Smoking on startup, not valve seals or pcv. Help!

I've got a '93 b2200 that smokes on startup after sitting for a few hours. I assume it's oil that's burning, because I know what burning oil smells like. I have searched everywhere and it sounds like it should be either the valve seals, or pcv, so i replaced both, but it still smokes. If anything else, like rings or a head gasket, i thought it should be smoking all the time, but instead its just for a couple of minutes and then its back to normal. I have no idea what else it could be, so I thought maybe somebody more experienced than myself might know whats going on. I'm new to working on engines, in fact, replacing the valve seals was the first time I've ever even been inside an engine. Lol. Maybe I'm just missing something obvious, I have no clue. It also idles high sometimes, like the choke is stuck, but i'm pretty sure that's a vacuum leak, but i figure i should put everything its doing wrong so maybe somebody can help me. Thanks!

Unfortunately the rings on these little motors get too much carbon and gunk in and around them and will therefore get wedged into their ring grooves on the pistons.......cleaning them or replacing them is really the best solution. As the combustion chamber, cylinder, and piston heats up it will allow the ring to protrude from the bore and stop the oil slippage by them and therefore reduce the oil burning that is happening when it gets past the rings and into the combustion chambers.

This is my personal opinion here, but I can almost guarantee you, if you pulled the pistons, cleaned the carbon out of the ring grooves and put it back together, your smoking will be history. Of course it would be senseless not to install new rings while you had it apart, but it's the buildup of carbon and burnt oil, especially within the oil control rings, that is causing the problem to begin with. There are some top end motor cleaners that are sold to help clean the pistons and rings, but from what I've heard, they work only marginally. Cleaning the pistons and putting in new rings will give you thousands more smokeless miles.
Most of the Mazda 4 cylinders that I have rebuilt, I have re-used the factory pistons......they're a darn good product, so I will clean them to the nth degree and install new rings and they are good to go for another 100,000 more miles with new bearings and oil pump.

Here are a few pics I have taken showing how the rings are just too gunked up protrude from the grooves like they should.

This engine was not bad at all really....I have other pics (I'll find them and post the also later) that the compression rings were even bound up some.....look at the oil rings (with the spacer between them) on thes pics though.....this motor is now in my little red truck and it doesn't smoke any at all.

Okay, thanks! So pretty much, the oil control rings are getting so gunked up that they get stuck a little off center, then when it starts to warm up, it loosens up so it can kind of reposition itself centered again?

Earl - I think I'll remove the oil rings from one of my old pistons, clean it up, and see if the rings are then expanded out further than the piston edge like new ones are. That will test my theory of whether the oil rings get stuck, or whether their main issue is metal fatigue from age and heat, so they no longer spring out as much.

Sped - in either case, new rings or new pistons/new rings plus cylinder head work takes care of smoking, did for me (last October). I was inventive/cheap/lazy so I did that with the engine stilled installed in the truck.

There is a product called Auto RX, worth checking out. Doesn't seem to be another big gimmick like most of the other oil additive products out there, and is recommended by many members of bobistheoilguy, which is basically the engine oil nerd gathering spot lol. I used it in my Supra several years ago when it had a non turbo engine in it, but the engine didn't really have any problems to begin with, so no first hand experience with that. If it is in fact gunk holding up the rings, this product could very well help.

Alright, thanks guys! I think i'm gonna try the additive, because i cant have much down time with this truck since I drive it to work and school. I plan on doing a sbc swap pretty soon anyway, so dumping very much money into this engine seems kind of like a waste.

Just do your research on it first, it's been a long time since I have used the stuff and don't remember a ton about it. I do remember though that it is a rather slow/long term cleaning process, so don't expect instant results!

I just found out I'm not going to have this engine for but maybe another month, so i'm just going to put up with the smoking until i get my new one. thanks so much guys, if the new engine doesn't go through, ill replace the rings.

You read my mind,I had mine looked at for the same thing.Just bought it a week ago...I didnt wanna believe the mechanic,but geuss its true.If I use the Auto RX,or some marvel mystery oil additive,how long would you all say I can expect before rings go completey?It does smoke about 1 min until I burp the throttle to idle it down,then it stops smoking completely.