[Diy_efi] OT - platinum plugs burning up wires

clair.davis at charter.net clair.davis
Tue Sep 13 02:23:13 UTC 2005


In any healthy engine I have, I run Bosch plats exclusively.  I've never had
a problem with one, knock wood.  Currently, I've got them in my Daytona
turbo, gapped at 0.025", which it DID like better than gapped at 0.050"
under boost. I also have them in my old carb + low-compression + big cam
440, gapped at 0.050".  Both seem to run just fine, in spite of their
radically different setups.  I wish my 340 had higher compression so I'd
have some input on the compression effects, but it's sadly low compression,
too.  I'll be changing to platinum plugs in it now that it's thoroughly
broken in and appears to be in good health, too.

Clair
69 Valiant 340+7730 experiment
FTWTX


----- Original Message ----- 
From: "Rick McLeod" <dunvegan at sbcglobal.net>
To: <diy_efi at diy-efi.org>
Sent: Monday, September 12, 2005 8:55 AM
Subject: Re: [Diy_efi] OT - platinum plugs burning up wires


> I have to agree on the turbo w/ plat's, I have 4
> gas/turbo cars, and ALL of them (3 Volvos and a GM)
> HATE plat's, stock OEM plugs w/ large electrodes seem
> to create the best light-off of the mix under higher
> boosts, which relates to higher compression. I don't
> have a 'hi-comp' engine to relate to (my GM v8's are <
> 9:1) and plat's weren't around when I built my 10.5:1
> GM BB nearly 30 years ago, so no experience there, but
> would be interested to hear what folks running hi-comp
> have learned.
>
> Thanks, everyone, for the great disscussions so far.
> And, what's even better, no flames! Thanks
>
> --- David Allen <davida1 at hiwaay.net> wrote:
>
> >   Didn't hurt my 1991 TBI 305 with stock ign.
> > components.  Hasn't hurt my
> > mother's 1989 LeSabre with Series I 3800 and DIS
> > ignition. On all these cars
> > the ignition leads last fine.  Had one coil failure
> > that I couldn't explain
> > on the 305 but I was using a coil of unknown origin.
> >   Modern graphite core wires can be fickle.  The
> > core may be brittle; or the
> > wires may be stressed or pulled during the service.
> > A crack opens in the
> > core and as the ignition fires across this crack it
> > burns away more and more
> > of the core. Finally the wire is open-circuit.
> >   However my turbo engine does not run as well with
> > Bosch Platinums as it
> > does with standard plugs.
> >   Maybe I am just lucky with not ruining ignition
> > leads?
> > David
> >
> >
> > ----- Original Message ----- 
> > From: Bret Levandowski
> > To: diy_efi at diy-efi.org
> > Sent: Saturday, September 10, 2005 5:26 PM
> > Subject: Re: [Diy_efi] OT - platinum plugs burning
> > up wires
> >
> >
> > Platinum plugs have a higher core resistance and
> > require more current and
> > more precise control to fire. This is not true of
> > all platinum plugs but
> > most. If the resistance in the plug or across the
> > gap is too much, the
> > current can't 'escape' through it's normal path and
> > it has to go somewhere.
> > Always the point of least resistance, whether it is
> > the cap/rotor or plug
> > wires it is going to flow somewhere. Either way, it
> > is going to burn
> > something up; possibly even your coil.
> > I have experimented with different plugs and
> > different systems and have seen
> > all types of failures. From what we saw, AC Delco
> > platinum plugs will burn
> > up coils and wires quite nicely on older motors.
> > SureFire triple platinums
> > work well in just about any type of performance
> > motor (high comp/high energy
> > ignition), but not so well in older or lower
> > compression motors. It wasn't a
> > 'scientific experiment', just what we saw happen by
> > changing plugs. So after
> > much rambling..... Yes, what the tech said is true.
> > You can burn up ignition
> > components using platinum plugs in non-platinum
> > applications. I have done it
> > myself and had to have someone else tell me why.
> > Unfortunately, you don't
> > know 'til you try.
> >
> > Rick McLeod <dunvegan at sbcglobal.net> wrote:
> > Sorry for being off topic, but I know there is a lot
> > of knowledge in this area on this list, and this
> > might
> > be of interest to discuss (remember the recent plug
> > discussion?)
> >
> > Recently I had an issue w/ a Hyundai where the plugs
> > were replaced w/ platinum at a tune up. A few
> > k-miles
> > down the road, the car began running poorly, and was
> > taken to the dealer where it was diagnosed as having
> > 'burned up ignition wires'. The service advisor
> > stated
> > that you MUST NOT use platinum plugs in these cars
> > since it will cause this to happen.
> >
> > My question is: What is different about them that
> > would cause this, it sounds like 'bunk' to me, but
> > am
> > looking to the vast world of knowledge on this list
> > to
> > get some insight.
> >
> > Thanks
> >
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