Occcasional clatter and blue smoke at cold start

[uniberp]

1999 forester auto ej25 SOHC, with 1999 forester ej25 SOHC rebuilt top end engine.

Twice it has done this in 150 miles/10 days of driving since I put in the engine with the rebuilt top end.

Normally it is clattery for about 5-10 seconds. No smoke.

Twice it has clattered longer, and a sizeable cloud of blue smoke occurs, then is gone when the engine gets quiets.

The engine had a burnt valve prior to rebuild.

My thinking is that cylinder might have sticky rings as a result.

The question is, do I do something, like techron or the unmentionable "Cee-fome" which I generally dislike for any decent engine, or just let it run it's course and wait for the healthy engine to clean itself up?

Edited April 17, 2012 by uniberp

[bluedotsnow]

I' no expert but blue smoke is oil.... maybe its a leaky cylinder ring.....

[1 Lucky Texan]

one way to get occasional oil into the combustion chambers might be incorrectly routed breather and PCV hoses, since your had an engine swap, might be worth triple checking that stuff. Don't assume, actually check the routing. maybe look for oil in the throttle body?

[nipper]

How many miles?

Did the car ever overheat?

Did it clatter before the head was rebuilt.

 

 

Change the PCV valve as it can cause oil burning.

[uniberp]

No, car never overheated, got a pro-built-and-assembled engine with original shortblock and new top end. New PCV, new valves, seals, everything but rings and bottom end. Old engine had 2 burnt valves, which is why I suspect coke buildup in at least that one cylinder. No error codes, no other running anomalies.

It only happens at lower temperatures and then only has happenned twice, but is visibly and audibly obvious. It is not a "rich condition".

OK, I guess i answered my own question. I'm gonna maybe soak the intake immediately before the next oil change with techron.