WD45 smashing spark plugs

I received a call from some friends the other day asking for some help with their WD45.  As they told me, it was smashing the outer electrode of the spark plugs against the central electrode.  They said the tractor would run right at idle but would do the smashing act when revved up.  All of this was happening on cylinders 1 and 2.  Admittedly, I wasn't buying the story until I saw it happen.  After the tractor would start to miss, you could pull out the culprit plug and the two electrodes would be smashed together.  There were marks showing that something was striking the plug.  We ran it briefly without the two plugs and it sent something out the holes and then it started running right.

The tractor has Autolites in it and I have never used them.  We put in some new AC45s that I have always used with the same result.

What head is on the engine and what plug are you using?

when I saw the heading I thought you were advertising your new band.

its highly unlikely but what if there is a humongous layer of carbon on top of the piston? take a flashlight and look down in there. I don't know how much clearance there is between the piston and the electrode at TDC but guessing it isn't all that much. if two cylinders are doing it maybe there is a blockage in the water jacket causing uneven cooling and thus more fouling and carbon buildup at that end of the engine. I'm probably way off base here but just something to consider

I'm with ML on this one- unless someone's fitted some OTHER head on it (mebbie something from a buda power unit?)  the spark plug is in a 'pocket', such that the piston would have to 'reach in' and strike it from the SIDE.  "Clocking" the plugs would keep the welded-end of the electrode from being contacted, but I really don't think the piston comes close enough to strike it regardless... there would hafta be LOTS of crud in that cylinder to make anything hit the plug.  Only time I've seen that, is an engine that's sat a while, and mud-dauber (wasps) got in it.

If the plug is too long, the electrode just hitting the inside of the pocket, you should be able to turn the plug in, and back it out, and see evidence of contact on the plug, without ever running it.

My question is- why cylinders one and two, and not the rest...

What's the 'long' story of this engine-  how long did it sit, did it wind up full of water, or anything like that?  Did mud-wasps get in there and build nests in the intake or cylinders?

Another thing you can try... only turn the plug in about half way, and try it out, and see what happens.  Don't leave it that way, just try it to see if you get the same result.  If the cylinders are full of crud, running it without a plug, revving it up a bit, SHOULD blow a bunch, if not all of it... out the stack.

If they're mud-wasps, you could do something really crazy, but I've done it on a few (two of 'em locomotive) engines...  pull the plug, rinse the affected cylinder with water using a piece of 1/4" plastic tubing... run the water full-blast, and let water run out the plug hole, and when it stops flowing mud, crank it over by hand to get the worst of the water out, squirt oil in the cylinder, hand crank again, then start the engine without the plug in place, run for about 10 seconds, shut it down, put the plug back in, and fire it up.  Once it's calmed down, change the oil and filter, as there'll probably be mud and water in the oil, too.

The ngk non-projected plugs with gasket t 3/4 don't hit the back side of the plug window but does expose about, 3 treads to combustion.

Edited by mlpankey - 03 Apr 2012 at 6:59pm

If someone would like to see a 3/4 reach non projected NGK plug in a head beside a 3/8 reach plug on a head allis recommends using a 3/8 plug on just ask and i will post .

Thanks for your posts.  I thought this was an unusual problem so I made the post.  The engine is all standard WD45.  The tractor  has been used regularly through the years.  Since the problem only occurs in cylinders 1 and 2, it has to be that debris is moving through the intake manifold as one intake port feeds cylinders 1 and 2 and the other intake feeds 3 and 4.  I don't think it could be a valve or piston problem as it happened in both cylinders at the same time.  Their old manifold is starting to crack and I will bet some material flaked off and migrated to the two cylinders through the front intake port.  After we ran the motor without the plugs in 1 and 2 it has been running fine since.  Am I thinking straight on the debris explanation? They will pull off the head if it acts up again and I will report back on the Forum.  I enjoy puzzles like this one.  Thanks again. 

You have debris in the cylinder.  Or somewhere allong the way there has been some parts swapping and machining going on.  This story wasn't adding up and I looked at some old parts.

First picture is a a d17 head . the last two are of a allis wd head . No leroi head was pictured my leroi head is on my tractair .Sorry Rod B but your showing your ignorance in head identification . I can tell you a 3/4 doesnt protrude out of a d17 head either and it can run a projected tip 3/4 reach in Ngk and champion .  If i rememeber right the autolites and a/c plugs are longer with the champion being the shortest of all four brands but its been a while since I did the test with even Kent dakin helping in doing the same on a 45 head he was using. Kent felt that the 3/4 reach with the 3 threads exposed was causing a hot spot .

Edited by mlpankey - 04 Apr 2012 at 10:35am

Edited by Butch(OH) - 04 Apr 2012 at 11:11am

yeap i am thinking. either plug will work as long as the electrode doesnt get mashed when tightening it up . The shorter the plug is in the hole the more ignition lead the engine will want over the longer plug.

Edited by mlpankey - 04 Apr 2012 at 11:49am

the threaded body of the plug will never get hotter than the ground strap. The wd45 the wc and wd head allis recomends the 3/8 plug but you can put 3/4 in and if you use the longer projected tip 3/4 plug with a widen gap then the ground strap will mash on the back of the spark plug pocket anyone in can see that in the picture with exception of Rod B and Ray Charles. The hottest color indication from heated metal will be on the ground strap and can be read for ignition advance. Valve lift would make a valve hit the piston before a spark plug ever will .

Edited by mlpankey - 04 Apr 2012 at 1:01pm

Ah typical backpedeling stages of pankey.

Edited by Rod B - 04 Apr 2012 at 2:01pm