More 1920 engine joy!

[Mark Gregush]

My 1920 had some leakage around the head gasket so decided to replace the head gasket, valve job and pan gasket because of leakage at rear main and leaving a trail up the driveway. 
Pulled the head, that's' where the fun started!
It has aluminum pistons installed, great right? Not! They are stamped 3.888 but let me describe the pistons and rings I can see from the top at this point: 
First off, these pistons have rounded over top edges and use lap joint compression ring. Ok nice. Again not! The lapped joint is so far apart there is a gap of just under 1/8" between the ends. While 3.888 is a standard size DB piston, the bore at the top of the block is 3.888/3.889. You can noticeably move the pistons back to front and side to side, number 4 being the worst of the 4. With the piston at BDC on the thrust side I am getting about 3.903 or about .004+ taper. 
Most engines I have worked on the piston size is stamped on them or at least the oversize is. So, I am wondering if these were made from piston blanks that were sized to fit the 3.888 bore and that is the number stamped on them or were someone's attempt to keep the car on the road and used what they had. (more likely the latter) Same thing with the rings, used what they had or were a ring that could cover a range of sizes, these just being too small. 
I had just done a compression test a few weeks ago, front to rear, 65-65-50-60. So, compression was not too bad. Number 3 might be low because there is some rust in that cylinder so is not sealing as well as the others. Actually, after I pulled the head, was kind of surprised at those readings. 
While I have not pulled the valves yet, at this point all I can say is they are really loose in the guides. 
I need to get the pan pulled so I can at least see what is going on with that number 4 and pull number 3 to clean the cylinder up some. 
While I know what needs to be done, that is not going to happen at this point with this engine. So will get things check out then button it back up and decide what to do next. I have to be able to move the car so can't leave it sitting where/how it is. I do have a December 1917 that might be ok for a temporary engine, I will need to check that out. 

[Mark Gregush]

Pulled the head on the 1917 engine, top end looks promising, but time will tell what the lower end is like. Interesting tid-bit, this engine has aluminum crankcase, bellhousing and whats left of the transmission case (was converted to stationary engine), funny thing is, both the number on engine and bell housing match, 163840 adding 30,000 to that number would be about car number 193840. The MPL shows Dodge started the pressed steel pan at 73457/74388 so doing the math that would mean this was about 119,452 cars after that.

[22touring]

Just wanted to let you know that I'm feeling your pain, Mark.  Luckily for me, though, my engine has always run great.  I replaced the head gasket once and the pistons and cylinders didn't seem to have much if any wear.  My engine was rebuilt in 1957 by a factory mechanic at the DB plant in Stockton, CA.  They had some kind of a 4-cylinder rebuild program going at the time.  My gearhead buddies keep telling me that I shouldn't drive my car around so much because I'll wear the engine out, but I am hoping they are wrong.

[Mark Gregush]

Decided at this point, just to put the head back on and keep using car as is till can check out the other engine and swap them. Not even going to drop the pan, there is a little sediment in it, but it's not too bad and don't hear any rods knocking, little piston slap at times, but no rod noise.