swisstonihasher

Okay, difficult one to predict but here's my case:

New 2.5L block with forged internals, cossie head gasket, etc done about 2k miles since built.
WRx heads, done approx 30k miles but lots of oil changes during that time (about every 3k, honestly), polished ports and chamber modified to fit 2.5 - I've seen the work myself, very professional and inlets look big.
New Scoobyclinic SR46 turbo, done about 500 miles with run in.

Most of the time I get no smoke at all from cold start or running, just usual condensation when first starting but soon clears. 3 times now I've had her blue smoke, twice on startup, approx 3-4 seconds, different days, one cold (I think) one warm and another time after doing a short half throttle blast, slowed down into my road, stopped and she smoked again. Now the smoke isn't lots and is blue so oil related but not for long then clears. Any thoughts?

Could be valve guides, turbo seals or piston rings?

I've done a compression test cold and the compression is very good on all 4.

Henrik

iTrader: (5)

I've got a 2.1 and it very occasionally smokes blue on startup, but it clears immediately (i.e. old ford style blue cloud, but it goes within 1-2 seconds of start) and there's no smoke when running.

I don't think it's anything to worry about, as I've heard about lots of other 2.1's doing similar things.

I read a thread on here a while back that it might have to do with the extra 4mm of piston travel on the 2.1/2.5 engines, but I can't remember the specifics.

swisstonihasher

I was wondering if it was ring clearance to bore but she's done it twice whilst warm so shouldn't apply. Not over worried as compression is very good and I've got det cans so can hear any knocks or bangs and there is none. Just odd, would prefer an engine of that low miles to not do it.

Henrik

iTrader: (5)

yep, definitely... the first time it happened it scared the bejesus out of me, and it looks like you're driving some old banger when it happens.

MOTORS S GT

iTrader: (2)

How,s your breather system piped up, still into the oe inlet pipe, or catch can ?

Baz82

My 2.5 is the same , its done 40,000km since being built with new everything , reconned version 4 sti heads and a VF48. Wouldn't worry about it

Edit : A point mentioned above make sure your breathers are not piped to the intake

Bob Rawle

Probably valve stem seals, 30k heads should really have had a new set when the build was done. As a thought

cheers

bob

swisstonihasher

Cheers all, I really hope it's just the valve stem seals and wish I'd had them replaced at the time now but with all the oil changes I wasn't expecting it to be needed, ah well, live and learn