So it did come down to a foreign object on top of the piston.  I wonder if it built up until it caused a knock, and the PO quit using it because of the knock.  In the early '60s I worked at a buick dealership.  Some of the customers driving high compression nailheads and never got over 20 mph would get knocks in their engines.  The easy fix was to take them on the highway and run them hard and blow the carbon out.  Once the service manager was going to fix a knock that way, but it must have had a cracked piston, because he blew the engine.  He somehow got it covered under warranty, even though the car was out of warranty. 

John - "The Hoosier Hurricane"

Just pulled the heads, large deposit of carbon on the bottom edge of # 2 cylinder, couldn't see it thru the spark plug hole, not much of a ridge, engine turns over freely now, looks like a good 312, not sure if I'm gonna build it or sell it. Gary

       

Gary, 55 Vicky, St. Germain, Wisconsin

 

Top ring on 2 or 8 hitting a ring ridge at the top of the cylinder?

John - "The Hoosier Hurricane"

Just looked at all the rod bearings, # 6 looked a little suspicious but they all passed, although they are all in real bad shape. Did notice that # 5 piston is new, looks like it's not been run much, if at all, from the bottom it has no scoring or oil splashed up into it, super clean. Mains tomorrow

       

Gary, 55 Vicky, St. Germain, Wisconsin

 

engines out, on a start up stand. Just had the wife try to turn it with a breaker bar, I can slide a feeler gauge between the piston skirts and the throws, so it's not hitting there. It stops in the same place on the balancer no matter which way I rotate the motor 

       

Gary, 55 Vicky, St. Germain, Wisconsin

 

Is it still in the car? Might it have something to do with the transmission?


Lawrenceville, GA

The distributor is out, I was pumping oil to the rockers, right side was put together wrong but I've taken care of that and I'm getting some oil to the top now. I'm gonna try to see the chain for a problem. Gary

       

Gary, 55 Vicky, St. Germain, Wisconsin

 

Something in the distributor gear or oil pump?


Lawrenceville, GA

#'s 2 & 8 pistons are all the way up when its locked, all valves are ok, #'s 5 & 3 are all the way down and are just missing the crank throws. Looks like I might be tearing this down further than I planned

       

Gary, 55 Vicky, St. Germain, Wisconsin

 

Valve hangine open and the piston hitting it?  Foreign object in a cylinder that moves from place to place?  I dunno.

John - "The Hoosier Hurricane"