I drove the cylinders up to Poplar Grove Airmotive a couple of weeks ago. At the time, it sounded like we would hear more soon and likely have back before long.
This week we received an update; the cylinders require more than honing and will require oversizing to remove the pits.
As it is more invasive, oversizing removes the pitted material and smooths it for operation. It also requires new pistons as there is more space than the original pistons moved.
While we are waiting for the cylinders to be ready, the aircraft restorer has been working on the baffles – repairing what we can and looking for new or replacement parts where necessary.
Engine baffles help cool the engine cylinder head and oil temperatures, which are a key part of engine performance.
Over the years, the baffles’ vibration and movement while the engine operates and repeated removal for engine access showing their age.
When the Bonanza was built, it had a different engine, a Continental E-185 with an electric propeller.
By the early 1970’s, my parents had upgraded to a Continental E-225-8 with a hydraulic propeller.
To modify, the baffles were cut to incorporate an air-oil separator.
The external dimensions of the engines are identical; internal changes added horsepower to the then-newer 225.
After the 225, Continental changed its engine designations to refer to displacement rather than horsepower. The IO-470 is a similar displacement and size to the 225.
When the initial conversation of what had to happen before the cylinders came back happened, baffles were not on our radar. We knew about the remainder of the annual to accomplish while waiting and about cleaning out the engine bay. Taking the baffles off as part of the disassembly seemed like an afterthought.
Only as the restorer has inspected them do we realize what can be saved and what must be replaced.
While the restorer was out flying the clipped-wing cub, I took a closer look at what he had been talking about with the baffles.
As they were cleaned up, it was easier to see what was wrong. The restorer has said that except for the baffles around the cylinder heads, they all could be returned to service until better ones can be found.
The restorer has cleaned them up and reassembled them to use as a template.
On another piece, top-drill holes were no longer doing their job to the point of looking like Swiss cheese on the back of a patch being placed over a cluster of holes. While not pretty, it is serviceable in the interim.
The front baffle has also been an interesting discussion; originally, one piece was installed at the factory, and it is difficult to remove with the engine in place. The restorer has formulated a solution to make it two pieces that can be attached for service without as much headache.
As this is an older Bonanza, finding parts is again becoming an issue. Yes, Bonanzas are still rolling off the assembly line over 75 years later. What comes out of the factory today is beautiful and shares similarities but is very different from my airplane.
D’Shannon Aviation, formerly Beryl D’Shannon, has great products, several are already on Sis, but they do not make baffles for anything as old as a Continental E-225.
Which salvage yards have been reached out to, and online searches have become an ongoing discussion.
As Oshkosh is a couple of months out at this point, being realistic about what will be able to be done before this year’s show is becoming paramount.
Baffles or parts for baffles will be on the Oshkosh list.
It’s a beautiful day to fly, I’m hearing Continentals and Lycomings going over left and right. We will have our time. It’s just not today.
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