K301AS piston question
 

Had some time today to start working on my 123 with a K301AS motor, pulled the head as I knew the gasket was leaking. The piston looks good and has .003 stamped in the top of the head.
So would it be that this piston and rings are .003 over stock size? Had one of the head bolts come apart so I will have some time before I put this one back together again.
Going to check the bore size and spend some time with the valves first thing first.
Had no power and hard to keep running is why I started down this road.

Thanks for the help.

With head gasket leaking , that would cause low power and not want to run right

.003 pistons/rings were available from OEM manufactures of various engines to correct a minor problem in the bore.
As the engines aged they were discontinued,
with .010 being the first oversize.

All that said it is was acceptable to use a std ring set on a .003 piston, if the .003 rings were not available and the bore was good.
But usually by the time the .003 rings are worn out, so is the bore and it needs to go to .010 oversize.
Also,
It was not unheard of to put .003 oversize rings on a std piston (when the rings were available) and filed to give the correct end clearance at the tightest point in the bore which was most always at the bottom of the travel.

Fix your head gasket problem as mentioned and you might not need to go with a rebore and new piston/rings.:bigthink:

Ol George, Thanks for your info, after looking at parts that I would want to replace if doing a full rebuild and adding it up. It looks like I will be doing the head gasket and check the head for flat, check/reset the valves as needed and see what I end up with. My 123 is a user so it only need to run, If it comes to it I will look into repowering it and not rebuilding the old K301 engine.

I'd rebuild that block in a heartbeat as opposed to a repower.
You should be able to do kit for $3-400, including parts.

Second the rebuild. They are torquey, robust engines. Plus, a cool piece of history.

I would like a rebuild if my wife didn't know about it. When it comes to "toys" hers are it the top of the list, and mine are some what down the list.

But some times she looks the other way if I ask nice.

She did tell me to retire at 65, and then got me a new 2020 Dodge truck as my Birth day/Retirement gift.
so I will keep her around .

pulled the S/G back end open today to look inside, ordered a repair kit to replace the insides after a good cleaning and some new paint on the out side.

I need to stop looking for trouble , but what would I do all day.

Rebuild it, just do it!
When done, finished and setting there in all it's newly acquired glory, not to mention the sense of accomplishment you will have, should mean something to her!!
Hey, I'd even let here drive it once in a while!!:bigthink: