[Loyalty to the brand of sparkplug one uses is similar to marque loyalty--everyone has an opinion. Some are based on experience, some are based on emotion, Ed.]
Let's talk about those OEM spark plugs! At the tech session I attended last weekend, I got to see some of the lodge plugs used for Alfa engines. These have ring firing; there's the usual terminal in the center, with four small tabs placed equidistant around the circumference of the rim of the plug.
Instead of a single arc spark, a doughnut spark is created, with the idea of producing more efficient combustion in the cylinder. Carlo (one of the brothers who owns Alfa of Tacoma) indicated that the engines were engineered for the use of these plugs, and that the use of a regular, gapped single-arc plug would also require one to consider the orientation of the plug so that the cylinders would still be balanced during combustion.
--Tess McMillan
Why use a sparkplug other than the Golden Lodge which is recommended by Alfa Romeo? What could be the benefits? I have had no problems using 2HL Lodges.
--Hans de Kok
The ring spark eluded to for Lodge plugs is most unlikely. The spark you see is merely ionized gas molecules (plasma), particularly oxygen molecules. These ions transport the charge from the negative electrode to the positive electrode because of the fluid nature of a plasma, in much the same way water conducts electricity. If the spark forms a ring (of plasma) there must be an external force, either electrostatic or magnetic to hold it in such a form. With large moving ferromagnetic objects (pistons, valves, etc.) this would be impossible, or at least highly unlikely.
My opinion is that the spark strikes from the center electrode to one of the tabs, the one with the best, shortest electrical "contact", when this contact gets fouled enough to make that not the case, the spark will strike between the center electrode and the tabs with the next best electrical "contact", etc.
--Stuart Thomson
I don't use Golden Lodge in my modified 2L Spica injected Spider simply because they do not deliver sound value for the dollar. I have used NGK B7ES for 15 years with extraordinary success. I can get them for about $1.50 each and they seem never to foul. The B7ES is the proper heat range for my driving habits (roughly comparable to the Lodge 2HL). Obviously, the reach of the plug into the cylinder a critical. Given the tight clearance between the top of the cylinder and the head at top dead center, if the reach is too long, the plugs will be damaged immediately upon crank over. A properly gapped B7ES has almost the exact same reach as the Lodge.
--Tom Muccino
There is no question that Alfa engines (the 4 cylinder at least) were designed to use Lodge plugs. Even my '67 Duetto owner's manual says to use them, so Lodge plugs are recommended by Alfa for best performance, not simply an attempt to decrease emmissions. Having said this, I don't use them. In my carburated cars, I've found that they more easily foul and in the Milano V6, other cheaper, more readily available plugs such as the NGK BPR6ES or BP7ES seem to work just as well.
--Rich Hirsch
It's a pain to have to mail order for something as common as a sparkplug. I've always been happy with NGK BP7ES in my 101 (Giulietta) car. I did put a set of Bosch Platinums in my GTV, but everything else was disappointing, including regular Bosch. In my humble opinion, Champions are crap. Stay away from resistor plugs, too. You don't need to hear the radio anyway. ;=)
There are two potentional advantages to the Lodge plug:
I think what most people have found is that with modern GOOD plugs, the added cost of Lodge is not worth it. However, some cars with marginal valve to plug clearances need Lodge for survival.
--Simon Favre
I'd rather eat dirt than use Champions in a car I care about. Bosch and NGK both make a good plug; AC plugs are often overlooked but really of very high quality. I was trying Autolite platinums the first time I burned a hole in a piston in my Milano; it probably wasn't the plugs fault but I've been skittish about Autolites ever since.
--Richard Welty
I found that a spark plug's side-electrode can actually make contact with an oversized intake valve! I was adjusting the mixture on my Spica-injected '74 GTV by doing sparkplug readings when to my horror, I started noticing abrasion marks on the curved part of the sparkplug's side electrode.
A quick call to Wes Ingram at Ingram Enterprises, AROC Tech Advisor, saved the day. He said to try to index the gapped open end to face the intake valve, which would greatly reduce the chance of any contact. He also recommended the NGK BP7ES sparkplug. I was using NGK BPR6EY, which has a V-groove cut into the center electrode for added performance. Both plugs extend equally into the head, but have different electrode configurations.
It seems this problem can be caused by any side electrode plug and since the original Lodge plugs from the factory have no side eletrode but are surface gap plugs, it must be real tight in there.
--Joe
I have a modified 2L with oversize valves. While the new head was off the car, I experimented. My new, big valves wouldn't even let a regular plug screw in! The short reach NGK doesn't even really reach the combustion chamber! The Lodge plugs fit as if they were really meant to be there...(duh!)
--Lorenzo Gonzalez
I would like to point out that a side electrode sparkplug can cause damage in Alfa engines with large valves. If the plug is fitted so that the side electrode ends up next to the intake valve -- watch out! That ticking sound won't be a tappet but the valve doing its best to break off the electrode.
When using such plugs, e.g., NGK B7ES, I use a marker pen to mark the position of the side electrode on the outside of the plug body and then ensure that the electrode ends up away from the intake valve and preferably both valves. I have a photo of a Champion N7GY (gold palladium extended nose type) showing a flat machined on the side electrode as the intake valve tried to chop it off!
--Les Singh
I think that Tess got the Lodge plugs "ring firing" mixed up with the Johnny Cash Ring'O-Fire spark plugs that are marketed on TNN.
--Bruce Giller