GTV6 3.0L

[turboalfa]

Finally finished rebuilding my 3.0L she runs like a dream untill yesterday she started to blue a bit of smoke and ive only been running it havent been thrashing it. will this go away once everything is bedded in ? ive only done approx 200km

[JOHN G]

What colour is the smoke?


Blue smoke is usually indicative of bad valve stem seals

John

[Duk]

Finally finished rebuilding my 3.0L she runs like a dream untill yesterday she started to blue a bit of smoke and ive only been running it havent been thrashing it. will this go away once everything is bedded in ? ive only done approx 200km

Have you been babying it or have you been running it in propperly by loading up the engine?
Babied engines don't push the rings against the bores and get them to bed in propperly.
Incorectly bedded rings cause glazing of the bores and excess blow by.
Excess blow by reduces the engines true prue power potential, causes oil consumption, contaminated oil (which then doesn't last as long as it should) and that leads to crap being deposted in the engine.

[tuf105]

Tend to agree with Duk.

An engine doesn't need to be "thrashed" to be bedded in but it is important to load it up and vary the rpm to ensure the rings settle in.

Blue smoke on acceleration or taking off from standstill tend to be a piston ring issue. If coasting downhill or to a stop with the throttle closed causes the blue smoke, this could be valve stem seals as John suggested.

Could be other reasons for the smoke depending on how carefully the engine was re-assembled (eg. broken ring, etc.) but I'd first try understand under what conditions the blue smoke appears before making any further judgements.

Another point I would make is the engine oil being used whilst the engine is being bedded in. Don't use oils with friction modifiers, etc. because they can upset the process. I would suggest using a simple multigrade oil and replace it and the filter after a few hundred km's as the process of bedding in generates very fine metal particles.

I hope this information is of some use.

[turboalfa]

ok guys im using some organis multi grade 20 - 50 oil for the running in..as far as loading goes. as i climb i put in 4th and just pedal all the way down whilst climbing a hill allowing the pressure and loading to begin. it only started blowing smoke after roughly 200km . and i babied it yesterday all day to see if it would change .. and now the smoke is begining to get better


Smoke only appeared when i put the foot down. not always! .only when i gave it a small amount. Im not sure if this will fix it self once its bedded in . although there are no piston rings broken etc. because we did it ourselves and have done many rebuilds before.but ive never seen the smoke before so im curious to know if it will go away. although the engine has never run the way it currently is . runs very well. amazing amount of torque and power.

[MD]

The so called rebuild , are we talkin, new pistons, rings, hone,new valve guides and valve stem seals?

[turboalfa]

yes and new crank. Valve guides stem seals , Piston rings Honed boars and new valves heads were all fresh as well.the stem seals i have are Silicone based and cost an arm and a leg and say are just bout impossible to leak.


so i have no idea. why

[MD]

Sounds right. The only difference I do is use a monograde 30 oil instead of a multigrade and run the engine in on the chassis dyno before hitting the road with it. Regrettably once the bore is glazed, they rarely recover and continue to be an oil burner.

Last thing,did you clean the crancase breather system? Could be getting excess crankcase pressure.

[turboalfa]

Ok guys blue smoke stopped today :-D and there is only black smoke as I have it running quiet rich ATM thanks guys