I noticed last night my Sapphire has started to smoke a bit on overrun,taking it out today and it seems ok at start up but again quite a bit of smoke on overrun and giving it a rev from idle once i stopped it gave a few puffs and seemed to clear at normal driving speeds.

A bit of googling suggests valve guides maybe stem seals or the turbo could be on the way.

Being new to the Cosworth engine what's best to start with?

It's meant to be on a stand next weekend at the McRae rally challenge so I could do with it being something simple I hope.Being an old Ford though I doubt it haha

 

Check what oil it is running, then get a cylinder leak down test and compression test after you have used it in anger on decent fuel. After that it could be rebuild etc but use it well first.

 

Black or blue?

 

More blue colour I'd say which suggests it's being burnt doesn't it?

Might just see if I can get someone to have a look.Wife will go nuts spending more money on it just now

 

No smoke on start is a good sign so rules out stem seals and guides.

Overrun could suggest turbo. Remove turbo to cooler pipe and check for oil.

This oil finds its way into intake manifold and on overrun which creates vacuum sucks oil into combustion.

What breather system are you using and is it clean?

 

It's a bailey breather system.Not had a look to see if it's clean or not but that would be easy enough after work tomorrow

 

I think I'd be more worried if my Cossie didn't smoke

 

I spoke to someone about it today and he pretty much said the same thing.

What's coming out of this thing though is a bit more than just the usual wee puff here and there.

Going to have a look at the pipework and breather system and try that today before making the call for surgery on monday

 

can you even get a cossie that don't smoke and stink of fuel and oil

 

Mine smoked on overrun too recently and the turbo was gone. No smoke on startup either. I'd check your turbo for play and the return pipe to intercooler for oil, as said above.

Philip.

 

There's no oil in the turbo to cooler pipe at all,slight play in the turbo though.

Breather system cleaned out too although it wasn't too bad but took it out a run and still smoking like a fucker after a good booting.Still pulls very well though

 

smoke is fine, especially a bit of black on a cossie but i have never been a fan of blue lol.

 

If it was black i wouldn't really care about it but this blue stuff worries me a bit,well not so much worries me but it scares the shit out of my wallet

 

agreed, I've been there probably 5 times over the years and always seems to be the dearest possible thing, i think 4 of them have been a rebuild and one turbo.

 

Coloured smoke is never normal (if the engine is on operating temp!). When ppl agree and say "it's an old car, so it's normal" so they think it's not worth it to fix such an old car IMO.
Blue smoke is a sign of unburnt fuel or burnt oil. You can fix this problem, never mind how old the car is, it is never normal, at most tolerable

 

Have a leak down test as I had similar on my 3 door it smoked on over run and cleared under boost, I tried all the usual, and it ended up being a bit of everything but biggest concern was bore wear. Ended up with full rebuild and it hasn't really used any oil since. Expensive but worth it if keeping car. Once I knew what it was I just started collecting main parts a bit at a time then pulled engine out over winter and got it done.

 

I'd worry if it was balck as that would be excess fuel....and likely borewash

 

Mine was crystal clear after new turbo and engine rebuild.

Now after mapping I get a little blue on over run, I blame the std breather, I'm running 365bhp with 27psi boost.

I think the pressure in the crank is forcing the oil past the rings

 

Check the exhaust side of the turbo for oil. Sounds like seals on way out.

 

std breather sucks the shit from the kidney box into the plenum. When engine is on vacuum/overrun.

 

It's going in to get checked out next week.Hoping it's nothing too serious but needs fixed anyway so I'll be letting them deal with it.

Just noticed something last night though,the little plastic stopper on top of my dipstick is fucked and moving up and down so i'm not getting a proper reading.Too much oil wouldn't be helping would it?

 

Black smoke is an unclean combustion (blocked air filter, faulty O2 sensor etc.)

The engine is working correctly if the smoke is almost colourless on operating temp.