Alrighty then! Since my MGA is driven a lot it makes a good vehicle for long term testing. Occasionally I can shed a little light on the reality of reliability and cost vs. value, so here is another one of those nifty long term test reports.

I have used lots of different types and brands of spark plugs in my MGA over the years, and they all work pretty much the same for function, performance, fuel economy, etc. So for many years I was using whatever was cheap and conveniently available, which was usually Autolite 63 non-resistor type from the local NAPA store for about dollar each. A high compression race engine might need a little different heat range, but they're still cheap. Being cheap and easy to change in the MGA it's hard to beat the price/value.

I would avoid Champion resistor plugs like the plague. It has been my experience that about 10% of them may be bad right out of the box with far too much resistance, and others may fail in short service for the same reason.

I tried Platinum plugs for a while, purchased at a local discount department store for about $4 each. I don't recall the brand name, but they kept cracking the ceramic insulator off the tip in #1 cylinder, so I gave up on those. They might have been too high in heat range. Excessive spark advance is not an issue in my car with low compression.

Several years ago a club friend gave me a set of Halo spark plugs, model number H-9A. He was selling them, and he wanted me to give them a long test run in my MGA. I suppose he was looking for a rosy review to help sell the things, but I told him up front I don't play favorites so don't expect much. My original expectation was that the things might have a very long life, but otherwise no (noticeable) difference in function vs. any other plugs.

50,000 mile Halo spark plugs

They have been in my car for just over 50,000 miles now. I have never touched them except for occasional inspection during routine service. They have been working fine, running that nice sandy tan color for me, and they will stay in the car for as long as they continue to work.

Subsequent research has shown no upper limit for useful life of the Halo spark plugs, some having run over 100,000 miles, so maybe they will last forever. You can check out the following link for detailed information about Halo spark plugs. Keep in mind it is from the manufacturing company, so as nifty as it sounds it may not be revealing any opposing commentary.

From the WayBackMachine archives: http://www.halo-sparkplugs.com/halohistory.htm
New web site address: http://www.halosparkplugs.com