In article ,
"Jim Burns" wrote:

If you look at the cylinder bases you can tell if it is a wide or narrow
deck.
Narrow deck engines use interior hex nuts and possibly hold down plates to
hold the cylinder to the case. Wide deck engines have studs, regular hex
nuts, and thicker cylinder flanges holding the cylinders to the case.
Wide deck engines serial numbers end in "A", narrow deck engines serial
numbers do not.
Narrow deck engines are typically older, mid-60's and earlier.

I believe that
http://www.lycoming.textron.com/supp...Publications/s
erviceInstructions/SI1037M.pdf

shows your cylinder Assembly number to contain an "r" indicating angle
valves (not parallel) and an "e" indicating needing long reach spark plugs.

Jim


"Mike Rapoport" wrote in message
ink.net...
When I read about Lycoming engines the terms "wide deck", "narrow deck",
"straight valve" and angle valve are used to describe different
cylinder/case configurations. What is the GO480 in my Helio Courier?
Narrow deck? Wide deck? Angle valve? Straight valve?

Parallel-valve Lycomings have rocker covers that have parallel sides; on
angle-valve Lycomings, the sides of the rocker covers angle toward an
apex somewhere above the cylinder.

I lost a friend last year when his GO-480 threw a rod in his Pilatus
P-3. He hit a tree attempting to make an emergency landing.

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