Good day everybody

I was told by some observers that my truck burns oil and has blue smoke. I am not sure if it is true. Here are the signs:

1. It runs like a clock and I don't see smoke consistently. It comes and goes.
2. lately when I start the truck in the morning there is a big bank and a puf of black some comes out of exhaust.
3. Engine has the same power as ever and I do not feel any unusual sound or performance issue.
4. The fuel (gas) quality here is very dodgy and I might have put bad fuel with oil in it last time. In fact I recal runing out of fuel and having to borrow an empty 4 liter can of oil to get some gas for the truck (as usual looking back I see that that was stupid).

How can I check if I am buring oil or not?
I checked on internet I found a video by somebody named scotty kilmer on youtube that says change your pcv valve and problem is solved. I don;t think a 85 santana especial series 3 has any pcv valve. Does it have anything similar that could be changed?

best regards and thanks in advance

Is it diesel or petrol?

I would adjust your mirror so that it's looking at the exhaust exit. If it smokes when accelerating then that would be bore or piston ring issues, if it smokes on the overrun then that's usually valve guides or seals. Generally!!

If it's a diesel and you don't have a brake servo then it's less likely that you'll get smoking on the overrun as you don't have the same manifold pressure that you would with a butterfly in the inlet stream.

You could try cleaning all of the breathers (the one on the rocker cover and the oil filler), soak them in petrol for a while then allow to dry.

Ah, just noticed you've got 2.25 petrol in your footer!

Check to see when (or if) you get blue smoke, when accelerating hard or when on the overrun.

Black smoke would be overfuelling I guess, is the air filter clean? Maybe time for a carb overhaul?! Is the ignition timing correct?

I'm sure somebody that knows more than me will be along soon!!

Get someone to drive it and follow them. See whether it is worse accelerating, cruising or on the overun, all are diferent causes. Look at the colour, black or grey.
Grey is oil, grey crusing is worn engine, (or oil in fuel if its contaminated), grey overun is worn valve seals or guides, black is fuel. Black cruise is rich, black acceleration is rich but on acclerator pump/circuit, depends on carb.
Go for a long run withthe engine hot. Wipe the rear panel, if its burning a lot of oil there will be oil spots all over it, if its fuel it will be sooty.

Thank you all for your help.
I put a 5 liter container of fuel in the truck and headed out of town in a straight line to empty the tank (most goofy way to remove the possible oil). I drove till the truck huffed and puffed and came to stop. Then I put the 5 liter int he tank and drove to a petrol station and filled the tank with highest grade of petro I could find. I drove around for another 50 km and I am glad to say I do not see any signs of bad odor or smoke. It seems like oil in the little container of emergency petrol I had used 2 weeks ago was casuing the smoke and puffing. Hopefully high grade petrol will wash the system (or I am told, otherwise I have wasted a lot of money).
Lesson learned is that never let your tank be emptied and never use a oil can to get petrol in your tank.
I am happy to know the love of my life does not need an engine job
Thanks for your suggestions.