1986 928s Excessive oil in intake / burning oil
#16
Rennlist Member
have you checked the oil quantity? sound to me like you may have a bad FPR or damper and hydro locked it last winter. you may have excess volume of oil in the crack case as it may be diluted with fuel. also at idle you may be extremely rich causing excess smoke not just due to oil but also the added fuel from the leaking diaphragm on the regulator/damper.
#17
Rennlist Member
It could only be rings doing this, i think we have narrowed that much down, and a leakdown would only tell me the same thing as compression when it comes to rings, can we agree on that much?
I guess I seem flippant or dismissive based on the tone of your response -
I guess the pcv system really is so poor on the 928 that bad rings would do this
I've never seen bad rings blow oil into the intake via pcv.
Again, please don't take me the wrong way. Its hard to get tone and inflection across in text.
I guess I seem flippant or dismissive based on the tone of your response -
I guess the pcv system really is so poor on the 928 that bad rings would do this
I've never seen bad rings blow oil into the intake via pcv.
Again, please don't take me the wrong way. Its hard to get tone and inflection across in text.
I like to help those with issues where I can as others did for me in years gone by when I knew squat about these cars. After 16 plus years of ownership I know a bit more than I did but there is still an awful lot I do not know. Those of us with some knowledge like to help filter the problem so that our really knowledgeable chaps can jump in when the radar clutter has been sorted.
The breather systems on the 32Vmotors have been the subject of extensive debate and development. I do not think of your model year as being particularly problematic so at the moment I suspect you have a relatively serious issue whatever it may be- proving what it is - that is another matter altogether.
Be assured I do not take anything personally- I will discuss anything with anybody but I do not get into personal internet pissing matches with anyone- I offer the best advice I can and after that it is up to the individual whether he choses to act on it or ignore it- no offence ever taken. Intelligent debate I welcome any time.
#18
Rennlist Member
Never heard of that one before - an engine cranking but not firing, no heat being put into the motor, no real load on the motor and it seizes? The oil pump is positive displacement so no issue with the mains/big ends as long as ther eis oil in the sump I would think. I suppose if the splash lubrication at cranking speed is not working correctly the rings could ultimately lose oil on the cylinder wall and possibly do no good but seize? Interesting to know what other listers think about that one.
#19
Former Vendor
You probably left out the check valve in the filler neck that goes in the hose to the intake. Without this valve you have a direct 1/2" tube from the crankcase to the intake.
Combine that with a bad cylinder that is making excessive crankcase pressure and you are essentially pouring oil directly into the crankcase.
Beyond that, it sounds like you would be happier with a Chevy. Sell the 928 and move on to what you want.
Combine that with a bad cylinder that is making excessive crankcase pressure and you are essentially pouring oil directly into the crankcase.
Beyond that, it sounds like you would be happier with a Chevy. Sell the 928 and move on to what you want.
#20
Never heard of that one before - an engine cranking but not firing, no heat being put into the motor, no real load on the motor and it seizes? The oil pump is positive displacement so no issue with the mains/big ends as long as ther eis oil in the sump I would think. I suppose if the splash lubrication at cranking speed is not working correctly the rings could ultimately lose oil on the cylinder wall and possibly do no good but seize? Interesting to know what other listers think about that one.
I fully agree nothing whatsoever about this makes any sense at all. I know what a dead cylinder on this motor sounds and feels like because i forgot to attach a spark plug lead while diagnosing the issue and its definitely firing on all cylinders.
#21
Rennlist Member
Just a note on the Good Idle statement, I've see many runners that are only running on 7 of 8 cyl and the owner never even knew it
You can also have good compression rings and a bad/broken Oil Ring, have you considered that?
The 928 engine is mostly bullet proof as far as Block and rings go, rarely see one smoking due to bad rings/ block issues.
However as you said you knew what your did, now we need to find out which cylinder(s) and if that is really what is going on here or is it incorrectly assembled PCV, as Fred said the S3 usually manages it better than the later 32v engines.
Keep us posted,,
Dave K
You can also have good compression rings and a bad/broken Oil Ring, have you considered that?
The 928 engine is mostly bullet proof as far as Block and rings go, rarely see one smoking due to bad rings/ block issues.
However as you said you knew what your did, now we need to find out which cylinder(s) and if that is really what is going on here or is it incorrectly assembled PCV, as Fred said the S3 usually manages it better than the later 32v engines.
Keep us posted,,
Dave K
#22
You probably left out the check valve in the filler neck that goes in the hose to the intake. Without this valve you have a direct 1/2" tube from the crankcase to the intake.
Combine that with a bad cylinder that is making excessive crankcase pressure and you are essentially pouring oil directly into the crankcase.
Beyond that, it sounds like you would be happier with a Chevy. Sell the 928 and move on to what you want.
Combine that with a bad cylinder that is making excessive crankcase pressure and you are essentially pouring oil directly into the crankcase.
Beyond that, it sounds like you would be happier with a Chevy. Sell the 928 and move on to what you want.
I take offense to your comment about being better suited to a Chevy. I won't speak further on that comment because I'll get rude if I do.
#23
Rennlist Member
You probably left out the check valve in the filler neck that goes in the hose to the intake. Without this valve you have a direct 1/2" tube from the crankcase to the intake.
Combine that with a bad cylinder that is making excessive crankcase pressure and you are essentially pouring oil directly into the crankcase.
Beyond that, it sounds like you would be happier with a Chevy. Sell the 928 and move on to what you want.
Combine that with a bad cylinder that is making excessive crankcase pressure and you are essentially pouring oil directly into the crankcase.
Beyond that, it sounds like you would be happier with a Chevy. Sell the 928 and move on to what you want.
#24
Rennlist Member
If it was hydro locked with fuel it will not turn over even if being dragged. setting all winter will allow the fuel to seep past the rings and into the crankcase overfilling the oil. Cant imagine freeze/thaw effecting anything other than water as oil will stay liquid well into negative numbers.
have you check the oil level?
have you check the oil level?
#26
have you checked the oil quantity? sound to me like you may have a bad FPR or damper and hydro locked it last winter. you may have excess volume of oil in the crack case as it may be diluted with fuel. also at idle you may be extremely rich causing excess smoke not just due to oil but also the added fuel from the leaking diaphragm on the regulator/damper.
#27
Yes but there is no way I am going to reach that without pulling the intake again, my hands are thin but they aren't that thin. Can the oil neck be removed without pulling the intake?
#28
If it was hydro locked with fuel it will not turn over even if being dragged. setting all winter will allow the fuel to seep past the rings and into the crankcase overfilling the oil. Cant imagine freeze/thaw effecting anything other than water as oil will stay liquid well into negative numbers.
have you check the oil level?
have you check the oil level?
#29
Rennlist Member
EDIT: and don't even bother w/ the Dipstick "O" rings, won't cause your issue, unless oils is coming OUT of them then replace them
#30
Thinking about it now, I never removed the line that is listed as having the pcv valve in it. It could be that there was never a valve present and now that all vacuum leaks are sealed it is pulling more vacuum than normal and only showing the issue now. I don't know and cant say without pulling it completely apart again