Intermittent blue smoke on startup

Hey guys, First of all thanks for looking. I have a situation with the 86 MR2 that I'm a little baffled about. Every once in a while, like maybe once a week or two (I drive it everyday), it will belch blue smoke on start-up for a minute then quit. Normally, this wouldn't be some big mystery to me as the engine is 26 years old with 170K+ miles on it. I would assume perhaps leaky valve guides or some other form of leakdown while the car sits. Maybe still the case.

The weird thing is there doesn't seem to be any rhyme or reason to it. 9/10 times it starts right up without the Bond-esque smokescreen. Sometimes the car has been sitting for a weekend, sometimes just for a night between commutes. The outside temps haven't been consistent either. Any idea what's going on?

If it helps, the car has a 4AGE engine (non-sc), same as the Corrollas of the same vintage. I did recently switch to 10w-40 weight oil after doing some reading about how the thinner oils lubricate in a wider range of temps.

Maybe I can just use it as an excuse for that 3SGE Beams swap I've been dreaming about. "Sorry honey, engine was smoking so I had to double the horsepower"

Worn valve seals will do strange things. Toyotas of that vintage are NOTORIOUS for it.

If it's not lacking power or consuming large amounts of oil, just drive it and don't worry about it.

I second the theory of valve stem seals. The Volvo has some worn ones. Similar case of puff of blue smoke at start up. Now, it's a cloud of oil smoke because of a blown turbo

I am a third on the seals. Had a Gremlin that the seals leaked so bad that I didn't dare let it idle too long or it would start fouling the plugs. Other wise ran great. Never did fix the seals, just added oil now and hen.

yeah, valve stem seals, classic symptoms of it. Chevy 305s are notorious for it to the point its just kinda an assumed. As long as it clears up after running for a minute or so it should be fine, keep an eye on your oil levels.

Well.... if you are in the market.... I do 4AGE head porting, and rebuilding

current job OST-016: - http://hachiroku.net/forums/showthread.php?t=28687

I had a Ford F-150 with a 302 that smoked on start up. The PO wasn't big on maintenence and God knows what he used for lubrication, but the oil galley retun holes in the heads were plugged. When I took it apart it looked like carbon sawdust in there.

Oil couldn't return to the block so it hung out in the heads. Upon start up the oil dropped down the valves into the chamber, yeah the seals were shot also.

Thanks for the responses! Yeah, it barely consumes any oil, considering it's age and the distributor is leaking significantly (I've been lazy about that one). It always clears up after a minute or so and there are no drivability issues. Honestly, I'm a little impressed with how the whole thing has held up after all this time and "abuse". I think I heard someone mention their MINI S was getting a little long in the tooth for dd duty and I had a private chuckle.

Oldskewl - I've been keeping you in mind in case I ever decide to make this thing a dedicated autocross toy. I'm curious about pricing though, so I'll PM you sometime.