[tack]

I have a 350 chev engine that smokes. It has good compression and 30k since overhaul. But it sat for two years. Could this be valve seals? Or maybe stuck oil control rings?
It smokes all the time. Any ideas before I tear it all apart. It didn't smoke before sitting 2 years.
Thanks

[nitrous_69stang]

I would pull all your plugs first and check and see if any off them are oiled down...just to try and at least isolate the problem before tearing into the motor. Could be a bad valve guide if that is the case then you can just pull that one head and fix it.

[1BAD80]

It would be good to do a leak down on it first, it will tell you if the rings were sticking. Sounds like the O rings dried up and leaking.
It would be cheaper to get the tools and fix them while on the motor. If you have the compression tester you can rig it up to air pressure to keep the valves up, a spring compressor is fairly cheap, and can even rent one for a day. You will be getting other ideas from some gearheads on your post.

[74huggerorange]

I would bet that after 2 years your valve seals dried and have harded, thus no longer doing their job. So put some new posilocks on there, after all if that's not the problem your not out alot of dough <img src="graemlins/mwink.gif" border="0" alt="[mwink]" />

[reddwarf]

if it smokes all the time, it is most likely not the valve seals

You probably have some bad scoring down in the cylinders.

[Toyguyz]

It could be several things from valve seals, to sludge build up from sitting and even cylinder scoring if you didn't squirt a little oil in the cylinders before turning it over after a 2 year rest.

I had a 351C sit in a Ranchero for a year that smoked when I got it started after it's 1 year rest. When I pulled the valve cover there was a thick build up from sitting. After cleaning it out and doing an oil change the smoke went away. Maybe your problem won't be as easy to fix, but I'd start by pulling the valve covers and taking a peak along with doing a compression test to get a better idea of what the problem might be before tearing it down.