Hi Charlie;
Good question. A couple of items that commonly get overlooked are the exhaust system, and the welded steel engine mount.
Considering you had the prop resealed at the last annual and returned, that seems to indicate that the prop is in serviceable internal condition. I suggest you contact the prop shop that did the reseal and ask it for advice on whether an overhaul is needed.
A reseal order lets the prop shop make the call on the parts that need changing. In order to reseal the prop the hub has to be opened up and the seals changed. If wear or corroded/rusted parts are discovered while the prop’s open, then the shop will call to tell you what they found and their repair costs, or if there’s lots of wear and rust/corrosion it will urge you to overhaul the propeller.
Hartzell recently changed the type of grease it wants pumped into the hub at each 100 hour/annual inspection. The old specification was Aeroshell 5 or Aeroshell 6. Due to a fire at the plant in Illinois in June 2021 the production and availability of these greases has been severely affected. The old spec greases can’t be mixed with the new spec grease (NYCO 3058) so that’s another issue facing your decision to re-seal or overhaul the propeller.
I found a hole in one of the lower tubes of the engine mount on my 1960 Piper Comanche, so removed it and took it up to Loree welding since it was the closest approved engine mount repair shop. I chose Loree because it was close to where I live. It was much less expensive to be able to drive it there thatnit would have been to package and ship it.
My mount had so much internal rust that 7 tubes had to be replaced before it was airworthy. Other well known exhaust and engine mount repair and overhaul facilities include Acorn Welding, a Piper Flyer magazine advertiser; Aerospace Welding Inc, and WagAero.
You’ll need to take a look at the prop governor to try to determine the last time it was overhauled. It’s it’s also been 15 years, like the prop, I would send it to get overhauled.
I would also install new flexible engine hoses. Most flexible hoses have a life of 10 years. Type “Dakota firewall forward engine hose kits” into your favorite search engine for prices and availability. Aircraft Spruce and Specialty, a Piper Flyer advertiser will make up hoses too, although it appears each hose will need to be ordered individually.
Those are the big items. These, in my mind, are must do items when and engine is changed.
Best,
Steve
