After an eventful two days I have new 9.0:1 cylinders and pistons in my 2cv, at the end of the second day I also had them in my 2cv, but due to some rather silly mistakes I also managed to fill my exhaust with engine oil.

Having rebuilt it again correctly it runs beautifully, however it does on occasion do its dragon impression and lay down a rather impressive smoke screen to induce those behind to put on their fogs. How can I tell whether its fresh engine oil burning, or the oil that still resides in the exhaust?

Does anyone know roughly how long it takes to burn an oil lining out of an exhaust (van style side pipe)?

How do people suggest running bits in?

Many thanks.

It's a bit of a faf but perhaps remove the heat exchangers and try running it-if it doesn't smoke then I guess you could assume it's in the exhaust.

I had a Dispatch HDI van at work once with an exhaust full of oil-it took about 5 hours for it to clear!!

How??

terpineol,
I had this problem recently, where the owner had poured a 'cupful or so of oil' into the crossbox to preserve it whilst he had the car apart.
At first, I couldn't understand where the smokescreen was coming from when the car was driven hard.
Iirc, it only took about 10 miles to burn it all off.
There was hardly any smoke when just pottering along, but when the pedal was to the floor so that the exhaust was warmed up properly, it was quite entertaining...

Have you had a look at STP's site for a quick method of breaking in new pistons and barrels?
Here's what he recommends and it's what I've used on engines which I've rebuilt recently...

"Now your must break in your engine on a road or highway:
This can easily be done following this procedure.
Look for a road that allow you to do the following: For fast and safe break in of pistons, rings and cylinder we recommend to accelerate your car with floored accelerator from 40 Km/hr in the greatest gear (Fourth or fifth gear) to almost maximum speed the engine will reach.
Never force the engine to rev up more than it's willing to do!
Reaching the speed of around 90/100 Km/H remove your foot and let the car (without disengaging the gear or clutch) decelerate and slow down to approx. 40 Km/hr.
Then reaccelerate with flooring your accelerator to repeat this.
Do that 15 times and drive 50 Km “normally”.
When accomplished your engine is really break in to 80%. The last 20% of engine break in is done during daily driving but don’t force your engine to RPM levels that it will not reach or too high RPM or to high load with a long gear during hills climbing!"

ken.

Many thanks for the replies thus far.

I took it for a spin last night with a smoke watcher in the passenger seat, the smoke production he thinks has declined but it was hard to tell in the dark.

On checking my oil thismorning last nights ~5mile drive appears to have used some oil, how long will it take for the oil control ring to bed in, and while it does so how much oil consumption should be expected?

Many thanks again.

Did you fit new valve stems seals when you had the heads off.

Not on these heads, the ones I took off had new seals not long ago so they should (and were before the piston change) be fine.

I did after snapping the studs for the exhaust manifold put some other heads on which turned out to have no stem seals, hence filling the exhaust with oil.

I would have changed the seals but was unable to track down a suitable valve spring compressor. If anyone can recommend one suited to my diminutive budget it would be splendid.

I took it for a spin this-morning (with the old working heads, as installed yesterday) and it seems almost smoke free, so hopefully it was the exhaust (I parked it pointing nose uphill in the hope it would all run out the end)