In the last installment, I wrote about our installation of the cylinders. Since then, the restorer and I have installed the push rod tubes and the rocker arms on the engine.
Like the cylinder assembly, the rocker arms are liberally smothered in assembly lube of STP and 40-weight oil before the process begins.
While working on the Cub annual, the restorer painted the push rod tubes for Sis’ engine to match the engine case. It didn’t look like a massive change to me, but after seeing them installed, it was worth the effort.
Sis is a 1947 Beechcraft Bonanza model 35, one of the first 1000 off the assembly line. For all intents and purposes, she is my big sister as I have grown up flying with her and now am her caretaker.
After installing the cylinders, the restorer’s comment about engine work being more intimate than the ruddervator process made more sense.
With the confined space of Sis’ cowling around the engine, focusing our efforts on one cylinder at a time, limiting the scope to what was immediately in front of us was easier.
As the restorer’s hangar was at another airport 30 minutes away, he became adept at talking through what would be needed for the next step and ordering as needed beforehand.
We still had issues to deal with and hiccups to overcome.
Like before, in the days leading up to the rocker arms and tubes being installed, the restorer reviewed appropriate manuals and made lists of items needed. Reviewing publications and preparing for each step with the engine reassembly reminded me of a surgeon reviewing and preparing before a procedure, visualizing each step, and mentally noting any issues that may arise during the act.
Our goal was to install the rocker arms and push rod tubes over the weekend.
The push rod tubes drain oil away from the cylinder while the push rods inside take oil to the rocker arms. The rocker arms open and close the valves.
Push Rod Tube Installation
As we began to install the push rod tubes, we realized some seals were inappropriate in the assembly kit provided by the engine shop and needed to be replaced, noting to follow up with Poplar Grove the following Monday.
So much for getting it done that weekend – we will adapt and progress as needed.
Each cylinder has two push rod tubes that hold intake and exhaust valve push rods. There are four seals (also called packings) for each cylinder. Eight packings would need to be replaced before installation.
Using a brush to apply the assembly lube to the end of the push rod tube, the restorer placed a packing on the end and repeated the process with the other end before installing on the engine block through a hole in the cylinder head.
The second push rod tube is installed in the same manner.
During the cylinder removal process, parts for each cylinder were placed in numbered tubs correlating to which cylinder they were a part of. The process is reversed for reinstallation.
Each cylinder’s intake and exhaust push rods were individually unwrapped and reinstalled in their proper location.
Rocker Arm Installation
The rocker arms are next installed on the end of the cylinder and the exposed ends of the push rod tubes.
As with previous parts, the STP and 40-weight oil are brushed onto the rocker arms and the rocker shaft, which rests in holes, called bosses, cast in the cylinder ends.
Care needs to be taken during the installation of the shaft through the bosses as while they are cast aluminum; they can be broken if not cognizant.
Using appropriately sized sockets from a socket wrench set, the shaft is guided through the bosses aided by the assembly lube.
We completed what was possible that weekend and waited for the remainder of the packings to finish the installation.
I was out of town the following weekend, leaving the restorer to make progress on Sis’ engine bay in my absence. He asked one of his airplane sons to help as a second set of hands is necessary for some parts of the process.
They installed the remainder of the push rod tubes and rocker arms onto the engine. Once all were done, the restorer would install the covers on the cylinder heads and the fuel injection lines to each cylinder.
Seeing everything put back together was a realization that progress was indeed being made.
As the engine is the heart of the airplane, time and care are necessary to ensure everything is done correctly.
Some days, significant progress is being made while others can be hard to see. Each step is necessary for the process.
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