oil fouled plug

I haven't been using the TO 30 much this summer. It has always smoked since resurrecting it in 2016 from 17 year damp storage. Its valve train was stuck from corrosion, and disallowing engine to be turned over by hand. I dumped several ounces of ATF in each cylinder letting it soak for a month before turning over by hand. Then before trying to turn over engine with starter the oil pan and valve cover were removed cleaned of sludge. Valve train was removed, disassembled, all corrosion & sludge deposits removed, and reassembled with all parts in same location as found. That was about 20 engine hours ago, fast forward to Nov 2020.

Over the 20 hours and four years, many spark plug cleanings were performed. My assumption was the engine probably has stuck rings, surface rust on one or more cylinder walls, and dead valve seals, not to mention the ATF treatment. Engine smoking gradually lessened with use to a few minuet long display after start up (worn valve and or bad valve seals) over the 20 hours. My thought was the engine was slowly self polishing the cylinder walls, perhaps stuck rings were also freeing up.

Number 4 plug consistently would oil foul needing cleaning after every use, the other three also slightly fouled remaining serviceable probably due to a too rich condition. I have leaned up the carburetor, and now no black smoke during rev-up.

Yesterday required a few hours of tractor use, I hadn't checked or cleaned #4 plug for last five hours of operation as the exhaust blue smoke has subsided greatly. That morning on start-up I noticed that oil pressure was just above zero, last time I ran it it was 10 to 15psi at 140* engine temp. To my surprise she was down four quarts of oil, and it hasn't been leaking it.

Once the oil was topped off oil pressure is back around 10 psi at idle, and 15-18psi above idle as shown on a new 60 psi gauge, and still not smoking real bad.

After yesterday's project finished I saw fresh oil puddling below #4 plug along the indented flat of the head, and dry as a bone above the plug up to valve cover gasket. Strange that oil appeared to be leaking from combustion chamber out around the plug's metal gasket ring. Never have seen that before.

So when I removed #4, found it to be solid caked with oily black deposit. Engine had not been misfiring, except for an occasional exhaust pop like a valve was hanging open.

At a minimum I need to replace valve seals. I did scrape clean the sealing surface that the plug's sealing ring seats on in hopes of stopping oil bypassing it.

I guess the best thing is to pull the head, check valve guide's condition, replace seals, and examine cylinder walls, and prepare mentally for a major engine overhaul.

Any tips welcomed.

Before I dig in to engine work that Wagner Loader #WM-4 has to be removed from the tractor. It's a total PIA to engine access.

It's common for spark plug gaskets to seep a little, nothing to worry about.

I doubt replacing the valve stem seals will do much good. They can be changed with out removing the head.

I suspect the oil consumption is related to stuck rings, and/or worn oil rings.

You can delay the inevitable by installing a non-fouler on the #4 plug. Not the best fix, but it will keep the plug clean enough to fire. Just keep a close watch on the oil. Running it out will greatly increase the cost of repair once you do go in.

As long as it has acceptable oil pressure, and the rear main is not hemorrhaging, you can get by with an inframe overhaul. The cylinder liners just sit in the block, easily replaced with new piston/ring/wrist pin cylinder assemblies. The hardest part is thoroughly cleaning the water jacket and seal area where the liners sit.

You will need to send the head out to be worked, and the rods out for new wrist pin bushings. New main bearings can be rolled in. Pay close attention to the crank thrust bearing, it is known for being troublesome.

And go through the oil pump. Be sure the drive shaft and gear are good, another trouble area.

Do a compression check with the throttle lever wide open.

Yesterday I replaced my old compression tester with new. This morning I checked compression on a warm engine.

It was cool this morning, and I had not started this tractor when it is cool or cold out before, but it started right up. It blew a lot of oil smoke for a minuet or two and cleared up. Let her warm up, pulled the plugs, bottom of air cleaner, and performed a compression test:

#1 = 130 psi down about 9% from the other three readings
#2 = 140 psi
#3 = 140 psi
#4 = 143 psi

I'm thinking #4 had a little oil from the valve train dribble into the rings over night and caused a little higher reading than the other cylinders.

I'm thinking the bottom end, cylinders and rings are in decent shape, and the oil control problem is a worn guide and or dead valve seal at #4.

There is an exhaust valve hanging up occasionally as the exhaust has has an intermittent suck back. There also is a pronounced tick-tick at the front top of the engine which I suspect to be from the valve train. Perhaps the lash is out of speck, or something. That rocker assembly was a corroded mess when I got the tractor.

I did notice the water pump pulley seams to have a lot of run-out but there are no coolant leaks.

Looks like I need to run the engine with the valve cover off to locate that ticking, and figure out how to fix it. Be it a bad bushing on one of the rockers or just in need of valve lash adjustment.

Hopefully #4 valve guide is OK, and I won't need to pull the head and get the machine shop involved.

Any Ideas welcome.