Question on spark plugs

Sat Dec 22, 2012 6:41 pm

First off.We got several inches of the wettest,hardest to move snow I have ever run into. The poor Cub really struggled with it. Nw as to the plugs. I have an intermittant miss with a heavy load on the engine. Sopunds like ignition, but I am not sure. I have had this Cub for 12=years and havenot had to do anything to the ignition system or carb in that time. It starts right off and runs good otherwise. This morning I pulled one plug t see what it looks like. This is what it was like.
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These are the plugs that were in it when I got it, but I may have had them out once, I don't remember. It is a D-15Y. I went to the parts house to get new plugs, and they did not have the D-15. They had a 16, but the end did not protrude as far past the end of the plug as this one. Does that make a difference, and should I even go to a hotter plut. This one looks like it is burning pretty good, and I do not use the tractor for any hard wrk except plowing snow. Thanks, Roger
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Re: Question on spark plugs

Sat Dec 22, 2012 6:58 pm

Folks around here swear by Champion plugs in these motors, but we've had Autolite 3116's in our Cub for at least 30 years without a hint of a problem. I used to foul Champions mowing hay with a Super M like clockwork.

Any Champion from a D15 up through a D21 will work, but based on my experience, I would buy Autolite - they usually have them at OReilly...

Re: Question on spark plugs

Sat Dec 22, 2012 7:17 pm

Roger:

Ellie don't like D-16's but she is pretty partial to D-21's. 12 years and that is all I use now all year. We kinda has a similar storm - we got instead of 25mm of rain, almost a foot of heavy dense wet snow too. Ellie did real well during that storm. Plowed up a storm she did :big smile: . She hadn't run in a week or so but first pull on the starter - poof off she was to the races. I am not a fan of the NGK or Autolite plugs. Found they fouled too much.

Re: Question on spark plugs

Sat Dec 22, 2012 9:04 pm

ntrenn wrote:Folks around here swear by Champion plugs in these motors, but we've had Autolite 3116's in our Cub for at least 30 years without a hint of a problem. I used to foul Champions mowing hay with a Super M like clockwork.

Any Champion from a D15 up through a D21 will work, but based on my experience, I would buy Autolite - they usually have them at OReilly...


My experience with Champion plugs is much the same as above. Years ago I rebuilt a '41 John Deere B, my first rebuild, replacing the plugs with new Champions. Once the rebuild was complete I tried for days to get the tractor to run even having my dad come over to pull me to see if it would start because the hand cranking wasn't working. Finally my dad went out to the barn and grabbed a couple of old AC plugs and knocked off decades of dirt and grime and I installed them. First crank it fired up and ran like a top.

Years ago I was a very serious motorcycle racer (hence ricky racer) and would only buy Champions for my race bikes if nothing else was available. When I did buy them, I'd buy several hoping one of them would work. I have never had good luck with Champion plugs and still to this day only use them as a last resort. However with that being said, any tractor antique tractor that had old Champion plugs in them have never given me a problem.

Re: Question on spark plugs

Sat Dec 22, 2012 11:43 pm

i was always told that after a rebuild the engine pre lube you put on everything will foul out and actually ruin the first set of plugs. I alway start the new engine with a rag tag bunch of old junk plugs i have laying around and then put the new ones in once the timeing and carb are set and throw the old junk ones away.

Re: Question on spark plugs

Sun Dec 23, 2012 10:55 am

Champion sells almost all the plugs it manufacturs. Some are better than others. All depends what the retailer wants to buy.

Re: Question on spark plugs

Fri Mar 29, 2013 8:25 am

Even though this post is four months old I'd like to ask a question. I looked up on the Autolite site and they recomend 3116's, a non-resistor plug. They show this application for all Cubs, including numbered Cubs (with and without a mag), except for the industrial Cub which they show a 386 plug, a resistor plug. The 3116 is one range hotter than the 386. I've been using a set of 3116's in my 48 F-Cub for about 5 years and they've run perfectly. Like Rudi said you may want to try the D21's if you want to use Champion plugs (from what I could see they don't make a D21Y, a non resistor plug, but they do in cooler heat ranges). Like some of the others I haven't had good experiences with Champion plugs either. I got a set of 386's and like the D21's they are a resistor plug. Does it make any difference (non-resistor/resistor)? I ask because I see a Cub with a mag needs solid core plug wires.

Since I've re-ringed the engine I'm having some trouble starting it. I've been scratching my head on it for a few days. I was thinking about the plugs being 5 years old, they may not be firing under compression (it occationally sputters), and since they are five years old with quite a few hours on them, although they look like they've been buring quite well. I didn't check the compression before I tore it down and the old girl seemed to have good power before, but now I have between 80 and 105 psi before wearing in the rings. The plugs fire nicely when out of the engine. I haven't changed or moved anything related to the mag or timing. I was searching this site for some ideas that may shed some light on my situation and I saw this...
gusbratz wrote:i was always told that after a rebuild the engine pre lube you put on everything will foul out and actually ruin the first set of plugs.
Any thoughts?
Edit - to clarify, it hasn't started with the old 3116 plugs and doesn't seem to want to.
Last edited by Smokeycub on Fri Mar 29, 2013 11:28 am, edited 1 time in total.

Re: Question on spark plugs

Fri Mar 29, 2013 11:07 am

If you're worried about the lube fouling the plugs go ahead and start it with the old plugs. After an hour or two replace them with either one of the Autolites and have fun.

Re: Question on spark plugs

Fri Mar 29, 2013 3:02 pm

Well boys - fyi - I put some fresh gas in my pony tank and put in an old set of Champion D18Y plugs I had lying around (I thought maybe they don't make them anymore but I had an old set!??) and she fired right up, purred like a kitten. Do I have to eat my words about Campion plugs? LOL! I had to run it with various amounts of choke but I think that's because of a fuel flow issue with the pony tank and it still may be because of the plugs. Ran it for about 45 minutes, has great oil pressure now, no leaks of any kind. I'm letting it cool down to re-torque the head. It has a bit of a different exhaust sound now, I figure it's due to better compression and maybe because I adjusted the valve lash to .015", as near as I could tell they were at .020" plus or minus a couple thousandths. So there you have it, she's come back to life and sounds great, especially for a 65 year old tractor.

Re: Question on spark plugs

Fri Mar 29, 2013 9:50 pm

Ray:

Glad you got it to fire up and that it is running nicely now. Plugs are probably like oil -- everyone has a preference/opinion. IH recommended certain products, but there has been such a great advancement over the last 60 years it is hard to tell. Me, personally I like Chanpions but that is simply my preference for whatever that is worth.

Re: Question on spark plugs

Fri Mar 29, 2013 10:10 pm

I like the Champions , dont care for the Autolites , but that is like Ford and Chevy I guess

Re: Question on spark plugs

Sat Mar 30, 2013 11:23 am

i personally use autolights simply because thats what my local auto parts store sells, but i dont have a prefrence to any kind