sarah331
27.05.2021 22:54:52
Re: Spark plug reccomendation - NGK vs Champion for '64 40HP here
See full version: Spark plug reccomendation - NGK vs Champion for; 64 40HP
Re: Spark plug reccomendation - NGK vs Champion for '64 40HP here
Re: Spark plug reccomendation - NGK vs Champion for '64 40HP
The 1964 RD-26, RDS-26 and RK-26 and their 'Rude sisters all call for the Champion J4C (replacing the J4J) gapped at .030" for mainly high rpm use.<br /><br />If the engine will be operated ONLY at low rpm the J6C can be used but a better all-round plug for a mainly trolling engine is the J4C gapped at .040". That will still work for long runs at higher rpm but will improve the low speed/idle and reduce fouling.<br /><br />In summary, pretty much what Paul said. [links]
The difference between the J4C and the obsolete J4J is that the ground electrode on the J4J only half-covered the centre electrode. That is to say you can file the ground electrode back a bit on the J4C and turn it into a J4J. The exposed spark helps a bit with fouling, but not enough to really matter much. <br />J6C is a little hotter and is an optional plug on your engine. If you troll most the time, it might be worth trying. The J4C provides a safety margin in the case of overheating, etc. Too cold a plug and it'll occasionally foul. Too hot and it'll burn a hole in your piston.<br />Any TC-W3 oil is infinitely better than what that engine was run with in the past. Use whatever makes you happiest. I find some of the premium type oils either smell better or smoke less, so I use them.<br />I've tried the B6S as a replacement and found it was a little too cool (if I remember right). There was something I didn't like about it but I don't remember what exactly. I'm like DJ: if I weren't talking J/E engines I wouldn't be talking Champion. Don't bother with any high tech plug because if they do anything at all, it's normally improved for 4-strokes not 2. And most the tip improvements (iridium, etc) increase life which is a moot point on an outboard where they normally die of carbon fouling rather than electrode wear. here
Re: Spark plug reccomendation - NGK vs Champion for '64 40HP
I’ve always filed back the electrode on a "C" plug to mimic the old "J" plugs on old non CD ignition two strokes. I’ve always thought they started better, but that may well be wishful thinking on my part. more
Kyle Anderson
Trempeleau, WI
skanders@triwest.net
920-764-0501 here
Sorry to have to ask the group again, but until I become a better search engineer I need to rely on my friends at AOMCI. Looking for a thread or other input.
It is possible you may want to step down to a J4C, if the J6C is running too hot or you do a lot of wide open throttle running. After a few outings, check it. Should be a light brown colour. [links]
That is true, cut back electrode proved better. Ex on my 1973 Merc 25ss it came with polar gap Champ L78V plugs, for my racing (back in the 70’s) they were a problem. Couldn’t read for combustion conditions and the flooded a lot. Best plug was determined by many racers to be a Champ L61Y (NLA), projecting nose with factory cut back ground electrode. I saved 10 and still use them on the same engine at AOMCI meets great plug even over NGK BP8HN-10 supposed equivalent which is not cut back. No fouling, no flooding, ran great. Also could retard the ignition some with the deep projecting center electrode. more
Garry right on. I would index the plugs on the race engines. Would point the ground electrode as close to the center of the intake ports as reasonable. Usually in a range of 25 degrees up and down from center intake port. Wanted not to shadow the fuel charge with the electrode pointing toward the exhaust side. here
Does it matter? Just for grins, I filed a J6C into a J6J, and noticed no difference in performance whatsoever.
The test tank is one thing how did the modded L4J’s run when testing on a race boat and on the race course? Did you ever get rpm and speed readings compared to other plugs? [links]
It should be noted that the reach does not include the electrodes, or an extended metal shell. When custom-selecting a spark plug, the electrode length and projection should be included in the calculation when taking into consideration the clearance in the combustion chamber. [links]
Plug gap will depend on output of distributor and fuel being used. Most applications using methanol will be at .022" - .025". If your ignition sytem is a higher output, maybe able to go as wide as .030". Gas application should be .030" - .035". You should also consult manufacturer of distributor for their recommendations.
While 5/8" (16mm) and 13/16" are the two most common plug hex sizes, plugs can have a hex as small as 8mm or larger than 1". more
For double hump heads. Most popular for IMCA Modifieds. Recommended for alcohol. 14mm plug, .375" reach, 13/16" hex.
Champion Racing Series plugs include all the features of their conventional plugs, but are built with extreme engine conditions and durability in mind.
If you're a tuner or engine builder in search of the perfect spark plug for your current project, pay special attention to the hex size required. Remember to take into consideration not only the diameter of the cylinder head, but also the added thickness of the plug socket needed for installation.