Jan 28, 2020
This is the 12th post in our ongoing series on Project Super C. We are chronicling the rehabilitation of our 1954 Farmall Super C tractor, which has taken up residence outside of the Farmers Business Network office. If you are new to this series, please start with the introduction to the project in our first post.
This time, we’re going to start investigating the Super C’s engine, which we believe to be seized. The tractor’s model C-123 gasoline-powered engine has four cylinders, each with one exhaust valve and one intake valve. It is naturally aspirated and liquid cooled. The engine displaces 123 cubic inches (2.0L) and when new it produced 26 horsepower. For comparison to a modern engine of the same displacement, the naturally aspirated 2.0L engine in the 2020 Honda Civic produces 158 horsepower! Of course, our engine currently produces zero horsepower so we’d be happy to get anywhere close to the original 26 horsepower.
The easiest way to begin diagnosing the seized engine is to pull off the cylinder head, which will give us a look at the pistons and their enclosing cylinders. To remove the cylinder head, we must first remove the combined intake/exhaust manifold which is responsible both for bringing the air/fuel mixture into the engine and for venting the exhaust gases.
Inspecting the manifold revealed the first sign of trouble - the exhaust pipe, which is supposed to attach to the top of the manifold, is missing and very bad rust damage is visible within the manifold. Presumably the exhaust pipe was scavenged to be used on another tractor at some point, and rain water has subsequently been able to enter the manifold through the hole where the exhaust pipe had been attached. Here is a picture of the top of the manifold with visible rust damage. If you look closely, you can see big chunks of the metal inside the manifold are coming off.
The manifold is damaged beyond repair and will need to be replaced. More ominously, the water entering the top of the manifold may have also flowed into the cylinders by way of the exhaust valves (essentially following the path of the exhaust gases but in reverse), which could mean much more extensive rust damage. There’s only one way to find out -- we next unbolted and removed the manifold from the side of the cylinder head:
With the manifold removed, we were able to look into the intake and exhaust ports on the side of the cylinder head. The manifold connects to these ports.
The intake ports look OK, but the exhaust ports contain substantial amounts of carbon buildup and rust, as you can see zoomed in below:
The carbon buildup may have impeded engine performance, but that’s the least of our worries right now. The evidence of rust here makes it more likely that water flowed into the cylinders themselves.
The next step in getting the cylinder head off was to remove the “fan bracket water outlet” which bolts to the front of the cylinder head, and which allows coolant to flow from the radiator into the cylinder head (and then to the rest of the engine). Unfortunately, when we went to remove it, we discovered that it was broken where a bolt attaches, as shown below. Another part that will need to be replaced...
We removed the fan bracket, and then removed the valve cover from the top of the cylinder head. Underneath the valve cover, we found the rocker arm mechanism (part of the valvetrain) to be dirty, but it otherwise looked OK. We unbolted it and removed it.
Finally, the moment of truth was upon us. We unbolted the cylinder head and lifted it off of the engine block:
And the cylinders were revealed...
… to be in very rough shape!!! That is NOT what we were hoping for! We’ve got rusty water in cylinder 4 and there is some sort of rusty sludge in cylinder 3!! By comparison, the carbon and rust in cylinder 2, and the rust on the wall of cylinder 1 seem almost minor.
We flipped over the cylinder head, and the situation wasn’t any better:
The exhaust valve for cylinder 4 (at left) is open, which explains how the water flowed in from the manifold. As you can see, there is so much accretion of rust and carbon that the intake valve for cylinder 4 is completely hidden! While the exhaust valve in cylinder 3 appears to be closed, due to the rust in that cylinder we suspect that the valve didn’t seal completely, allowing water to slowly enter. The fact that all valves in cylinders 1 and 2 are closed is presumably why the rust in those cylinders is fairly limited.
Until this point in our rehabilitation project, we have gotten lucky and have been pleasantly surprised with the condition of the tractor given its years outside. Our luck has seemingly run out. At a minimum we will need to replace the manifold and fan bracket, which are structurally compromised. The rust inside the engine likely means the shopping list won’t end there -- join us for the next post and we’ll find out!
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Jan 28, 2020