Smoking engine ?

[carrierbarry]

Just started my mk2 carrier after a several months laid up. She started on the button but a lot of blue smoke. I let it run for a while to get hot., but still smokes and smokes a lot when revs”. Thought maybe stuck valve or dirty old fuel. Any ideas?

[Lynn Eades]

Black smoke is fuel, Blue smoke is oil. How long have you run it? Oil is likely getting past stuck rings. Make sure there is enough oil in it and then work it a bit. A stuck valve is going to give you a dead cylinder (which btw might help it pump oil, due to no load on the rings)
I assume oil is coming from both pipes and sort of even?

[rob love]

I theorize stuck valves on these older motors may be because of the ethanol in the fuel. If it is a stuck valve, you can usually fix that right on the vehicle by first identifying which cylinder is the culprit, and then pulling that sparkplug. With a small punch you can gently tap the valve back in place, then crank the engine over and repeat until the valve moves freely again.

To identify which cylinder has the stuck valve, you can start at the exhaust pipe and with the engine running, and your hand in the exhaust stream, feel for the side that has a miss. That will narrow it down to one side. Now for the shocking part. With the engine running, you need to pull the wires one at a time and see if there is a loss of RPM, or an added roughness to the idle. If the plug is pulled and there is no change, then you have found the bad cylinder. This was often referred to as a poor mans compression test. Replace the wire and move on to the next cylinder.

These jobs are much easier with a second person.

[carrierbarry]

Thanks guys I’ll report back

[lynx42]

Originally Posted by rob love

To identify which cylinder has the stuck valve, you can start at the exhaust pipe and with the engine running, and your hand in the exhaust stream, feel for the side that has a miss. That will narrow it down to one side. Now for the shocking part. With the engine running, you need to pull the wires one at a time and see if there is a loss of RPM, or an added roughness to the idle. If the plug is pulled and there is no change, then you have found the bad cylinder. This was often referred to as a poor mans compression test. Replace the wire and move on to the next cylinder.

Instead of pulling the plug leads off why not just use a screw driver to short out the plugs one at a time. (That is if there is no insulating cap on the plug.) Just link the plug wire to the head with the shaft of the screw driver.

[Bruce Parker (RIP)]

Y'know that feeling you get when the zap goes right up to your armpit? I'm getting it now just talking about mucking with the spark...and I'm nowhere near an engine.

Careful as you are and with due regard for proper electrical insulation you just KNOW you're going to get zapped when you do stuff like this.

[Tony Smith]

Originally Posted by rob love

Now for the shocking part.

These jobs are much easier with a second person.

It's what you're NOT saying here is the important part.

If your Ignition Leads are in less than optimal condition (especially the rubber or plastic insulation that fits on to the tip of the plugs, although the leads themselves can be leaky), then pulling them off and pushing them back on while the engine is running can give you a bit of a HT shock (don't worry, while it's 40,000 volts, it's very low amperage ). That can make it difficult to hear if the engine revs have changed as you're waving your arm around shouting "Holy Mother of a Cow!"

Having a second person do the job is not always easier, as the involuntary muscular reflex of the electrical impulse can see them thump you in the side of the head, often some time later when the job is finished and you're having a

[Bruce Parker (RIP)]

Originally Posted by Tony Smith

It's what you're NOT saying here is the important part.

If your Ignition Leads are in less than optimal condition (especially the rubber or plastic insulation that fits on to the tip of the plugs, although the leads themselves can be leaky), then pulling them off and pushing them back on while the engine is running can give you a bit of a HT shock (don't worry, while it's 40,000 volts, it's very low amperage ). That can make it difficult to hear if the engine revs have changed as you're waving your arm around shouting "Holy Mother of a Cow!"

Having a second person do the job is not always easier, as the involuntary muscular reflex of the electrical impulse can see them thump you in the side of the head, often some time later when the job is finished and you're having a

I think if you have your #2 work the plugs and #2 gets the inevitable zap then a plonk on the side of your head would be the correct and expected thing your #2 would do to you. Once they got feeling back in their arm that is.

I've asked my wife to help me bleed hydraulics and hit the starter button from time to time but I'm not thinking making her my #2 go-to person for spark plug work is a good idea.

[rob love]

I meant that the other person would be to crank the engine, or to feel the exhaust for the miss. If I ever had the missus pull the plug wires and get zapped, well, I can't say for sure what would happen. I know it would not be a good thing to laugh at.



My own rule was that whomever's vehicle it was had the job at the sparkplug wires when trying to find a bad plug. When I was in the service, the old 5/4 ton chevs got a new system of shielded plugs and wires. There were a lot of failures early on, and rather than rip out everything and install 8 new wires and insulators, I would have the operator pull each wire one at a time while I felt the exhaust. I was attached to an infantry unit at the time, and some of those guys were pretty tough. But they all said ooookkkkkay the same when a spark plug wire was pulled. I would say OK if I felt a new miss and they would put the wire back in. If I could not quite discern the miss, I woudl say "do it again" and they would pull that wire out again, and say ooookkkkay? I would find the bad wire and unsulator, and have them back on the road (a little worse for wear) within a half hour vs the several hours to tailor the wire set and replace all the insulators in the shields for the plugs.

[Ron Pier]

The screwdriver to earth method is the easiest if there are no plug caps. Otherwise I disconnect all the plug caps and just rest them on the plugs. Then with some insulated pliers, lift each one in turn away from the plug. You can also hear the clicking of the spark which confirms that the lead and ignition is ok, and if the engine note changes when the cap is lifted clear, you can assume that plug is ok. Ron

[Richard Farrant]

Personally, I would approach this in a different way, remove plugs one by one noting if any particular plugs (and cylinders) are oily, this will give a positive indication as to where the problem is.

[Lynn Eades]

In the old days, getting the spark to jump a 1/4" inch gap was your lucky day, and shorting out the plug was no big deal. Any "man" could handle it!
Things have improved a bit and now the spark will jump about 3/4" (for the metric thinking, that may as well be a meter)
The idea of shorting these ignitions out with a screw driver sends a wee shiver (induced current?) up the spine of any life loving mechanic, at the preliminary thought / idea of shorting a plug out, and makes him /her (plus 20 other pronouns) wonder how much truth there is in those warning stickers about the dangers of meddling with these voodoo boxes.
Btw, for the newbies; stick the sharp end of the screwdriver hard to the head (earth point) BEFORE introducing the spark plug lead to the shank. This generates more job satisfaction, for you. If you do it the other way around, it generates job satisfaction for other people.

[RichardT10829]

Hi Barry, you say it’s smoking, is running lumpy too, or does it have a smooth idle but happens to be smoking a whole bunch ?

[carrierbarry]

Yes smooth idle, but lot of smoke.
Took it for a drive yesterday, started on the button. Lot of smoke before and after a mile drive. Seem to run better with a little bit of choke. No obvious loss of power. Fuel is about two years old, but lots and smells ok. Going to give her an oil change and clean filter. What’s the best oil and where to buy in UK.

[Lynn Eades]

Cummins Blue diesel oil because the diesel oil has more zinc that most petrol engine oils. The diesel oil is high detergent and might help to un gum your oil rings (which sounds like the problem to me?)
If not then a mono 30 grade oil high in zinc (important) The zinc has been largely removed from petrol engine oil for "enviromental" reasons.
Do some research to bolster your choice.

[Richard Farrant]

Originally Posted by Lynn Eades

Cummins Blue diesel oil because the diesel oil has more zinc that most petrol engine oils. The diesel oil is high detergent and might help to un gum your oil rings (which sounds like the problem to me?)
If not then a mono 30 grade oil high in zinc (important) The zinc has been largely removed from petrol engine oil for "enviromental" reasons.
Do some research to bolster your choice.

I would not recommend using a high detergent diesel oil in an engine of this age which is probably been running on the old style monograde with little or no detergent. You may think it will un-gum the rings, but worse than that it will release all the sediments in lower part of the engine and put them in circulating and hence cause damage to the bearings. I have been 55 years in the trade working on engines and would never use a high detergent oil in and old engine of unknown history. Just changing the oil will not get rid of the sediment.
If it had just been overhauled and clean inside, then a different matter.

[carrierbarry]

Both good answers, thanks for the help. What would you recommend Richard. New plugs, clean air filter, oil change ,,clean oil filter. And some fresh fuel.
I’m sure it’s just we’re she’s been sitting idle though the winter.
What grade of oil would you use?

[Richard Farrant]

Originally Posted by carrierbarry

Both good answers, thanks for the help. What would you recommend Richard. New plugs, clean air filter, oil change ,,clean oil filter. And some fresh fuel.
I’m sure it’s just we’re she’s been sitting idle though the winter.
What grade of oil would you use?

Hi Barry
I wouLd run the engine up and get it hot, then drain the oil. Smell the oil to see if there is any hint of petrol. If so there may be petrol leaking through the fuel pump diaphragm and into the oil and thinning it out which could be a cause of the smoke. The specified oil for Carriers by British army was SAE 30 and I would use one of the Classic 30 oils which you often find stocked in local motor factors.
I did suggest in an earlier post to take the plugs out one at a time to see if any particular ones were oily as that could indicate a problem withiN that cylinder.

[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.