View Full Version : TR4/4A tr4a plugs

07-31-2012, 04:37 PM
Put in new cap rotor and wires. Did a quick search on plugs looking for any recommendations. I don't want to start any trouble as I know plugs can be a personal choice, but any suggestions would be appreciated. Currently has champion L82YC.


Geo Hahn
07-31-2012, 05:06 PM
The Champions are what I have used for decades.

...I don't want to start any trouble...

Probably no trouble, but also no consensus.

<span style="font-style: italic">Randall is correct - L87YC (aka 312) is what I use.</span>

07-31-2012, 05:15 PM
I think L82YC is a bit colder than the stock plug (recommended Champion equivalent is L87YC), but should be fine as long as you don't have troubles with fouling.

I use Bosch platinum WR7BP, but I can't really say they are any better with a stock ignition system. Back when I was running a MSD 6 ignition on my TR3A though, conventional plugs would erode rapidly while the platinum plugs seemed to stand up much better. Ken G. (British Frame &amp; Engine) once wrote that they saw better numbers on the dyno with the BP plugs, but I can't say I noticed any "seat of the pants" difference.

07-31-2012, 07:25 PM
After having done what they called "drivability" in the auto repair business for some 35 years, I've learned the hard way that the plugs the engine was designed around work the best. That being said, I have also learned that NGK makes a superb spark plug with an extremely accurate and dependable heat range numbering system.

Andrew Mace
07-31-2012, 08:00 PM
I've much more experience with the "Small Car" (Herald/Spitfire) engines than with the wet-liner fours, but for over 40 years now I've done very well with Champions. I will admit that the NOS K.L.G. plugs I'm running in my '67 Herald right now seem to be ok, too, but I'll probably switch back to Champions just to see if there's any real difference. :wink:

08-01-2012, 12:07 AM
Champion L87YC

08-01-2012, 08:20 AM
Thank you gentlemen. Getting real close to the point where I feel like she's running well enough to load all the spares into the boot and :driving: :driving: :driving: