Decarbonizing K241

[Bigsauce]

I had planned on decarbonizing the cylinder head on my 105 and have finally gotten around to doing it. While my engine now runs fairly well and doesn't die off anymore, I noticed that it was getting excessively hot and was vibrating the whole tractor, enough so that I could see bolts vibrating and spinning and the hood would vibrate along with the grill. I started taking apart the head and noticed that the cooling fins on the head and on the cylinder were pretty clogged up with debris(Curious as to whether this may have been the cause of the overheating). My next observation once I got the head off was holy moly there is a LOT of carbon built up on the cylinder head and valves! All of this carbon seemed fresh, it must have been since my new spark plug was coated with thick carbon. I also noticed the head gasket was leaking a bit of oil on one side. I'm in the process of cleaning the carbon off still and plan to pull the valves, clean them, and lap them before putting the head back on. It seems like the intake valve isn't seating properly, and that the exhaust valve has a bunch of crud on it in the breather box. Finally I also took apart the breather valve and noticed that it was thoroughly soaked with oil. I plan on resuming cleaning it tomorrow and probably putting it back together on late sunday if I have the time. Any thoughts, advice or tips are welcome. I was hoping to get some input on what else to do while I have it apart.

[Yosemite Sam]

Is that a heli-coil in the plug hole?

Clean the fins on the block while you're there.

Get a piece of thick glass and some 180, 220 and 320 wet and dry sand paper. Lay the 180 on the glass and sand the head flat, sand until the entire mating surface is shiny. Once it's flat do the same with the 220 and then the 320 (or 400) to get the sand scratches out. Keep wetting and rinsing the paper, glass and head. This is not a fast process, I usually spend a couple three hours on one.

Make sure you put the little hole in the breather on the bottom so the oil drains back into the engine.

All that black soot could indicate any number of things, I'm bettin that most of it goes away once you get the head sealed to the block.

[twoton]

Bigsauce, yours don’t look to bad. Good you’re doing it now. Like Yosemite Sam said, plane the head;

http://www.onlycubcadets.net/forum/s...&postcount=183

Adjust the valve stem to tappet clearance, don’t know if there’s a thread on here that outlines the procedure???

Check the points and adjust the timing (could be part of the vibration problem)

http://www.onlycubcadets.net/forum/s...&postcount=152

Do you put any additives in your fuel? There’s some thinking that doing so may help to reduce carbon deposits in the head. The following is a quote from Dave Kirk’s site;

“ I’m also a believer in Marvel Mystery Oil and use it religiously in the fuel, mixed at 2 fluid ounces per gallon of gasoline. It has been conclusively proven (to me) that hard carbon buildup on the cylinder bore top land area and in the ring grooves, is greatly reduced by use of this additive. I’ve talked with aircraft A&P mechanics who have praised MMO for how clean it keeps the internals of the air-cooled engines they service. This is convincing evidence that MMO is one additive that really works.”

Check your engine mounting bolts to make sure all that shaking hasn’t loosened them.

Good luck.

[Merk]

I would use a tap to clean the threads the head bolts go into. I would replace the head bolts. You can use Kohler head bolts or grade 8 bolts. The head gasket needs replaced too.

The clog cooling finds can cause the engine to overheat.

[Bigsauce]

Thanks for all the tips guys. Sam, that's just the plug hole no heli coil in there. I cleaned the fins, I'm going to have to use a wire brush to get the rest of the carbon off the cylinder and head, it's pretty caked on. I'm going to get new head bolts and washers later today. I'll be sure Clean the threads and holes for the head bolts. I also ordered new gaskets for the breather cover. I plan on pulling the valves today if I can find a spring compressor locally. Any ideas on where to get a piece of glass for the sanding? I don't have anything lying around the house. I'm going to check the home improvement store while getting the bolts.

[olds45512]

if you dont have a spring compressor you can use 2 pieces of wood. what i do is turn the engine till the valve is up the whole way then cut 2 blocks of wood that fit between the block and the spring, once there in you roll the engine back till the lifter is down the whole way and now the spring is being held by the wood, a light tap will drop the valve back down and the keepers will come off. once the valve is cleaned up just put it in and put the keepers back on and roll the engine to push everything back into place and remove the blocks. thats how rednecks get things done.

[coinman66]

U might be able to ask any auto parts store about renting or borrowing a valve spring compressor tool also.

[Jumper]

Usually the glass in your wedding photo frame is big enough. Whoops ! did I say that out loud ?

[olds45512]

Originally Posted by Jumper

Usually the glass in your wedding photo frame is big enough. Whoops ! did I say that out loud ?

[Bigsauce]

Sorry guys I've been swamped lately and haven't had the time to work on the 105. I'm finally going to have some time tomorrow to work on it. I decided to buy a small valve spring compressor since I ordered a valve lapper and compound anyway. I sanded down the head with a thick flat piece of wood from an old desk. I then made sure the head was flat by putting it on my glass desk and using a feeler gauge to check for flatness, and it turned out flat. So tomorrow I'm pulling the valves and inspecting them along with lapping them if they're within spec. I'll have some updates with pics once I get going on that.