Co-op E3 spark plugs

Hi, this winter I am going to try and get
my dads 47 Co-op E3 that has been sitting
for a few years running again. I am
planning on doing an ignition tune up on
it plugs wires points cap rotor etc. I was
wondering what are the best spark plugs to
run in it? And any of the other ignition
parts?

Thanks for any help
Smalltimer

(quoted from post at 08:58:25 11/09/23) Hi, this winter I am going to try and get
my dads 47 Co-op E3 that has been sitting
for a few years running again. I am
planning on doing an ignition tune up on
it plugs wires points cap rotor etc. I was
wondering what are the best spark plugs to
run in it? And any of the other ignition
parts?

Thanks for any help
Smalltimer

Click to expand...

I wouldn t. I would retain the good kit and only replace if/as necessary. Old kit was likely better quality than modern-day manufacture.

As you probably know, the E3 was a rebadged Cockshutt 30, and there's a lot more info available if you Google the Cockshutt. Manual seems to indicate Champion J5 plugs, which cross-references to an NGK B7S (or NGK 3710). I'd always go with NGK.

A 7 heat range in an NGK plug is a pretty cool-running plug - it's a common plug for lawnmowers and other hot-headed, air-cooled engines. If it were me, I'd probably go with one or two heat ranges hotter (B6S or B5S): Folks don't tend to work their antique tractors really hard anymore, so they don't get quite as hot as they might have back in the day when they were really put through their paces. Modern fuels also have a more uniform combustion characteristics. Both factors can lead to plugs fouling because they're running too cold. If this tractor gets some moderate, regular use working, I'd probably got with a B6S. If it's a show/parade tractor, I'd go with a B5S. If you're belting it up to a thresher and running hard all day until the exhaust is glowing red, I'd stick with the original B7S. These days you'll probably find only NGK plugs with 'BR' rather than just 'B' prefix (ex. BR6S rather than B6S). Not a problem: The 'R stands for a resistor-type plug: They add a couple k-ohms of resistance in the plug to smooth out the spark qualities (also helps control noise in newer vehicles with onboard electronics). Shouldn't make a difference whether you use 'B' or 'BR' on your tractor - only time it would make a difference is if you already had a failing ignition system (weak coil/bad leads) to begin with. Now you can also get 'resistor' type leads, which is a different issue: They add a lot more than just a couple k-ohms of resistance, and can sometimes cause issue with old-school ignition systems. I'd stick with the original leads if they're still good. If you have to replace them, I'd go with copper-core (noon-resistor) leads.

A hotter plug range is also a shade-tree fix for an engine that's fouling plugs over time because it's a little worn and burning a little oil: The hotter plug will burn off the oil a little better. Not really a 'proper' fix, but it works.

I don't think I'd hesitate putting a new tune-up kit in if you really want to, but keep the original parts around. As mentioned, some of the modern kits have some pretty low-quality parts. Also keep in mind a lot of new points these days come with an anti-corrosion coating on the contact surfaces which has to be cleaned off before they'll work. And new condensers are sometimes a hit/miss affair: some fail pretty quickly. Have even heard of some not working right out of the box. But most are probably just fine.

If it were me, I'd start with just replacing the plugs, give the points a cleaning and adjustment, and inspect the carbon contact on the dizzy cap (make sure it's springing properly and not covered in grime). That's probably all you need to do, and it'll serve you well for many years with those parts.

I'd recommend Blue Streak points. You can get caps, rotors and wires at most any auto parts store or order from Brillman. Just skip the Champions, I like Autolite plugs for mine.

Thanks everyone hopefully I'll get to this sometime this winter. I'll definity try plugs only first and clean the points. Also rebuild the carb with a kit.