Just had new saph serviced with new oil filter etc etc. new plugs (the right ones)

Compression test done showing between 150-160 on all cylinders.

Boost raised to 20psi from 15psi and a new chip.

car has new looking t34 with no play in shaft atall. rs 500 cooler and greens.

Now it dont smoke on tick over atall. And if driving normally it does not smoke.

however as soon as i bring it onto boost above 10 psi i get clouds of bluey blackey smoke until its hot then it seems to calm down but i just dont know anymore.

It had some real shitty oil in it before and we all thought it might just be sitting in exhaust but ive drove it for a while now and its still doing it.

The one thing i can think of is its not got an uprated breather system, could this be it.

Is there anything i can try before i spend £150 on a better breather.

Any help would be great, everyones saying just drive it its fine but i dont like it the way it is and i could never put up with it.

Cheers

Rob

 

black smokes "normally" indicates fuel related

blue "normally" indicates oil

how old is the engine, new build or old?

if its old, i'd bet its worn oil rings on pistons. it would make sense as when old the pistons have expanded due to heat; therefore oil and pass by the worn oil rings, when the motor gets hot, the rings/ pistons expand and seal better

the only other mechanical thing it could be is worn valve stem seals or valve guides, a good way to see if its stem seals/ guides is to overrun down a big hill; then at the bottom give it a boot - if a big puff of blue smoke appears, then "more tha likely" its likely to be guides or stem seals.

to be fair it could well be oil sitting in the mainfold or it may well need a decent breather, but in my experience i doubt it.

has it been set up; have you had the CO% set correctly? what's the AFR reading? what chip is it? it could be a rubbish chip which just overfuels or the wrong chip for your spec

Matt

 

When i had my turbo changed due to oil seals, the oil took absolutely ages to clear from the elbow and exhaust. I thought my new turbo was fucked (OVER TWO WEEKS) until it had all stopped, and that was about 10k trouble and smoke free running ago with no more smoke

 

Thanks for the replys guys.

No its not a new build its an old engine that looks like its been rebuilt in the past, My tuner also reckons its valve guides.

i just cant get to grips with the way it drives fine with no smoke until youre on boost!

I took the pipe from the oil breather to the manifold off last night and there is oil in there.

I took out the one way valve whingy that is in the plenum and blew through it and oil came out of it.

Theres not supposed to be oil in there is there?

Im told i can block that pipe off at both ends so im ging to try that.

 

also if it was piston rings would the compression not be low?

 

it maybe a problem with the turbo then if its only on boost - has it been set up? what the AFR?

if its worn piston rings then yes it will show in a comp test, but if its worn oil rings then no they do not always show on a comp test

there's a difference between oil & piston rings

 

This is exactly whats happening with mine Matt!
So you'd say guides or stem oil seals?

 

Hello mate; yeah its normally a good indication its either guides or stem seals - but it could be other things too

its a bit of a ball ache to do, but when its done its done