1911 ROLLS-ROYCE SILVER GHOST
The latest job in the shop is this Ghost. On the list of repairs are
examine engine for lack of power, re-line the foot brake shoes, overhaul and
install a used generator from a 20's Ghost, and install two new tires. After
performing a leak down test on the engine I determined that compression was
leaking past both the valves and the piston rings. Dismantling the engine
was necessary to determine the extent of wear on the valves and rings. After
removing the cylinder blocks, I found the cylinder walls were worn quite
badly, with the taper gauge I measured .0045 taper on most cylinders and
there were also many rust pits in the cylinder walls.
There was a lot of sediment and muck in the water jackets.
Once dismantled it was fairly obvious why there was so much leakage
of compression past the piston rings. At some time this engine has sat
dormant for quite a while and moisture has got into the cylinder. It has
caused a lot of corrosion in the cylinders. The pistons also show heavy
scoring on the thrust side, picture opposite.
What is not visible in the above picture of a piston from the Ghost
engine is the wear on the ring lands and the wear on the rings themselves.
The flat of the rings is worn down about .005 thou which has left a very
sharp ridge at the outer edge of the ring.
All of the water passages and surfaces in the cooling system were
coated with a eighth of an inch of sludge. I suspect this was from use of a
soluble oil in the cooling system. Surprisingly the metal underneath was
very clean when this was scraped off. Perhaps using soluble oil in cooling
systems does prevent corrosion, but where did all this sludge come from?