Date: Wed, 1 Nov 2006 11:08:13 -0600
Reply-To: John Rodgers <inua@CHARTER.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: John Rodgers <inua@CHARTER.NET>
Subject: Re: AMC heads (part 2)
In-Reply-To: <d06415073095105d702ce44f85507027@bluemarble.net>
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Neal, interesting post!
I never knew that the V-dub engines had sodium filled valves.
Interesting info. I note our comment about the bronze/silica balve
guides - I suspect that is what was in the aircraft engines in my day.
Changes in fuels - especially the elimination of lead compounds as
lubricants for the valves in their guides on the combustion side of the
cylinder - resulted in changes in guide materials. Engineers had to come
up with something that would not wear out given they no longer had the
lead compounds as a lubricant.
You mentioned "sandblasting". Aircraft cylinders are a combination of
steel cylinder barrel threaded permanently into a cast aluminum head so
that the cylinder assembly is all one piece - including rocker bosses
for the valve rocker shafts. Cleaning that combination of steel and
aluminum was a challenge. We cleaned a lot of cylinders and cases, but
it was a rare day that "sandblasting" was ever applied. Instead, it was
"beadblasting". One had to be very careful with the sandblasting that
was done because the moving sand took off so much metal. Had to be very
careful Beadblasting took a bit longer, but the materials did not remove
metal. Walnut hulls were heavily used in the aviation industry. There
wasn't much they would not strip off.
This is all interesting stuff.
John Rodgers
88 GL Driver
Neal Barrentine wrote:
> I haven't posted to the forum for quite awhile, but was very interested
> in this thread. In 1980 I worked at the Bug Haus in Seattle where one
> could buy a 1600 dual port long block for $369.00 exchange. We sold
> over 365 engines a year, and each one of them had sodium filled exhaust
> valves, three angle valve grinds, and the valves HAD to rotate in the
> guides, which were a bronze/silicone alloy. My job was to pull the
> engine, dismantle and inspect it, clean all the parts, sandblast the
> heads, intake valves and valve covers, press out the valve guides,
> paint the engine tin and valve covers. The owners did the easy work-
> one assembled the rebuilds, and the other did all the machining. If one
> of them was absent, then I got to cover for them. My favorite job was
> running the mill machine, especially fly-cutting heads, but I learned
> the most about physics from grinding the valves and seats. Heat
> transfer is the key to long-lasting heads, and the grind and rotation
> of the valves are the key to heat transfer. I had to throw in my two
> cents, as reading this thread brought back good memories. Have fun,
> Neal
> Neal Barrentine
> Bloomington, Indiana
> 1986 GL
> 1960 Baja Bug
>
>
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