Any chance that I don't have to get the block bored out?
 

This is from my Geo. I pulled the pistons last night and that chunk fell out. I am guessing that it had been broken for a while so I am not sure why it didn't fall into the pan. The bore feels smooth and I cannot visually detect anything that indicates there was ever a problem in there. I have no idea what it costs to get the block bored. Any comments or suggestions?

http://www.lightweightmiata.com/geo/head/head08.JPG

you probably need to get the block honed, not bored. if you bore it, you'll need OS pistons to go back in it. the condition of the cyl bore is the determining factor, despite what the piston looks like.

would it not be simpler and more cost effective to source a junkyard or pullapart motor?

Probably. I already bought a rebuilt head for the thing. If I buy another engine I am afraid that it will be 40 lbs compression just like this one (all of them are):

http://www.lightweightmiata.com/geo/head/head01.JPG

Throw a caliper in there to see if you are out of round and if it checks out a quick bottle hone and a new piston you should be ok.

Well, just got back from the machine shop and they said it was .003 out of round on #1 (the broken piston was in #3). I guess I wasted my $37 on that flex hone because cylinder honing is included in the $80 charge to bore the walls.

This project is getting expensive. If gas goes to $50/gal it will only take me a few years to pay for all of this!

Well, chalk it up to a $120 bore and hone, which is still a good deal.