View Full Version : TR4/4A TR4 Sparkplugs

04-27-2006, 06:22 PM
Hi All, What NGK Plug is everyone using ? That is those who are using NGK plugs. /ubbthreads/images/graemlins/smile.gif Thanks, Mike

63 TR4 Surrey Top

04-27-2006, 09:00 PM
According to everybody that I have talked to about the subject, the best NGK plug to use is Bosch Platinum. I had a set that I put in last summer; this spring I couldn't get the car to run right, Bosch fixed the problem. For some reason, at least in Western PA, NGK does not perform well. The numbers can be found at the auto parts store.

04-27-2006, 09:23 PM
Just in case you're interested, I'm running Bosch Platinum WR7BP in my TR4, and I'm happy with them. No experience with NGK for comparison though.

04-27-2006, 10:13 PM
Why? Did Champion stop makin' the L87Y?(Or L87YC?)

Well, if you must, NGK BP6HS is the equivalent.

04-28-2006, 04:16 AM
Seems a lot of folks pooh-pooh the Champion plugs...but they work just fine on my 4A...

04-28-2006, 04:53 AM
Hey Mike,
This is probably the most touched on subject in the forum but here's my two centavos worth - I like Champions alot. I have had more than one bad NGK plug, at twice the price.


04-28-2006, 09:02 AM
The L87YC plugs are still in production.
What is happening is that they are not a very fast moving part so many parts stores are clearing them out of inventory. I just bought up all the remaining stock from my local guy this week.

If the local parts guy doesn't stock them they are available from a master distributor usually overnight (or so I was told by my parts guy this week). So all you need is to plan a day ahead. I think you will also do better working with a local parts store instead of one of the big box parts guys; Autozone wants to carry parts that they can turn over several times a year.

Andrew Mace
04-28-2006, 09:20 AM
Champion changed their numbering system years ago. The current number for the old L87YC is 312, but L87YC still appears on the box and in most cross-references. If you look up either one on sparkplugs.com, you'll see that this plug has a host of other applications in chain saws, motorcycles, ATVs, generators, etc. (oddly, they have NO automotive applications listed).

Count me as a Champion devotee who has yet to have a problem with said plugs; I actually never much liked Bosch plugs in Triumphs, although they seemed ok in Volvos.

04-28-2006, 10:28 AM
I have always used Champion in the past. The NGK's were an experiment that wasn't worth the money. I am only using Bosch Platinum this time by recommendation. If not happy or find that they aren't worth the extra money, I will certainly go back to Champion.

04-28-2006, 11:20 AM
just remember those numbers are for non-modified engines.

04-28-2006, 02:32 PM
Interesting. I've had pretty much the opposite experience from everyone else who has posted.

I still swear by NGKs and have had great results with them in many older cars. These were not the fancy "split-fire" or multi-electrode or platinum. Just the plain old NGKs.

I find these at about the same price as plain old Champions, etc. So if you are paying double, you might be buying one of the "special design" plugs or NGK's platinum version.

I recall seeing extensive comparisons of plugs, by brand, some years ago. Standard NGK was consistently at the top for reliability and overall performance. Multi-electrode plugs of any brand provided no improvement to, and in some cases seemed to harm performance. (They might last longer, because the spark will seek the easiest path to ground and switch to a clean electrode, if one gets worn or dirty. But, are they worth three or four times the cost of standard plugs?)

One thing that showed up in that old spark plug test was that a higher than expected number of plugs were faulty brand new, right out of the box. Some well known brands had 15 to 25% of new plugs failing. It wouldn't be fair or useful to repeat "good" and "bad" brand names now, all these years later. But these tests are what originally led me to use NGK.

Today, who knows? Maybe other manufacutrers have improved or NGK has let quality slip. Things change and tests should be rerun to be really useful.

Plain old Champions were okay, too, in my TR4.

Bosch Platinums didn't work at all well. The engine missed a lot at higher rpms, even with brand new plugs. This was with Webers, increased compression, but essentially a stock ignition. I have to admit the plug wires were nothing special and pretty old, too, and might have contributed to the missing.

On the other hand, I found Bosch Platinum did very well in several water-cooled VWs (GTIs, GLIs and Scirroco, all with electronic ignitions).

I'd have thought Bosch Platinums would also do well in my LR Discovery, with it's coil-per-cylinder electronic ignition. It ran well for a while, but the plugs died a very early death... less than 10,000 mi. That happened while on a road trip, so I put a set of Champion "Truck Plugs" in, that were all an auto parts store in a small town in Oregon had available for the car. But gas mileage plummeted (it's already bad enuf!). Truck plugs are a little longer, so I suspect they upset the gas flow in the cylinder. The only change to the Disco's ignition is an upgrade to Magnecor plug wires.

In classic motorcycles, standard NGK have been just about all I've ever used. They're in my Honda right now. Motorcycles seem to me to be a good testing ground for spark plugs, since they often run at higher compression ratios and higher rpms than cars. Also, older motorcycles have relatively primitive ignition systems and carburetion.

As mentioned, TR4 use BP6HS as the standard NGK plug. One or two steps cooler might be useful if the engine has a milled head and increased compression, as Rob pointed out.

Also, if you have modified the ignition in any way, that might call for different plugs or different gapping of the plugs. I plan a conversion to fully electronic Mallory ignition on the TR4 sometime, with a far hotter spark than the points could ever provide. Also, a multi-spark ignition will usually allow for much greater plug gap.

Anyway, some spark plug experimentation will be called for. Perhaps when I dyno the TR4 for the Weber tuning I'll run a little experiment with spark plugs at the same time. It would be interesting to just have 4 or 5 different sets on hand and do some quick swapping, just to see if there is any difference. Of course, the proof will be in the long haul.

Meanwhile, heck, if you don't like em, send your NGK my way! /ubbthreads/images/graemlins/wink.gif