I used the LA .46 exclusively to compete in fun fly events with my 40 Up-Roars. They are a lot of bang for the buck. Easy to operate and last for a lot of years. I have never worn out a .46 but the .40 was another story. I found them a useless engine but when someone gives me an old trainer there is usually a .40 hanging on the end. They do fly the plane but there is no OS factor in them at all. When they are worn out they spit out a lot of gray in the oil slime and start to rattle a lot.
On the positive side they keep running. I keep using them until there is enough metal floating around in them that they start to burn out the glow plug. Rebuild/repair, nope, they are just a toss and forget engine.
As john mentioned, the prop selection is a great help. I ended up using the APC 11X6 in the Up-Roar planes, the 11X4 in a trainer. There are better engines on the market but the LA .46 is a pretty good engine for the money. Bushing engines do like Castor oil but all I ever used in them was Power Master 15% nitro with 18% blended oil.