in a row for a short run
>         abroad. Car is a MkII BT7 with a DW fast road cam, 3 HD6s, big
>         bore 6 branch and 123Ignition plus a so-called Sports Coil.
>
>          1. I was looking through my library of files on Healey topics
>             and saw that we were all over the place on plug gaps…..all
>             the way up to 0.035”. So what’s the opinion there??
>          2. And which plug? Seemed to be mostly between NGK’s BP6ES &
>             BP5ES. Was a hold-out for their B8EGV 5627  but thatwas
>             dismissed fairly vigorously by Jeremy Welch as being way
>             OTT for normal road use.
>          3. And, I have 12,000 miles+++ as plug replacement mileage so
>             long as they still look and perform OK. Any thoughts?
>
>         Thanks, Simon
>
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