My son recently bought an Mi16 (think BX16V) with 120K klms on the speedo that had the engine "rebuilt" at 88,000 (and twice since) and when we drove it home, almost 400 klms away, it managed to empty the sump via the exhaust pipe.
To make a long story short, we have now managed to have a look at it and when the intake plenum was removed, there was close to 5mm of oil sitting on the intake valve in number 1 cylinder.
Logic says it needs new valve stem seals which weren't all that good a fit when we removed them, but instinct says if this car was "rebuilt" at 88K, why? If it's been done twice since (riings, pistons and liners) again why?
What else could be causing 5 litres of oil to burn in 400 klms? Before anyone suggests that this amount is impossible and it may be leaking, it had fully choked a new spark plug up with oil and baked it solid in the guts of the plug in that one trip!! Also, it has sat on a clean concrete floor since we got it home and refilled the crankcase and hasn't leaked a drop; any ideas anyone?????
Alan S
Oil guzzling.
Moderator: RichardW
Alan if I understand you correctly when you took the plenum chamber off, no 1 inlet valves were shut and the oil deposit was sitting on the back of the shut valves.
5mm of oil is an enormous amount there and isn't the result of blowby and ventilation into the induction system. In any event I think the plenum arrangement is that the pipes curl downward so I would expect to find a huge amount in the bottom as well.
When I hear of oil consumption experience has taught me to expect the worse - ie rings/pistons/bores - but tired engines with worn rings etc generally have considerable blowby and leak - especially if they are using this quantity.
I have never dismantled one of these engines but do wonder if you have a casting/machining defect and one of the valve spring seats has been machined too deep in the head or has struck a flaw and oil is simply leaking down into the valve port. Not a common defect I know but the problems you are having aren't common either.
Jeremy
5mm of oil is an enormous amount there and isn't the result of blowby and ventilation into the induction system. In any event I think the plenum arrangement is that the pipes curl downward so I would expect to find a huge amount in the bottom as well.
When I hear of oil consumption experience has taught me to expect the worse - ie rings/pistons/bores - but tired engines with worn rings etc generally have considerable blowby and leak - especially if they are using this quantity.
I have never dismantled one of these engines but do wonder if you have a casting/machining defect and one of the valve spring seats has been machined too deep in the head or has struck a flaw and oil is simply leaking down into the valve port. Not a common defect I know but the problems you are having aren't common either.
Jeremy
Hi Alans..
Could be that a piston is acting as an oil pump? rings wrongly fitted? wrong type of rings fitted? wrong size? rings broken? ring gaps all lined up? Liners poorly fitted, oversized or oval? Plus the sump may be pressuring a bit due to breather restriction somewhere? Head gasket badly fitted? or casting has a groove or crack in it somewhere that expands when hot?
Any pressurised oil mist appear when you take the oil filler cap off? Be carefull, I once had the oil mist explode in the sump and the dipstick missed me and made a huge dent in the bonnet!! The cause for that turned out to be a hole in a piston.. (old ford consul) [:I]
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Could be that a piston is acting as an oil pump? rings wrongly fitted? wrong type of rings fitted? wrong size? rings broken? ring gaps all lined up? Liners poorly fitted, oversized or oval? Plus the sump may be pressuring a bit due to breather restriction somewhere? Head gasket badly fitted? or casting has a groove or crack in it somewhere that expands when hot?
Any pressurised oil mist appear when you take the oil filler cap off? Be carefull, I once had the oil mist explode in the sump and the dipstick missed me and made a huge dent in the bonnet!! The cause for that turned out to be a hole in a piston.. (old ford consul) [:I]
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I agree James that this could be a source of excessive oil consumption but how does the stuff end up in a pool on the back of No 1 inlet valves. If the breather was getting that much they would all be affected and I'd also expect the engineto be covered in the stuff and leave a trail on the ground.
Interesting puzzle!
Jeremy
Interesting puzzle!
Jeremy
Hi Jeremy.. Now that I dont know..[:I] But Alans seems to have ruled out it coming down the valve guides, other than that or a cracked casting, I don't have a clue.
No one had replied when I wrote my posting and if nothing else my comments would have kept it up the list. (as does this one) [;)] [:D] lol..
No one had replied when I wrote my posting and if nothing else my comments would have kept it up the list. (as does this one) [;)] [:D] lol..
I advised him to buy this car as I reckoned it was a challemge, a nice car for a young fellow to own and stand a chance of picking a $$ up in the process.
There is no sign of oil even in the intake plenum; the valves is it.
Looking at the engine, valve #1 @ the RHS is swimming in it (5mm) #2 is wet, #3 is moist, #4 almost dry, the rest normal.
So far, the beat theory we've come up with is that the valve stem seal was fitted too loosely and the outer portion of the hydraulic cam follower is acting like a piston and compressing the oil between it and the head and the oil is then taking the least line of resistence down past the loose fitting seal and down the valve stem, but is it logical to expect a seal such as this to withstand that kind of pressure or is there a developed fault that is allowing too much oil to be trapped in there (oil return or a relief of some sort) that may be blocked and creating a situation where the oil can be there in such a volume that it is getting compressed? If this were to be the case, it may explain why they have been pulling this engine apart for the past 40,000 klms without success, but to me, I think this is grasping at straws. I intend looking at it in a bit more detail later in the day. I'm trying if at all possible to do this without removing the head.
Has anyone else ever done valve stem seals on one of these engines without removing the head incidentally? That was another challenge; designing and making a gadget to do this.
Tackling challenges like this, it's a wonder I don't go stick me willy in a blender for relaxation.
Alan S
There is no sign of oil even in the intake plenum; the valves is it.
Looking at the engine, valve #1 @ the RHS is swimming in it (5mm) #2 is wet, #3 is moist, #4 almost dry, the rest normal.
So far, the beat theory we've come up with is that the valve stem seal was fitted too loosely and the outer portion of the hydraulic cam follower is acting like a piston and compressing the oil between it and the head and the oil is then taking the least line of resistence down past the loose fitting seal and down the valve stem, but is it logical to expect a seal such as this to withstand that kind of pressure or is there a developed fault that is allowing too much oil to be trapped in there (oil return or a relief of some sort) that may be blocked and creating a situation where the oil can be there in such a volume that it is getting compressed? If this were to be the case, it may explain why they have been pulling this engine apart for the past 40,000 klms without success, but to me, I think this is grasping at straws. I intend looking at it in a bit more detail later in the day. I'm trying if at all possible to do this without removing the head.
Has anyone else ever done valve stem seals on one of these engines without removing the head incidentally? That was another challenge; designing and making a gadget to do this.
Tackling challenges like this, it's a wonder I don't go stick me willy in a blender for relaxation.
Alan S
My old master once had an engine (donno the make) he could not make running good doing a standard valve setting. He finally decided to run it with the valve cover removed and surrounded with old blankets to catch the oil spitting. Then he found a cracked rocker arm that flexed a bit.
My point is you should test run the engine w/ valve cover off and look for any strange behaviour. Maybe first simply crank it no ignition on.
Must be possible to see something as that amount of oil does not disappear w/o visible reasons ...
But really I believe it's a head off job to find the conclusive reason [8)]
My point is you should test run the engine w/ valve cover off and look for any strange behaviour. Maybe first simply crank it no ignition on.
Must be possible to see something as that amount of oil does not disappear w/o visible reasons ...
But really I believe it's a head off job to find the conclusive reason [8)]
I'm just ging to state the obvious so that we're talking the same way. No 1 valve is the one nearest the flywheel and no 2 is its partner in the same (no 1 ) cylinder. 3 & 4 are the inlets on cylinder no 2.
Rather thinking aloud here - its got to be head hasn't it - if there was a breather the plenum or some part of it would be messy and unless it went into one of the (long) inlet tracts it would contamminate all.
What's confusing me a bit is why 2 and 3 should be affected. I suppose the oil could come down the outside of the valve guide. I don't know how they are fitted but would expect that the head would be heated before insertion. If some bodger had bashed them out cold he could have enlarged or scored the holes in the head alowing oil to seep past. those for cylinders 3and 4 being done properly?
I suppose the oil circuit is pressure feed to the camshaft bearings then flow and splash for the cams, running around the tappets and into a gallery underneath the head surface from where at (both?) ends of the head it drains into the sump. If one end of this drain were blocked there could I suppose be flooding in the head which would affect from one end and reduce towards the other?
Jeremy - almost baffled!
Rather thinking aloud here - its got to be head hasn't it - if there was a breather the plenum or some part of it would be messy and unless it went into one of the (long) inlet tracts it would contamminate all.
What's confusing me a bit is why 2 and 3 should be affected. I suppose the oil could come down the outside of the valve guide. I don't know how they are fitted but would expect that the head would be heated before insertion. If some bodger had bashed them out cold he could have enlarged or scored the holes in the head alowing oil to seep past. those for cylinders 3and 4 being done properly?
I suppose the oil circuit is pressure feed to the camshaft bearings then flow and splash for the cams, running around the tappets and into a gallery underneath the head surface from where at (both?) ends of the head it drains into the sump. If one end of this drain were blocked there could I suppose be flooding in the head which would affect from one end and reduce towards the other?
Jeremy - almost baffled!
At this stage, it seems that we may have found it.
As I reported, when the valve stem oil seals came out they were fairly loose; as a comparison we removed a seal from the head of an engine that is over at the machine shop and found it was so hard in there we almost had to chisel it out.
Upon comparison, the seals in the Pug engine were found to be different to the ones that came out of the BX16V engine, so it would appear that either faulty or more likely the incorrect seals were fitted, my first suspicion is possibly seals from an 8 valve engine??
More to come. Thanks to all the suggestions and for letting me bounce theories off you.
Alan S
As I reported, when the valve stem oil seals came out they were fairly loose; as a comparison we removed a seal from the head of an engine that is over at the machine shop and found it was so hard in there we almost had to chisel it out.
Upon comparison, the seals in the Pug engine were found to be different to the ones that came out of the BX16V engine, so it would appear that either faulty or more likely the incorrect seals were fitted, my first suspicion is possibly seals from an 8 valve engine??
More to come. Thanks to all the suggestions and for letting me bounce theories off you.
Alan S
Alan,
My money is on worn/wrong or badly fitted stem seals - or a crack in the head. The seals must be really tight on the guides to stop the oil getting down.
As a point of interest the oil drainage slots at the ends of the head were designed to drain off the oil from a vertically mounted engine I reckon. When the engine is tilted forward the bottom of the head and its front edge form a sort of triangle the base of which is no longer horizontal but is raised to the angle of the tilt.
The result of this is that oil is always left in the head in front of the valves when the engine stops as there is no drainage for it. This leaves the stem seals in a sort of oilbath. What happens when the engine is running though is open to conjecture.
Add to this the fact that the engine is not truly horizontal and that is why you see lots of oil at one end and little at the other. It has drained to the lower end and the surplus has gone down the drainage slot as designed. This could explain why you see valves increasingly more oily towards one end of the head.
Hope this is intelligible enough to add something useful to the thread.
My money is on worn/wrong or badly fitted stem seals - or a crack in the head. The seals must be really tight on the guides to stop the oil getting down.
As a point of interest the oil drainage slots at the ends of the head were designed to drain off the oil from a vertically mounted engine I reckon. When the engine is tilted forward the bottom of the head and its front edge form a sort of triangle the base of which is no longer horizontal but is raised to the angle of the tilt.
The result of this is that oil is always left in the head in front of the valves when the engine stops as there is no drainage for it. This leaves the stem seals in a sort of oilbath. What happens when the engine is running though is open to conjecture.
Add to this the fact that the engine is not truly horizontal and that is why you see lots of oil at one end and little at the other. It has drained to the lower end and the surplus has gone down the drainage slot as designed. This could explain why you see valves increasingly more oily towards one end of the head.
Hope this is intelligible enough to add something useful to the thread.
Alan,just noticed your post and wanted to confirm that you are most likely right about the oil seals as I had a similar problem a few year`s ago with a 405 GRi - same basic engine but 8 valve sohc .
It was using vast amounts of oil and was initially wrongly diagnosed as piston rings which I refused to accept as the smoke was mostly seen when sitting in traffic and after initial start up.
After phoning around a few garages to replace the seals I thought I`d have to tackle the job myself as the average quote was around £450 ,then as a last resort I contacted a local "Indie" who quoted me £90 plus vat!.When asked how he could manage it so cheaply he said he`d invested in a tool which could allow him to fit the seals with the head in situ.It was a universal tool which he`d originally bought for a bad batch of Fords which had the said valve stem seal problem.
I was told exactly as described by JBUK above ,that the engine tilt provided the ideal situation for the oil to run through faulty seals which in my case were also attributed to a bad batch(1989 -90) which hardened -up and became brittle after 50k or so.
Hope this helps.
PS that engine went on to complete a further 70k miles and never used another drop of oil!
It was using vast amounts of oil and was initially wrongly diagnosed as piston rings which I refused to accept as the smoke was mostly seen when sitting in traffic and after initial start up.
After phoning around a few garages to replace the seals I thought I`d have to tackle the job myself as the average quote was around £450 ,then as a last resort I contacted a local "Indie" who quoted me £90 plus vat!.When asked how he could manage it so cheaply he said he`d invested in a tool which could allow him to fit the seals with the head in situ.It was a universal tool which he`d originally bought for a bad batch of Fords which had the said valve stem seal problem.
I was told exactly as described by JBUK above ,that the engine tilt provided the ideal situation for the oil to run through faulty seals which in my case were also attributed to a bad batch(1989 -90) which hardened -up and became brittle after 50k or so.
Hope this helps.
PS that engine went on to complete a further 70k miles and never used another drop of oil!
Of course the inlet camshaft is on top and the exhaust camshaft is lower and up against the bulkhead.
there are 2 problems with replacing the seals in situ - neither of which cannot be conquered. The first one is how to stop the valve dropping - and there are 2 common ways of doing this - 1 is to use compressed air fed in through the spark plug hole with a suitable connector, the other is simply to feed fine rope or string into the cylinder through the plug hole and turn the crank to compress the rope and hold the valves in place.
The other problem is how to compress the valve spring sufficiently to allow the collets to be removed and this may call for some ingenuity!
jeremy
there are 2 problems with replacing the seals in situ - neither of which cannot be conquered. The first one is how to stop the valve dropping - and there are 2 common ways of doing this - 1 is to use compressed air fed in through the spark plug hole with a suitable connector, the other is simply to feed fine rope or string into the cylinder through the plug hole and turn the crank to compress the rope and hold the valves in place.
The other problem is how to compress the valve spring sufficiently to allow the collets to be removed and this may call for some ingenuity!
jeremy
Jeremy,
We've got them out OK by designing a making a tool that literally bolts to the holes the cam bearing carrier bolts onto and operates like a big bottle capper. We have a fitting with a non return valve attached and of course, when the camshafts are out, all valves are in a closed position and we feed 120 psi into it to hold it. Taking them out using this thing was extremely simple.
We're now upending the garage looking for the set of 16V valve stem seals so we can carry on a bit further; they're one of those things that when you ask where they are, every answer begins with "Well; the last time I saw them, they were...."
Does anyone know if or what the difference is between the 8 and 16V engines' valve stem seals?
The comparison we've made between the ones in this engine and the ones out of the other is that this one had seals that the rubber(?) was green in whereas the others were black. The metal section on the green ones seems to be about 10 - 20 thou smaller in diameter than the black and the rubber section on the green ones seems to be only 75% the height of the black ones.
I just wonder whether it's a difference in model or just a different manufacturer. I suspect it may have been a case of trying to cut corners by replacing the intake side and not the exhaust (that's just an assumption based on no facts) and deciding to save a few pence to buy an 8 valve set instead of a 16 or more likely out here, a slack parts guy simply selling one type of seal or only having one available or a company selling general parts that don't know two types of engines exist?
<b>Can anyone tell me if there is a difference in valve stem seals between these two engines????????</b> Please.
Alan S
We've got them out OK by designing a making a tool that literally bolts to the holes the cam bearing carrier bolts onto and operates like a big bottle capper. We have a fitting with a non return valve attached and of course, when the camshafts are out, all valves are in a closed position and we feed 120 psi into it to hold it. Taking them out using this thing was extremely simple.
We're now upending the garage looking for the set of 16V valve stem seals so we can carry on a bit further; they're one of those things that when you ask where they are, every answer begins with "Well; the last time I saw them, they were...."
Does anyone know if or what the difference is between the 8 and 16V engines' valve stem seals?
The comparison we've made between the ones in this engine and the ones out of the other is that this one had seals that the rubber(?) was green in whereas the others were black. The metal section on the green ones seems to be about 10 - 20 thou smaller in diameter than the black and the rubber section on the green ones seems to be only 75% the height of the black ones.
I just wonder whether it's a difference in model or just a different manufacturer. I suspect it may have been a case of trying to cut corners by replacing the intake side and not the exhaust (that's just an assumption based on no facts) and deciding to save a few pence to buy an 8 valve set instead of a 16 or more likely out here, a slack parts guy simply selling one type of seal or only having one available or a company selling general parts that don't know two types of engines exist?
<b>Can anyone tell me if there is a difference in valve stem seals between these two engines????????</b> Please.
Alan S
Jeremy, availability may not necessarily be a problem for me, I'm looking at if they're different and if so why the previous people have fitted them and not the correct ones, what the problem was that they ended up getting them as over here, "Urban myths" run riot, so if he's been supplied with the wrong ones, I'm trying to avoid someone setting me up with the same (incorrect) ones and using the same story on me they used on the previous owners.
All this of course becomes irrelevant if I can find my set for a 16V that I know I have here.
Alan S
All this of course becomes irrelevant if I can find my set for a 16V that I know I have here.
Alan S