Harry Ferguson TO20

[glenncooner]

this tractor run out of oil 3 years ago(jerry rigged oil pan plug fell out), stopped running but did not sieze. it runs now but runs rough when trying to power up or gear engaged. runs good at idle.
found correct plugs.

have it at competent mechanic shop now.
mechanic found the #3 spark plug would be flattened after running it for a while,he would pull the plugs and regap the #3 spark plug , same thing again---flashlight down sparkplug opening showed heavy black---could not see anything else.

we gave mechanic ok to pull head off for a look --can anyone anticapate what might be going on?

thanks in advance

 

[TonyinMass]

My guess is old age in general. a freind ran out of oil in an Omni a few years ago, it siezed up, freed up, and ran until the ball joints fell appart and the oil pan was on the pavement. You might have dried out the rings causing premature wear, but I bet she was due for an overhaul anyway. Well worth the cost and effort.

 

[Mark from the Fort]

I am assuming either carbon of something else is riding on the top of the piston and smashing the plug at the top... The angle of the plug inside the head is such a way that it would be hard for it to get smashed though...Hmm.
Are you positive the plug is correct and the threaded portion isn't TOO long and placing the tip in a dangerous area?
We would all be interested in hearing what your mechanic has to say.
Is it possible for a valve to drop down and do that sort of damage?
mark

 

[JerryMT]

ARe you sure you have the correct plug?( I use Autolite 3116 on my TO-30) The correct plug should have a 1/2" reach. Otherwise you probably have excessive carbon on the piston crown.

 

[glenncooner]

just so you know (thinking about what the problem is), i posted a query here about which plug to use, an AC or Champion. I took a copy of the reply to CArQuest-they actually had the spark plug recommened, and the computer had a notation that said, "agricultural use".
---If the #3 plug is fouling up due to incorrect plug, wouldnt all the plugs do te same thing?

thanks

 

[Jerry/MT]

Not necessarily. There could be some mixture distribution difference in the manifold, or a bad plug wire, or damaged plug, or a cylinder with a loss of oil control., etc, etc.
What does the fouling on the plug look like? If it is wet and oily looking, it's a due to a loss of oil control. If it's a dry fluffy soot, then it's too rich mixture locally.

 

[glenncooner]

Update-november 19
Mechanic pulled off head-lots of carbon in #3 cylinder, but probably not enough to crush spark plug over and over again---curious discovery, a #3 is welded up towards spark plug entry, out of way of piston-piston does not show wear at that point, so weld not interfering with stroke . mechanic says there must have been something that was mashing spark plug gap-but his hired guy probably missed it when pulling off head

--#3 spark plug was indeed wet when we first started working it before taking it to mechanic, all the others just carboned up even though all the spark plugs were new. i posted a previous discussion regarding correct spark plugs-i went with was recommended here--i will research that discussion again and post what i bought and is now in the tractor
--
sure appreciate this board, i would not have any perspective without it.

thanks -mgcooner