Knit-Picky...?

Are you saying that you don't have a clue as to what alloy is used to make up the cylinder sleeves in a taper-bore engine for which this thread is about?


Bob Brassel stated:

Jett uses special alloy aluminum for all pistons, and all sleeves

I would venture to guess that Dub Jett ordered a mill run in order to get the metal(s) with the material properties that he needed in order to make Jett Engines.

You have to have some clue as to what you're going to make something out of when you order material.

"Hello, ACME METALS... Yea, I need 50 1" bars of brass......

(Of course, what kind of brass would you like?)

"Well, Brass is Brass and I just need to manufacture a bunch of cylinders for some ABC model airplane engines"

(Oh, OK.... Will you be making an engine that has a taper piston and brass sleeve that changes with temperature or a fixed taper engine that uses a brass liner? You know, some types of brass, when overheated, tend to "bell mouth" and can loose taper...... )

"Lets not get "knit-picky" I want the yellow kind"

NOOOO Problem, 50 1" bars of the yellow kind brass will be delivered to your door


There is some good and bad information out there about break in proceedures for ABC type engines...... some info is a mixture of both. In general, a proceedure outline by an engine manufacturer should be followed as written. (They KNOW what kind of material they made the engine out of)

Other engine manufacturers have their noted proceedures. The proceedures depend a lot on materials.

Are you SURE that YOUR break-in instructions are correct for ALL taper bore model airplane engines?