Right, i sometimes get a puff of blue smoke on start up, depending on how iv been driving.
Now it would smoke for like 5 seconds and then clear, this is werther its a cold engine or even after say 1-2 hours after driving.
This mainly happens if i have driven the car on boost.
I have tried driving the car off boost for a few weeks and it stoped smoking.

-Oil level is not to high (Just under full mark)
-I have fitted an oil catch tank and vented breathers to atmosphere
-Cleaned out all boost pipes and intercooler
-No after market dump valve, just standard Recirc
-No blue smoke on boost
-No blue smoke on engine over run
-No blue smoke on normal driving conditions
-Car does burn oil, but nothing excessive (about 1 litre per 1000 miles)
-Oil used is millers CFS 10/40
-Car drives/boosts well and holds boost well

Bit about the car...
Its a 1999 Version 5 Type-R
standard apart from decat, full system and panel filter
70ish k miles
I have recently rebuilt the engine due to spining a bearing, i rebuilt the whole engine, all new gaskets, seals, new valve steam seals, rings new sump
new modine the lot everything new!
Done over 2000 miles now since rebuild
(just for the record, it used to blue smoke the same before the rebuild)

Uprated oil pump
V9 crank and ACL bearings
Cosworth baffle plate
25 row Mocal oil cooler and stat


What it could be....

Turbo? (The turbo says IHI VF28 on it)
When i done the engine rebuild, i split the turbo where the clamp is, and inspected, it seemd to be dry, no impella play either.
Faulty steam seals? (as stated above, these were replaced when i rebuilt engine)
Worn valve guides?
Cracked head?

Some help/advise/ideas please

 

sounds like it could be all or none lol however have you taken the turbo off and inspected it for wear since the rebuild ??

does it misfire at all ???

and did you get the heads tested on rebuild ???


i will admit right now to not knowing a lot about impreza engines however i have 14 years of mechanical and body know how.

and the items you listed it could be would result in constant smoke,overheating or misfiring cant see me self how its only for 5 seconds if it is one of the above

 

No, not removed it since, cant see what its gonna acheive by removing it again, as its been the same ever befor the engine rebuild.

Nope no missfire, spark plugs nice and healthy light brown colour

No didnt think to get heads pressure tested as i was convinced the steam were the problem.

No over heating problems.

Start it up, then a puff of blue smoke comes out the exhaust, then just a tad more for a few seconds till the oil that is burning has cleared....

 

well first thing you should do when you take the heads off any car is get them pressure tested and scimmed if need be so you know there in perfect order but as for your it could be worn turbo seals or blocked breathers

 

stem seals or tubby, take the pipes off the intercooler and check for excess oil.
i think with stem seals they tend to leak overnight so there is a puff of smoke in the morning, i used to have an alfa boxer 33 , virtually the same engine, they didnt even have stem seals and they burnt a little oil in the morning.

if it was me i wouldnt worry too much unless it gets worse, thats if it is stem seals( correction it shouldnt be stem seals then if youve replaced them)

isnt the crankcase breather a one way valve, sometimes they can stick and that causes blue smoke on a starlet anyway.

 

No, breatheres are not blocked, if your breathers are blocked your crankcase pressure would rise and force oil out of every orifice.

Theres a mist of oil the the boost pipe...

Im not worried too much about it, but its pi$$ing me off, i dont want it to puff out blue smoke on start up.

I might remove my turbo up pipe and start it up, if it smokes from the headers then its engine related, if it dont smoke then its gotta be the turbo i would of thought...??