I looked up what the chevrolet vega block was made of a few
daya ago. They used A390 with 17% silicon and etched the cylinder
bores after honing to expose the silicon as the running surface. It
is classafied as a high strength alloy. An article on the WIKI site
was of the opinion that the early problems with the vega resulted
from an undersized cooling system and oil losses resulting in
overheating and engine damage. The block was apparently capable  of
normal overhaul intervals. It seems to be the ideal material for a
one rotor end housing casting.I ran the same briggs and stratton
lawnmower for 22 years and 6 sets of wheels on the  same engine, and
that was an aluminum bore. I retired it when it needed the second
set of rings and still have it in the shed.This engine was run about
3000RPM and being air cooled ran hotter than I need in a water
cooled rotary. It might be interesting to research what alloy nthis
engine used.

george grimes

If it were that easy I think Porsche and BMW would be using it
instead of Nicasil.

Paul Lamar


George,
It seems to me that the process for machining the Vega and the ZL-1 blocks
was to hone to size. Then they fit the hone with cloth wipers and used a
special compound to lift a bit of aluminium for the surface. This left the
silicone for the rings to ride on. The pistons were tin coated. All was good
until the engine got hot for whatever reason (maintenance?. This then wiped
the tin off and transfered Al between the piston and cylinder walls. Game
over until overhaul. The solution then was to sleeve the block with iron
liners. This may work for aircraft as the rotors are iron. What is wrong
with the RB end housings other than they do not have the wide housing for a
3 or 4 rotor?
Dale Davies