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.
Silver Ghost 1645
Ghost cylinder
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?