CS 3-1 blows blue smoke

[hugh54]

Hi, Perhaps someone has some ideas from their experience with Listers.
I have a CS 3-1 that blows blue smoke and accumulates oil in the exhaust port which drips from the exhaust pipe. It's not being used to power anything and has no load when running.
The previous owner overhauled it with new mains, big end, rings and valves. In an effort to find out why it blows smoke I have pulled the head and barrel, and the rod to check the big end. The rings are good with the correct ring gap and ring to land clearance, bore is good and you can still see the cross hatching. Everything else looks like it's just been overhauled which, in actual hours running, in has I guess. So at a bit of a loss what to fix. I'm going to fit new rings and big end anyway.
I was wondering if anyone has any ideas. Perhaps it's blowby caused by not being run in?
Thanks in advance for any ideas.
I should have mentioned that the valve guides are good, no appreciable wear.
Cheers

[38ac]

Could be oil, could also be half burned fuel which also smokes blue and makes a black oil like goo in the exhaust. I assume you have not drowned the top end in oil? failing that  I would check three things. First one is the oil dipper on the rod. It should be turned so it knife edges into the oil. Lots of people turn them sideways which is wrong. Second thing is injection timing and lastly check the injector for spay pattern and pop off. If all that checks out find a way to put a load on it and get it warmed up. An engine in excellent shape or properly overhauled will have a clear exhaust from the first start and no matter if cold or part load. The more little things that are overlooked during an underhaul the more it will smoke.

[cobbadog]

After checking all of the info that 38ac has offered I was going to suggest to load it up. I have nothing here that can load an engine until I saw a thing called a Prony Brake which is for measuring HP on engines. I cheated and just found a good length of of hardwood, started the engine and put the timber under the flywheel and the more lift I gave the more load that went onto the engine. I did this on a small 2.5hp engine and could stall it but didn't. I believe it helped a lot in getting the rings to bed in.

[Diesel Engineering]

Sounds like bore glazing. Especially if the engine has been rebuilt with new rings and has never done any work. Also very important not to put any high spec oils into the engine as this will inhibit running in. Really don't want anything higher than an API CC mineral oil. If it is bore glazing you may be lucky and if you run for a good few hours at high load this may clear it. If not you will have to strip engine and manually de glaze the bore.p

[32 coupe]

"no load while running"
I would bet that's your answer.

[hugh54]

Thanks for all the good info. I thought about a glazed bore and that might well be the problem. There are areas on the bottom ring that indicate that it is not bedded in. Good idea about the injector too. I wasn't going to pull that but will now. I have the cylinder off now so will de-glaze the bore and fit new rings.
Thanks again
Cheers