TO-35 rocker arms and compartment

Hey guys,

Right now I?m in the process of dis-assembling a TO35 that I bought. When I removed the crank case breather tube I noticed that it has some greasy sludge in the end. So, even though I wasn?t necessarily planning on dis-assembling the motor, I removed the rocker arm cover. When I did I found the whole compartment to be coated in this greasy sludge. Is this typical? Or have I just opened a can of worms for myself? The tractor ran well before I started disassembling, with the exception of a hesitation I associated with a governor or carb problem. Thoughts?

Hers some pictures

Yes, that's normal for an engine with a lot of hours.

Just clean it up, try to get out as much as you can. Once disturbed, anything that doesn't get cleaned out will wash down to the pan and be picked up by the pump. Try to remove instead of washing it down. A crevice tool on a vacuum works well, just don't clean with gas or anything highly flammable.

Some things that contribute to the sludge are:

Light use, never getting the engine up to temperature long enough to boil off moisture and crankcase contaminates.

Poor maintenance, not changing oil, dirty air cleaner, especially in extremely dirty conditions. There is a mesh filter inside the can that is often overlooked.

Operating without a thermostat.

Worn rings also allow more combustion gasses to enter the crankcase. This is a gradual and natural event. They don't necessarily need to be replaced at this time, may just not be what they used to be.

While you're in there, be a good time to set the valve clearance, and slosh out the gas tank with some E85 if you can find it. You can temporary a small fuel tank to run it, get it up to temperature. It really needs to be run after cleaning it out before adjusting the clearance. There could be sludge trapped under the ends of the pushrods that will give a false clearance when setting the valves.

I second the thermostat.
Once you find one, you might also desire to drill a small 1/16" hole in the flat edge of it.
This hole will facilitate the release of any trapped air behind the thermostat upon initial installation and also promotes a smoother transition from closed to open with a minor amount of coolant flowing through the hole during engine operation.
I would also replace the coolant with a high quality green coolant to ensure engine longevity.

I'll second the tiny hole suggestion for the thermostat. Tried it without the hole once and had a problem. The one I just put in my 35 had this issue taken care of. But the one for my 30 did not.

Has it sat for a long time, if so sludge is normal