Blowing brown smoke after valve stem seal replacment -not OS

[Lump]

I just helped a mate replace the valve stem seals and cam belt on his car (Holden Barina Van - early 2000's 1600 SOHC). It seemed to work fine at first but it has started blowing brow smoke when revved (it had previously blown white smoke on start up). It doesn't idle high or hesitate or anything else - just brown smoke.

Is this likely related to the valve stem seals, the camshaft timing, or is it overfueling for some reason?

[UTERUS]

I've seen oil produce brown smoke before, but never from an engine.

Petrol or diesel?

[Yowzer]

Seen a 2008? model Merc coupe absolutely vomiting brown out the tailpipe. No idea what actually caused it, but I bet it's far from good.

[cletus]

was it sitting around for ages? rusty water shit in exhaust getting blown out?

[Lump]

Its a petrol engine, it was being used up until we did the work on it. Some coolant and oil may have ended up in the exhaust but its been used for a week or so - so I guess it should have cleaned out since

[jakesae101]

have heard of cat converters doing this but its actually blowing rusty crap out rather than smoke

[Bling]

or is it overfueling for some reason?

Old mans 2000+ turbo diesel navara did this when a intake hose split in half, was SPEWING smoke. Probably not possible to be the same problem... but double check there are no leaks maybe anyway on intake?

[Unclejake]

I think you may have left the valve lash tight on an exhaust valve and un burnt fuel is entering the exhaust. If so you need to sort it quick before the valve burns

[johnnyfive]

I'm unsure if that motor has adjustment, pretty sure it'll have hydraulic lifters?

How does it drive? Smoothly I guess? The smoke doesn't have a healthy looking metallic sparkle to it? Could be worth giving the CAT a look.

Otherwise that sounds weird alright.

[Unclejake]

I can't say that I know the motors Waimaks, so I will STFU.

[Mike-e]

UJ sounds closest to me so far, brown smoke is NOx caused by partially combusted fuel. pretty much the most harmful gas your car can emit

valve clearances deffinitely first port of call. you said it didn't smoke on initial startup right? too tighter valve clearance will still seal when the engine is cold, as the engine warms and things start to expand your valve(s) may not be seating properly.

failing that compression test. doesn't run EGR or anything retarded does it?

[Lump]

There no valve adjustment on the engine, and I haven't seen any metallic particles in the exhaust. I guess I'll check the intake system for leaks and have a look at the egr system (I'm assuming it has one as it pretty modern)

Cheers for the help so far, I'll let you know how I get on