I vote for standard Bosch Platinums. Used in all my cars. Never had a problem,
and
they seem to last forever.
Al J.
Bob Palmer wrote:
> Guys,
>
> Some of you may recall that a few months back I had some problems with
> spark plugs that spawned several related topics and questions. I had had a
> set of Autolite AP45 platinum plugs in my Tiger's engine for quite some
> time, perhaps 15-20k miles or so. Noticing that it was idling rough, I
> pulled these old plugs and found that two - #1 & #8 were missing most of
> the center electrodes. I got lots of advice relative to spark plugs, most
> of which pointed to NGKs as the best. On the other hand, Autolite seems to
> have slipped their quality since they were bought out and the manufacturing
> transferred to Mexico. However, on advice attributed to Dan Walters, I
> bought and installed a set of Autolite AP124 plugs, which I believe are for
> a truck application and presumably run pretty cool - which is a good thing
> for race use too, which is the application Dan was probably recommending
> them for. The AP124s seemed to work well, although I noticed they didn't
> protrude as far into the combustion chamber as the AP45's and other plugs
> I've used. I expected this to have some possible consequences at idle and
> low rpm, but it wasn't noticeable at first. Over the past few weeks though,
> I have noticed more and more hesitation pulling away from a stop until the
> rpms get going a little. Monday, I made a trip from Vista to Santa Barbara
> and back. The engine ran great on the highway, but yesterday when I drove
> it, it was idling extremely rough. Actually, it idled fine until it got
> hot, then rough. Aha it though, too rich. Leaned it out, but that made it
> worse. Played with spark advance, more helped, but when it idled best the
> advance was so much that would fight the starter and would scarcely start.
> I got home OK, but was thankful for a minimum of stop-and-go traffic.
>
> Today I pulled the plugs. Some looked very clean, some looked so-so, and
> two looked pretty carboned up. Back to Pep Boys to get a new set of plugs.
> But which kind this time? At least the AP124s had lasted a long time. I
> tried to get some NGKs, but they didn't have them in stock. OK, what about
> Bosch? These they had, either the regular platinum (4226 aka DR 8 BPX) at
> about $2 each, or some new fancy platinum quad-gap plugs for $5 each. I
> bought the $2 plugs.
>
> BTW, all of these plugs are resistor types with about 6k ohms resistance.
> Also, I'm running an MSD and have spiral wound spark plug wires.
>
> After removing all the old plugs, and before installing the new ones, I ran
> a compression check just to be sure. Yep, 190-200 lbs/in on each cylinder
> (cold). I had previously indexed the AP124 plugs and had the cylinders
> marked on my indexing tool. Right away I find out the Bosch plugs index
> about 45 degrees offset from the Autolite plugs. Did anyone tell me this
> before?? Oh well, after considerable trial and error I get eight in
> pointing pretty much the right direction. Well, the new plugs did the
> trick. The engine idles smooth again and pulls from a stop without
> hesitating, sputtering, missing, etc. How long these will last I'm not
> sure, but I hope they last longer than the AP124s did. The AP124s may be
> just the ticket at the track, but for street use, they seem to be a bad
>choice.
>
> Well, just thought I'd pass on a little more of my experience spark plugs
> in case any of you are having similar experiences.
>
> Well, TTFN guys,
>
> Bob
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