Remember a couple of years ago I took my engine over to Avian to have it overhauled? Well that story keeps on coming. This time I can't put all the blame on them because I could have prevented this as well if I had done a lot more research. Anyway, when I dropped the engine off I asked them to convert it from an O-540 B2B5 to an O-540 D4A5. My research at the time indicated that the only major difference was the counterweights in the crankshaft which makes sense because the B2B5 is a lower horsepower engine. I wont rehash the horrible situation I had with the owner of that company but I mention this only because they are not an option to fix the problem I ran into this weekend. As it turns out there is one other major difference between the two engines...the B2B5 does not have the internals to run a constant speed propeller! What?!? I didn't even know that was an option on the 540! So at first this was a disaster for me since I expected the crankshaft was solid and it wasn't even an option to do a constant speed prop. After doing a little research I found that the crankshaft will indeed work for a constant speed prop and that all I have to do is replace about $1000 worth of parts. Oh...that and completely disassemble the engine and start all over again. Frustrating!!!! So you are probably wondering why I mentioned Avian in the beginning? Well I was hoping/expecting them to make all changes needed inside the case to convert it to a D4A5 and in fact they did give me a new logbook that says its a D4A5.
I'm not going to disassemble the engine so I decided to finish up assembling the various parts so I can preserve it while I decide what to do next. My current thought is I will have a mechanic tear it down and replace the parts. Its not a hard job but getting down into the internals of the case makes me nervous so I would rather have somebody who knows what they are doing do that part. Or maybe I will sell the darn thing and buy a new engine from Van's. Not likely on that option because I have all the things I want in this engine and I'm still about $15,000 less out of pocket. One final option I have is to install a fixed pitch Catto 3 blade prop. I've heard of other guys who do this and love it but I don't think I will go that way. The constant speed prop just gives me so much more takeoff power and with the gross weight this airplane will carry I think thats pretty important.
Anyway, here is what it looks like as of this evening. The pushrods are installed in the tubes but they are not yet gapped properly. The screws on the valve covers are just tight enough to keep the covers on and the oil inside but I did not torque those. I also did not torque the accessory case cover bolts or the sump bolts. These will all have to come back off. I did torque the cylinders on though because Lycoming wants these bolts torqued at all times. I've heard it has to do with case stresses and I've also heard it prevents main bearings from slipping when you rotate the engine. I don't know if either or both of these are true but regardless the cylinders are torqued on.
|See that little flat circle in the middle of this photo? There should be a gear spline there for the prop governor...that was my first indication that things weren't going well.|
|I have some exhaust port covers that need 2" o-rings (on order). Once those are on and the oil drain back tubes are installed I will be ready to fill this thing up with oil for storage.|