DB9, problem with oiled up Air Filters
Discussion
drofnavi said:
What do you think of my suggestion for mounting the catch tank inside the wheel arch.
I'm going to go with it. To be honest I can't see a better place for it to go. I changed the exhaust, so I have loads of space where the old baffle used to go, the problem is, taking in account going around corners etc, it about 5 metre to the tank, I think that is too far, the oil vapour will cool, condense and then block. But that's only me talking out of my ..... so I could be completely wrong. I think 5 metre is too far to go. Then there is the fixing problems. So, yes, the wheel arch looks good. Probably go with one in each arch, only because I don't want to be emptying it every 5 minutes. This way, they can fill up and I'll look every 3 months. 
Hello again ..... after working on the rest of the engine I am now looking at trying to sort this matter out. I have looked at the 2 throttle bodies and there are 2 airintake pipes on the passenger side and 3 on the drivers side, I have put these photos on this thread to show them ....
The above photo shows the passenger side throttle valve, there is clearly the pipe coming from the centre of the engine.
The above photo shows the same throttle, but from the side, I have pointed a screw driver at the other pipe. Does this pipe also need to be diverted?
The above photo shows the drivers side throttle, there is again the pipe coming from the centre of the V12, but you can also see a braided black thicker pipe coming from the other side, this comes from a pipe from the back of the engine.
The above photo shows the drivers throttle and a third (3rd) pipe coming in from below, I have pointed a screw driver at the pipe in question.
My question is, do I need to divert all 5 pipes to the catch tanks? Or just the top 2? Where are the other 3 coming from? Why is there 2 on one side and 3 on the other?
Thanks ........
The above photo shows the passenger side throttle valve, there is clearly the pipe coming from the centre of the engine.
The above photo shows the same throttle, but from the side, I have pointed a screw driver at the other pipe. Does this pipe also need to be diverted?
The above photo shows the drivers side throttle, there is again the pipe coming from the centre of the V12, but you can also see a braided black thicker pipe coming from the other side, this comes from a pipe from the back of the engine.
The above photo shows the drivers throttle and a third (3rd) pipe coming in from below, I have pointed a screw driver at the pipe in question.
My question is, do I need to divert all 5 pipes to the catch tanks? Or just the top 2? Where are the other 3 coming from? Why is there 2 on one side and 3 on the other?
Thanks ........
Here goes, and I'll risk being shot down!
My understanding is that the two small pipes that feed into the downstream of the throttle body are the primary ventilation system, any vapours get ingested and burned by the engine, the pipe below the throttle body on the passenger side feeds air from upstream of the throttle body (i.e. the rubber pipe) to the back of the engine through a series of PCV valves that connect to the vents in the centre of the 'V', inturn the secondary ventilation system comes into play when the engine is under greater load and exits from the rear of the engine down the drivers side cam cover and connects to the upstream (rubber pipe) on the drivers side throttle body.
My understanding is that the two small pipes that feed into the downstream of the throttle body are the primary ventilation system, any vapours get ingested and burned by the engine, the pipe below the throttle body on the passenger side feeds air from upstream of the throttle body (i.e. the rubber pipe) to the back of the engine through a series of PCV valves that connect to the vents in the centre of the 'V', inturn the secondary ventilation system comes into play when the engine is under greater load and exits from the rear of the engine down the drivers side cam cover and connects to the upstream (rubber pipe) on the drivers side throttle body.
drofnavi said:
Have all of these pipes got oil inside of them. If not I would initially onle repipe the oily ones.
I was of this opinion, I will check them and see which ones are oily and hope to only bypass them. I bet its the hard ones that are oily.B1, where did you learn this stuff ....? you don't want to pop down and help do you?
So which ones do you think need changing?I have to stress this is just my opinion, but, if it was my car, my thinking would be as follows:
The primary vents(i.e. the small pipes connected to the downstream of the throttle bodies) have to be assumed to be doing their job, the failure in the system has to be the PCV's, when under load allowing oil vapour to migrate down both larger pipes (eithier side of the cam covers) into the upstream of the intake system, when the engine is off, oil that is suspended in the pipes drips down to the air filters.
It's a pity you didn't replace the PCV's while the manifolds were off, again if it was my car, I would initially vent the secondary vent system pipes on the drivers side to atmosphere (vent tank) and observe on a regular basis.
Hope this helps.
The primary vents(i.e. the small pipes connected to the downstream of the throttle bodies) have to be assumed to be doing their job, the failure in the system has to be the PCV's, when under load allowing oil vapour to migrate down both larger pipes (eithier side of the cam covers) into the upstream of the intake system, when the engine is off, oil that is suspended in the pipes drips down to the air filters.
It's a pity you didn't replace the PCV's while the manifolds were off, again if it was my car, I would initially vent the secondary vent system pipes on the drivers side to atmosphere (vent tank) and observe on a regular basis.
Hope this helps.
Edited by B1 ECC on Thursday 24th January 21:08
Edited by B1 ECC on Thursday 24th January 22:01
drofnavi said:
I have sent you a PM
B1, I would have loved to change the PCV's, but they would just not come out, you need to take one of the Cyd heads off to get them out. I can see pretty much you are saying what drofnavi is saying, vent the ones that are causing the problem, and you think its the ones that are the fatter pipes under the throttle bodies. Brilliant, I have all the pipes for the top pipes and now I'll have a look at the bottom ones.
I'll give all the pipes a pull and see which ones are oily, then see what is going on .....
Thanks
Just posting a few photos of hoses that have and have not caused me problems, its just for clarification ....
The above photo shows the passenger side throttle control, the pipe on the tope was a main oil provider, I pushed a rag up into the pipe and it came out oily.
The above photo shows the drivers side throttle body, this is the lower 1/2inch pipe, this was full of oil, this will need to be re-routed.
The above photo shows the drivers side throttle body, the small pipe on the left was crystal clear, so that will not be re-routed, I have decided to change the black braided pipe for a Stainless Steel one, purely for looks. The one on the right was full of oil and so will be re-routed.
The above photo shows some braided pipes already put in place. I have to blank off the 2 nipples that are 3/8 inch and 2 that are 1/2 inch. I am having to do this very crudly because I have no blacking stop ends. I have ordered them from Samco, but they will not be here for a week or so yet, so I am stuck with some crude makeshift stop end.
I will work on them tomorrow and see if I can truly polish a turd ..... as well as re-route some pipes and tie them all back safe.
One question, I can easily connect one throttle body to the other, both the 3/8 and the 1/2, I feel I can do the 1/2 inch without took much trouble, that is link the left and right together, the 1/2inch is before the throttle butterfly valves, but the 3/8 inch are AFTER the butterfly valves.
Anyone have any thoughts if this would cause any problems?
The above photo shows the passenger side throttle control, the pipe on the tope was a main oil provider, I pushed a rag up into the pipe and it came out oily.
The above photo shows the drivers side throttle body, this is the lower 1/2inch pipe, this was full of oil, this will need to be re-routed.
The above photo shows the drivers side throttle body, the small pipe on the left was crystal clear, so that will not be re-routed, I have decided to change the black braided pipe for a Stainless Steel one, purely for looks. The one on the right was full of oil and so will be re-routed.
The above photo shows some braided pipes already put in place. I have to blank off the 2 nipples that are 3/8 inch and 2 that are 1/2 inch. I am having to do this very crudly because I have no blacking stop ends. I have ordered them from Samco, but they will not be here for a week or so yet, so I am stuck with some crude makeshift stop end.
I will work on them tomorrow and see if I can truly polish a turd ..... as well as re-route some pipes and tie them all back safe.
One question, I can easily connect one throttle body to the other, both the 3/8 and the 1/2, I feel I can do the 1/2 inch without took much trouble, that is link the left and right together, the 1/2inch is before the throttle butterfly valves, but the 3/8 inch are AFTER the butterfly valves.
Anyone have any thoughts if this would cause any problems?
I would be surprised if the pipes on the engine side of the throttle butterflies would leak oil into the air filters. On a closed throttle there is a fair vacuum in there, that would suck any oil in there immediately into the combustion chambers.
It's the pipes at the athmosphere side that are causing the problem.
It's the pipes at the athmosphere side that are causing the problem.
MaverickV12 said:
Anyone have any thoughts if this would cause any problems?
To be clear.... All you should be doing is modifying the factory schematic / layout by introducing catch tanks into the return circuits to the engine? The objective is to simply separate engine oil from normal (and required) breather gas flow. If you intend doing anything other than this..... re think your idea..!Good luck
drofnavi said:
I would be surprised if the pipes on the engine side of the throttle butterflies would leak oil into the air filters. On a closed throttle there is a fair vacuum in there, that would suck any oil in there immediately into the combustion chambers.
It's the pipes at the athmosphere side that are causing the problem.
You're right the pipes behind the valves do have a fair old vacuum, and I can see that not much oil would drain down to the airfilters, but I'm concerned that any oil is being burnt by the engine. If the PCV valves are not doing what they should be doing and oil is finding its way into the airway system, then even if its after the butterfly valves, then I would rather it drain away than burn it.It's the pipes at the athmosphere side that are causing the problem.
Especially if the unbalanced sides of the V12 might be causing a problem with the Tunnel ticking issue......
Bamfordmike, I think I see what your're saying, drain the pipes as discussed, if I were to start redesigning AM's engine, that might not be the best idea. So keep the 2 sides sperate, drain the oil, don't connect the two 3/8 inch and two 1/2inch inlets on the butterfly manifold....
I think I have it right ....... !
Here’s a very simplistic schematic of the Crankcase ventilation system on the DB9 (please feel free to comment on any errors). It shows the flow paths and orientations of the various check valves in the system.
The only parts of the system that are connected to the larger pipe going to the right inlet duct (your second picture above) are the oil separators, the (No4) relief valve and the right hand (No3) check valve. If either the No3 or No4 valve has failed then this may be causing the oil carry over. I would be checking all five valves first before making any modifications.
AMV12, 7 months and 1 post ......... !!! 
where have you been .........?
It would appear that I have oil in all 4 of the pipes, I don't know how common it is for these valves to fail, or bung up, but what ever they are, mine are not working. It would appear that the oil pressure (in gas form) comes from the engine and then the 2 camshaft covers.
For the minute, I think I will redirect the 2 x 3/8 and 2 x 1/2 inch pipes.
AMV you have put initials for the 5th pipe that does not seem connected to the engine directly, can you tell us what they stand for ....?
Good drawing ... where did you get it from ? You draw this yourself?
where have you been .........? It would appear that I have oil in all 4 of the pipes, I don't know how common it is for these valves to fail, or bung up, but what ever they are, mine are not working. It would appear that the oil pressure (in gas form) comes from the engine and then the 2 camshaft covers.
For the minute, I think I will redirect the 2 x 3/8 and 2 x 1/2 inch pipes.
AMV you have put initials for the 5th pipe that does not seem connected to the engine directly, can you tell us what they stand for ....?
Good drawing ... where did you get it from ? You draw this yourself?
I wouldn't disconnect the two smaller pipes connected upstream of the butterfly, as you said there is a vacuum present and this vacuum 'Signal' opens and closes the PCV valves. I'm not sure how many PCV's there are but if any of them are working you would want them to continue. To start, I would only vent the large pipe under the drivers side throttle to atmosphere (Catch Tank). If you change to many things at once it will be harder to identify which one worked!
Good luck
Good luck
Edited by B1 ECC on Monday 28th January 08:20
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