Smoking engine ?

[Ron Pier]

I concur with Richard regarding the detergent oil. Ron

[carrierbarry]

I checked plugs, no oil. But running a bit rich.
Took leads off one at a time ,each time engine missed.

Think I’ll change oil.

[Lynn Eades]

Richard has a good point about using a diesel oil in an older engine. I dont know the details of your engine and that's why I suggested you do some research. I run a "Total" brand diesel oil "Rubia "mono grade 30 which is designed for older engines. As it happens, I don't run a mechanical pump because I have seen some problems with old diaphragms and modern fuel, that have lead to oil dilution and run bearings. I also run a full flow oil filter in my cooler line.
The benefit of the high detergent oil is that once the engine is clean it will stay clean. I have run this oil from a major rebuild.
The Cummins Blue recommendation came from a study on the Ford Barn Forum and was the result of a study of various oils and their contents of various additive packages. The problem with modern (mainstream) petrol oils is they lack enough zinc to protect the cam and followers from premature failure.
Richard's "Classic 30" is good advice (not that I am judging him in any way) The "classic" bit covers the zinc issue. The straight 30 grade recommendation is about the greater ability of the mono grade to transfer heat. I too am an "A" grade mechanic of 50 years in the game, but I have probably done less engine work than him.

[Lynn Eades]

Barry, I suspect you have stuck oil rings. My reasoning is that you have 8 cylinders that are firing and otherwise working. You just have excess blue smoke? (that's a question)
Here's a statement pulled from the net.

Stuck piston rings are caused by carbon deposits in the ring grooves. Hard carbon, a result of poor fuel combustion, virtually cements the rings into the grooves. In the past, the only way to free up stuck piston rings so they seal properly again, was to overhaul the engine.

I see a couple of things that you might investigate:
FTC Decarboniser. This is a pack that comes with a flushing oil.
Marvel Mistery oil.

I've never seen or used either, and there are probably more options.

Assuming you have no other mechanical problems (like broken oil rings?) and you do not want to rebuild your engine, then continuing to use your engine in the same way will only cause the problem to continue or get worse?
I assume that to try and fix this then you need to take on board a change of direction? (an attempt to pull it back from the brink, so to speak)
The reason I suggested you "work" the engine was to try and free the rings. An oil ring is supposed to scrape the oil down the bore and ride the oil going up. therefore it needs to be free to move in the groove. I suspect they (the oil rings) are stuck in their grooves and that your compression rings are still free. If you had one stuck (or broken?) then the engine would probably puff rather than put out a steady flow of smoke?
One of the above additives might fix the problem by freeing your rings, but you will probably need to flush your engine anyhow, because by chemically removing carbon at the rings, will no doubt free up the crap that Richard is talking of.
Having gone through this process (which is not guaranteed) then you have to decide what oil to use. I would then use a high detergent oil, if it were mine, to try and keep the rings clean.

We can all make our comments, but non of us has skin in the game. Only you.
Good luck with what ever you decide.

[carrierbarry]

The blue smoke is even out of both exhaust pipes. Surely not all rings/valves stuck..?

[charlie fitton]

Disconnect, or block off the crankcase vent and see if it changes anything after a few minutes running.

[RichardT10829]

No, but in order for both sides to be pushing out the blue stuff, both banks on the engine would need to have the same issue.

*We know the engine idles ok, runs ok too.

* We know both halves of the engine are affected.


If it were myself, I would consider the following….it’s only my opinion and I don’t wish to add to the can of worms that tends to appear on engine issue threads.

1) start engine up, pull the oil filler cap off, are you getting strong puffs of smoke coming out ? What is the state of the hydrovent ? What’s your oil pressure like ? Too much is also bad.

2) Compression test every pot / bore on both banks, is each bore the same ? What is the compression ? Check every plug whilst you are at it.

3) check oil and coolant for cross contamination.

4) get engine good an hot then dump the oil, flush the engine out.

5) drain the old fuel and put some fresh good stuff in.


List generated in no particular order. But will tighten up your search a bit.

Stuck rings / valves are popular, especially if the machine has been sat in a damp location for quite a while.

[Jesse Browning]

A PCV valve that is stuck open, or has been bypassed can suck up oil in some engines and make smoke.