240dkw

Engine Burning Oil

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    I have spent the last few days trying to solve my engine problem with no luck so far. The motor has been running for a week with oil pressure that would get higher with engine RPM. I did a search and figured it was the pressure relief in the oil pump. I took the relief out of the oil pump and everything looked good. After reinstalling it, I had the same problem. I then installed a gauge in the oil sensor port and ran it for a while. It started to run at a nice 60 psi. And I thought I had fixed it but at the same time it started to run really rough. And of course really started smoking out the exhaust. I pulled the plugs and all six looked nasty. Black and oily. The fact that all of the plugs are dirty is odd. I pulled the PCV hose off and ran it for a while to see if any oil was coming from there and back to the intake but it was good.I then did a compression test with the following results.
    #1 - 158
    #2 - 159
    #3 - 160
    #4 - 160
    #5 - 158
    #6 - 157
    I then did a leak down test
    #1 - 100/92
    #2 - 100/94
    #3 - 100/92
    #4 -100/94
    #5 - 100/81
    #6 - 100/80
    I can hear the air leaking somewhere on both 5 and 6
    So I pulled the head off.

    There is a fair bit of oily, black soot inside the cylinders. Everything looks good on the head gasket, so I have not found anything yet. As it is in all 6 cylinders I do not understand where it is coming from.
    Is it possible for the oil to be passing by the rings and still get that good of compression results?
    What would the cylinders look like if it was a coolant leak instead of oil?
     

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    IMGP2086.jpg

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    25 minutes ago, 240dkw said:

    The motor has been running for a week with oil pressure that would get higher with engine RPM.

     It started to run at a nice 60 psi. And I thought I had fixed it but at the same time it started to run really rough. And of course really started smoking out the exhaust. I pulled the plugs and all six looked nasty.


    Is it possible for the oil to be passing by the rings and still get that good of compression results?


    What would the cylinders look like if it was a coolant leak instead of oil?

    You didn't give any "higher" numbers so the 60 psi that follows has no point of reference.  

    It is possible for oil to pass the rings and still get good compression.  The oil scraper rings and the compression are two different sets of rings, with different functions.

    Not really clear what the "problem" is.  High oil pressure or running rough or smoking.  Seems like you're assuming that high oil pressure is going to cause problems.

    Reminds me of all of the effort I spent trying to solve a "problem" on an old muscle car in high school.  In the end it just need a new set of plugs and points.  No offense, you described several things happening but they might not be connected.

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    Those pics don't really look like an oil burner to me, unless its only just started.
    It just looks like it's been running too rich.

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    It would get over 80 psi when up around 5000 RPM, it followed the engine speed 40-45 at idle and up to 80+. The "problem is a rather large amount of smoke coming out the pipe. I do believe the high oil pressure caused something to happen.

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    It did just start to happen, it has only ran in the garage since it started to smoke.

    Edited by 240dkw

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    Does it smoke at idle or only at higher revs?
    What colour smoke?
    The idle relief should do its job before 80 psi.

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    It smokes at idle and a greater amount(a lot) of smoke when reved up. The odd thing is that the higher oil pressure disappeared at the same time it started to smoke. Almost like something let loose. The smoke is blue.

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    1 hour ago, 240dkw said:

    It smokes at idle and a greater amount(a lot) of smoke when reved up. The odd thing is that the higher oil pressure disappeared at the same time it started to smoke. Almost like something let loose. The smoke is blue.

    Can you here rattling from the engine? If so probably the valve guides, if not probably the piston rings 

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    1 hour ago, 240dkw said:

    It smokes at idle and a greater amount(a lot) of smoke when reved up. The odd thing is that the higher oil pressure disappeared at the same time it started to smoke. Almost like something let loose. The smoke is blue.

    Here's an issue some people have, fairly inexpensive to fix and see if it works bad valve stems cause high oil pressure and smoke issues.

     

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    Valve stem seals and/or guides have no effect on oil pressure. Can have impact on consumption, but not on pressure.

    So just to make sure I understand the issue.... Car had been running great. No problems. Then one day, all of a sudden your oil pressure started running way higher than it used to, and you started blowing blue smoke?

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    Valve stem seals and/or guides have no effect on oil pressure. Can have impact on consumption, but not on pressure.
    So just to make sure I understand the issue.... Car had been running great. No problems. Then one day, all of a sudden your oil pressure started running way higher than it used to, and you started blowing blue smoke?
    I read it as: Oil pressure was observed to be "high", relief valve was removed or Modified and then it started smoking.

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    Captain: Sorry for the confusion, jonbill is correct. It has been running great, but with high oil pressure for about 100 miles or so. Then I checked the relief valve, all good with no modification. Started it up again and still had the problem.. Shut it down, installed gauge started it up and pressure was good at 61 psi.
    Shut it down and installed a new pressure sensor I had. Start it up and reading was good, but started running rough. Looked in rear view mirror and large cloud of blue smoke. This all happened in the space of 15 min. The two problems might not be connected as Zed Head eluded to but it seems to me that they are connected.

    Edited by 240dkw

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    Lets start with causes of high pressure

    Problem with the oil relief

    Bearing clearances

    Excessive pump output

    What is the engine history? Have you ever run any oil flush through it? If you haven't,  don't!

    My first concern would be junk building up in the bearings driving up oil pressure.  Oil relief could also be a problem

    • Like 1

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    Perhaps:

    There was an incident in the engine that blocked something that drove oil pressure up.

    That caused something else to deliver oil into the combustion Chambers, even after the original high pressure incident is resolved.

     

    I can't imagine how high oil pressure could damage valve stem seals or oil control rings.

    I can imagine high oil pressure might damaging the head gasket and leak oil into a couple of Chambers, but hard to think how that might make all cylinders equally sooty.

     

     

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    20 minutes ago, jonbill said:

     

     

    I can't imagine how high oil pressure could damage valve stem seals or oil control rings.

    I can imagine high oil pressure might damaging the head gasket and leak oil into a couple of Chambers, but hard to think how that might make all cylinders equally sooty.

     

     

    The head gasket idea is what drove me to take the head off, but I can not find anything wrong with it. 
    It has about 600 miles on a complete rebuild and has been running awesome with no problems until this one.

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    39 minutes ago, 240dkw said:

    Captain: Sorry for the confusion, jonbill is correct. It has been running great, but with high oil pressure for about 100 miles or so. Then I checked the relief valve, all good with no modification. Started it up again and still had the problem.. Shut it down, installed gauge started it up and pressure was good at 61 psi.

    Shut it down and installed a new pressure sensor I had. Start it up and reading was good

    Could be that the guage in the dash wasn't reading right.  It seems possible that the oil pressure was never really too high.  When you installed the gauge on the engine block you disconnected the dash gauge.

    The high oil pressure reading might be a coincidental distraction from the real problem.

    • Like 1

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    If the engine is fresh, then high oil pressure wouldn't concern me too much. I rebuilt a chevy that did the same thing because the mains were on the tight side. I dont know how too high is a problem unless it gets to 100 psi. Then the oil filter can be at risk. What weight oil were you running?

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    4 hours ago, Captain Obvious said:

    Valve stem seals and/or guides have no effect on oil pressure. Can have impact on consumption, but not on pressure.

    So just to make sure I understand the issue.... Car had been running great. No problems. Then one day, all of a sudden your oil pressure started running way higher than it used to, and you started blowing blue smoke?

    Only reason I suggested those two is because he said all the spark plugs are fouled with oil... those would be the most lightly culprits for that to happen 

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    There Is a possibility that you could be running way too rich? But you would be able to smell that, it can cause black grime on the plugs and blue smoke but pretty improbable that, that is the reason.

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    14 hours ago, 240dkw said:

    It would get over 80 psi when up around 5000 RPM, it followed the engine speed 40-45 at idle and up to 80+. The "problem is a rather large amount of smoke coming out the pipe. I do believe the high oil pressure caused something to happen.

    It might help to get in to the basics of the engine and its lubrication system.  There is no "pressure" that would force oil in to the combustion area.  High oil pressure might lead to high oil volume, flooding the top of the cylinder head, but there is plenty of room for the oil to flow back to the crankcase.  You could have excess oil flowing through the main bearings, splashing up n to the cylinder walls as it gets thrown off, but the oil scrapers would have to be seriously overwhelmed to have that oil get ni to the combustion area.

    In short, oil pressure and smoke from the exhaust are not connected.  It's actually more likely to see low oil pressure and smoking on a worn engine, with worn valve seals, than on a low mileage engine with high pressure and good valve seals.

    The two problems could be coincidental but there's probably no cause-effect relationship. 

    image.png

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    3 hours ago, Zed Head said:

    Could be that the guage in the dash wasn't reading right.  It seems possible that the oil pressure was never really too high.  When you installed the gauge on the engine block you disconnected the dash gauge.

    The high oil pressure reading might be a coincidental distraction from the real problem.

    I did start there as well, I used a variable resistor and walked the gauge up and down the scale and it is working correctly a few days before this happened. 
    I do not disagree with you as a coincidental problem. 

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      You describe the black soot in the cylinders as oily and yet I don't see the oil sheen in the pics. The pics look like sooty cylinders from running too rich. Stick your finger in the tailpipe and take a sample. Is it reasonably dry black soot or is it wet, oily black soot? I'm leaning toward no oil pressure problem (new engine) and it's running extremely rich. Also the fact that it started running lousy in short order rather than gradually getting worse, like fouling plugs do, seems like this is a mixture problem. That said, the oil pressure is something I'd keep an eye on.

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    16 hours ago, 240dkw said:

    #1 - 158
    #2 - 159
    #3 - 160
    #4 - 160
    #5 - 158
    #6 - 157

    I then did a leak down test
    #1 - 100/92
    #2 - 100/94
    #3 - 100/92
    #4 -100/94
    #5 - 100/81
    #6 - 100/80
    I can hear the air leaking somewhere on both 5 and 6
    So I pulled the head off.

    So, "now what?" is the question.  

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    how about this oil pressure a non issue, sudden consumption on freshly rebuilt engine from a valve stem seal that has popped off?

    Did we try the high vacuum (down shift while throttle closed) run then suddenly get on it for a cloud of blue smoke after sucking in oil during high vacuum?

    I would be tempted to pull the valve springs off and at least check to make sure they are all seated.

    Edited by Dave WM

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