Is Besson History?

[iiipopes]

When you have metal moving on metal, eventually there will be wear, regardless of the type of metal or the lubrication. So, you want the part that is the most easily removable and rebuildable to be the "softer" metal. That's why the casings are (or should be!) hard brass and the valves either plated or something like monel.

In automobiles a generation ago, the crankshafts were (most still are) a hardened steel, and the bearings inserted in the journals and piston rods and caps were softer, called "white metal," as it is a lot easier to pull the journal caps and the pistons to replace bearings which are squeezed into place by bolting everything down than to replace a crankshaft. LIkewise, I'd much rather replate and lap in a new valve than replace, or pay for replacement of a valve block.

[sloan]

The same logic applies to valve guides. The King 2341 comes with metal guides; one of the things I had done on the first (annual) trip to the shop was to have them replaced with plastic. The plastic will indeed wear out faster - but that's a feature, not a bug!

[windshieldbug]

If I remember correctly, that was our standard answer to reported software problems... "It's not a bug, it's a feature!"

[iiipopes]

The same logic applies to valve guides. The King 2341 comes with metal guides; one of the things I had done on the first (annual) trip to the shop was to have them replaced with plastic. The plastic will indeed wear out faster - but that's a feature, not a bug!

Hmm. I never thought of the valve guides that way before. Good point!

[prototypedenNIS]

Well, King describes the metal valve guides as being better for students because they don't need to be replaced as often.
The plastic valveguide are supposedly better because they're quiter, but they get replaced more often.

I prefer the plastic due to the quietness but I still use metal because I don't see it to be that much of a threat to the safety of my horn, and I'm just too lazy to replace them.

[Highams]

I'm glad it's of interest.

Whilst the author is correct about the s/s valves v brass casings, another engineer told me that providing the valves & casings are well matched on manufacture, the wear is going to be minimal.

It certainly explains why on my other Willson 2900 (now 15 years old), the valves still have good compression and that I can really only use a Hetman light oil for daily use.

CB