From: Dave Baker
Newsgroups: rec.autos.tech
Date: 20 Nov 2001 03:08:09 GMT
Subject: Re: How come this engine sometimes pours out smoke?

>Subject: How come this engine sometimes pours out smoke?
>From: jaybird@nmia.com  (Tom Baker)
>Date: 20/11/01 02:18 GMT Standard Time
>Message-id: <jaybird-1911011818560001@dialup299.nmia.com>
>
>The engine is a 4-cyl. 22-RE engine in my Toyota 4WD pickup. It was
>completely rebuilt by a local engine shop about a year and a half ago
>(just off warranty now, of course).
>
>A few times a day, after the truck has  been driven a while, and after it
>has been sitting idling for a few minutes--usually after waiting at a
>stoplight-- dense clouds of blue-white oil smoke pour out of the exhaust
>pipe. I mean REALLY dense, as thick as a smoke screen. It happened twice
>today while I was driving around town, and one time the wind was behind me
>as I started off, and I was engulfed in this smoke and had to drive blind
>for a moment. When it goes the other way I blind other drivers with it.
>
>Then after driving twenty or thirty seconds more the smoke disappears and
>all is normal again; no trace of smoke is seen coming out the pipe until
>the next episode. The truck runs great, smooth with lots of power,
>although it does stutter a little while the smoke is burning out.
>
>Does anybody know what could be causing this occasional smoking, and how
>might I fix it?



There are four main ways that oil can get into the cylinder to produce smoke
unless anyone else can think of others.

1) Up past the rings if there is excessive ring or bore wear. This normally
creates smoke under heavy load. Unlikely to be your problem but may be
contributing to 4).

2) Down the valve guides. Normal symptoms are smoke on first start up after
sitting overnight and after periods of deceleration such as going down a hill
with the throttle shut. Unlikely to create really dense clouds of smoke and you
don't mention a problem on first start up so probably discount this one too.

3) Via the head gasket if there is a blow between an oilway and a combustion
chamber. Likely to cause problems under all driving conditions especially when
the throttle is closed and then reapplied. Unlikely to be your problem but a
compression or leak down test would help eliminate it.

4) Via the inlet manifold from a breather designed to recycle and burn
crankcase oil vapours. If there is severe blowby and/or a blocked breather
somewhere else and/or an overfilled sump this may be pumping a fair quantity of
oil into the manifold or air filter. Possibly this is collecting and only
running into the engine during idle conditions. Sounds the best first bet. Have
a look in the air filter, manifold and butterflies for oil and check the engine
breathers are clear. Bore wear not remedied during the rebuild or perhaps a
very poor quality rebore might be contributing to this.


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