Smoke between white and blue by escape in Renault 19

Hello, the vehicle is emitting white to blue smoke when the RPMs exceed 2500 (note: it doesn't do this at idle).
- The valve guides and seals were replaced approximately six months ago.
- The engine was completely rebuilt a year ago.
- There is no water in the crankcase or oil in the coolant reservoir.
- There are 150 psi in each cylinder.

Thank you in advance.

Hi Javielito86, it would be helpful if you could tell us if it's a diesel engine, if the smoke smells like burnt oil or diesel, if it only happens when the engine is hot or also when it's cold... if it's gasoline, if any spark plugs are fouled, which might suggest a broken oil ring... if the valves were replaced in addition to the guides, if it's consuming oil or more fuel than normal... it will be easier to give you an opinion. Regards!

Hi everyone, Javielito86. Based on the compression (150 psi), I imagine it must be gasoline. It would be good to know if the problem appeared immediately after the engine repair or if it developed gradually? Also, thinking about it, I saw a case where a leaking injector contaminated the oil with gasoline, diluting it (losing viscosity) and allowing it into the combustion chamber after approximately 2500 RPM or when the engine was under load. This assumes the smoke smells like oil, which is important. If it doesn't smell like oil, it could be coolant... the glycol and additives it contains produce smoke like the one described. Finally, and much more rarely, if there's no coolant or oil consumption and white-blue smoke persists... I've very rarely seen brake fluid leak into the brake booster due to a broken brake master cylinder seal, and from there into the engine. Brake fluid is also glycol- or alcohol-based with additives, so when it burns, it can also cause a white-blue tint in the exhaust gases, but it's extremely rare, and you should notice fluid consumption and problems in the brake system.
If the problem is oil consumption in the engine, you should notice it on the spark plugs; the residue on each one helps identify if the oil is getting into one or all of the engine cylinders. Oil consumption with good compression and smoke... it could be what Ismael said: a broken piston ring or oil ring, or an incorrect or reversed oil scraper ring (the second one upside down). When it's due to the valve guides or seals, it smokes more when decelerating and pulling away from a stoplight. Let us know how it goes... Well, I won't bother you anymore... Greetings to all.

Sorry for the delay, I haven't been able to access the page; it kept giving me an error.

ismael53, the vehicle is gasoline-powered, and oil is appearing on all four spark plugs. It consumes oil but not gasoline. The valve guides, valves, and seals have been replaced.

fiat147, what you mentioned about "oil consumption, with good compression, smoke..." could be what ismael said: a broken piston ring or oil ring, or an incorrect or inverted oil scraper ring (the second one is reversed). That's most likely what's happening. We're already looking for the rings to replace them. Thanks for the help; I'll let you know later.

The problem is that it's burning oil, which causes it to emit blue smoke, and the exhaust fumes can even have a bad smell...
I hope this helps.