This engine has been recently rebuilt! It looks to be in really good shape for an engine to be used for an overhaul makeover. You can see the honing marks in the cylinders and there are *zero* ridges. I'd put 3500 miles on it. The water jacket is pretty clean. The headbolts came out with a threadlocker on them. I am really happy with the state of this engine!
Now the ugly. There is in every cylinder what looks like a rust patina in the honing ridges. It is uniform, unlike my spare engine from the other thread. I don't know if this thing was rusted out and then given a superficial hone to get running or if the four years in the unheated barn in Wisconsin added the corrosion. Whatever it may be, I suspect it's the cause of the low compression. As far as old cars go, it would probably get better over time as the rings wear down the cylinder wall, but hey, she's getting a bore.
Inside the water jacket, through the holes, looks to have just a small amount of deposits, pretty good shape.
Houston, we have a problem. This is an indication, I believe, of what's causing the backfiring. Whether or not it's the valve or camshaft, I do not know. I'll bet you've seen this before. Is this what one would call a "burned valve" on cylinder #5? Note that #6 is brown, not ringed with carbon. Across the cylinders, they're pretty non-uniform across the cylinders.
