C-221 Intermediate Knock Update

Hey guys! Warmed up a little today and I had some
time so did a compression test finally...doesn't
look good! As follows:
1 - 90 psi, soot on plug
2 - 115 psi, wet plug
3 - 100 psi, soot on plug
4 - 0 psi, wet plug
5 - 0 psi, plug looked perfect
6 - 115 psi, plug looked perfect

Thoughts?? This was a good running tractor with
plenty of power prior to when it started knocking
two weeks ago. At first knock was only between 1200-
1800 rpms but now its all the time. What would cause
two dead cylinders like that?? Thanks for any
help!!!
 
Pull the valve cover and see what's going on there. If there's nothing obvious, pull the oil pan.

There is no such thing as "just a bad head gasket." You can clean it up and put a new head gasket on and it may hold for a while. Heck it might hold forever if you don't work the tractor, but there was a reason the head gasket failed.
 
Well with those readings i will say that you have a blowen head gskt between 4-5 , now normally they blow between 3-4 but i have seen a few that have gone on other cylinders. SOOooooo you will need to pull the head and have the head ground and valves done .
 
Well since i am not able to hear it myself to be sure here is what i think , once you get the head off i think you will find a lot of play in the pistons and a vary large ware lip where the top ring stops on the sleeve , in other words the sleeves are way past there life span and what you have been hearing is piston slap from when the piston changes direction .
 
My 606 ran well but was a gutless tractor for its size. If your 221 needs a lot of work, finding a 263 from a 560, a 656 or a combine would make a substantial difference in your tractor.

--Lee
 
OK thanks for the input. I'll be sure and measure everything once I get into it. It will probably be a few weeks, but I'll post back with updates. Thanks!
 
A leak down test could help you identify the problem before you tear it down. You turn each cylinder to TDC on compression stroke (both valves closed), apply air pressure, then read the pressure drop and listen for where air escapes from each cylinder: intake; exhaust; rings, etc.

I don't know if a blown head gasket between two cylinders would be enough to roll the engine off TDC or not, just be aware it could roll a few degrees on #4 or #5.

What octane gasoline are you running in it?
 
Be careful running it. My 221 began to knock; I ran it about another hour before pulling off the head. Noticed a couple of pistons were sitting low at top dead center. Turned out to be two spun rod bearings! Crankshaft was almost damaged beyond repair. Just sayin'. Hugh
 
When I had a knock it sounded like a valve problem toward the top of the engine but that all looked okay, When I got into the oil pan a rod bearing was spun and I ran it enough to ruin the crankshaft. With a slow running engine it seem to run pretty good but it did look like the piston was slapping against the heads when they were removed. Looks like you will just have to tear into it.Cleddy
 

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