Air Box Oil Breather - anyone found a catch tank / solution?
Discussion
Has anyone come up with a decent solution for the oil breather / air box problem?
I'm quite new to Cerbera's, and now the weather is improving have been starting to "give it some beans"
and starting to enjoy the cars performance.... what a car!
However, I just noticed smoke coming from the right hand bonnet vent, and on investigation there's oil over the right hand (drivers side) top of the engine, which is dripping down onto the hot manifolds and causing the smoke. At the end of a decent run, there was also oil gathered behind the front number plate.....
I sh
t myself, thinking I'd blown a head gasket......
I always ensure that the dipstick shows at least half way between max & min, and had topped the oil up to show Max.
Speaking to Joo about this on the phone, he indicated that this is probably a common problem with the oil breather filling the drivers side airbox with oil, and it leaking out; and that people often experience the oil behind the number plate after track days when the car has been given a good thrashing.
Anyone else get this problem?
Has anyone come up with a catch tank or resevoir, which helps with this issue? Ideally should it be able to drain back into the sump afterwards to stop having to manually empty? How much oil can be expected to be lost / collected by this?
Help! I don't particularly want to be venting oil smoke from the bonnet when stationally after a good run.....
I'm quite new to Cerbera's, and now the weather is improving have been starting to "give it some beans"
and starting to enjoy the cars performance.... what a car!However, I just noticed smoke coming from the right hand bonnet vent, and on investigation there's oil over the right hand (drivers side) top of the engine, which is dripping down onto the hot manifolds and causing the smoke. At the end of a decent run, there was also oil gathered behind the front number plate.....
I sh
t myself, thinking I'd blown a head gasket...... I always ensure that the dipstick shows at least half way between max & min, and had topped the oil up to show Max.
Speaking to Joo about this on the phone, he indicated that this is probably a common problem with the oil breather filling the drivers side airbox with oil, and it leaking out; and that people often experience the oil behind the number plate after track days when the car has been given a good thrashing.
Anyone else get this problem?
Has anyone come up with a catch tank or resevoir, which helps with this issue? Ideally should it be able to drain back into the sump afterwards to stop having to manually empty? How much oil can be expected to be lost / collected by this?
Help! I don't particularly want to be venting oil smoke from the bonnet when stationally after a good run.....
See previous threads;
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
The problems you are experiencing are due to a very poor breather design as standard. Being a relatively 'loose' race engine, the AJP8 does generate quite a lot of blow-by. Since there is only one breather outlet for the whole engine, the stock setup spits far too much oil mist into the drivers side air intake when driven hard.
If you use a catch tank with baffle plate and perhaps stainless steel pads stuffed in as well to help draw out the oil AND vent the remains between box airboxes, the problem goes away.
I remember reading about this on the internet somewhere. The engine breathing on the AJP8 is marginal because it was originally designed to be a dry sumped engine. These engines have scavenge pumps which help to reduce crankcase pressure. When it was changed to wet sump for the road cars they forgot to address the blowby issue - most race engines have multiple breathers for both the top and bottom end.
You could vent to atmosphere but then you will get an oil film all over the engine bay.
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
The problems you are experiencing are due to a very poor breather design as standard. Being a relatively 'loose' race engine, the AJP8 does generate quite a lot of blow-by. Since there is only one breather outlet for the whole engine, the stock setup spits far too much oil mist into the drivers side air intake when driven hard.
If you use a catch tank with baffle plate and perhaps stainless steel pads stuffed in as well to help draw out the oil AND vent the remains between box airboxes, the problem goes away.
I remember reading about this on the internet somewhere. The engine breathing on the AJP8 is marginal because it was originally designed to be a dry sumped engine. These engines have scavenge pumps which help to reduce crankcase pressure. When it was changed to wet sump for the road cars they forgot to address the blowby issue - most race engines have multiple breathers for both the top and bottom end.
You could vent to atmosphere but then you will get an oil film all over the engine bay.
Thanks for the responses 
And also to Pete who sent me some photo's of a neat install.
I quite like the look of this option from one of the previous threads - anyone got a photo of one fitted?
http://shop1.actinicexpress.co.uk/shops/Rat_Sport/...
And also to Pete who sent me some photo's of a neat install.
I quite like the look of this option from one of the previous threads - anyone got a photo of one fitted?
http://shop1.actinicexpress.co.uk/shops/Rat_Sport/...
Not 100% sure why anyone would plumb in a catch tank when you have a really large one running on the Cerb called the right hand airbox.
Crank case pressure causes the oil to be pushed up through an anti splash wire wool pad in a tank below the right airbox.
The tank is about the size of a cup. More than this overflows the tank into the right hand airbox itself.
However its not a one way valve, and when the engine stops, or the pressure lowers, the airbow will self drain back through the wire wool cup into the engine. Presto.
The vaccum in the airbox isn't anywhere near enough to suck the oil up into the inlets, and they are a fair way up the side of the airbow so the trickle of overflow oil isn't going to splash up there.
The reason it doesn't work well normally is that the seal between the cup and airbox dies, or the pathetic self tappers through glassfibre obviously work loose with age causing a gap and leakage which then drops onto the hot exhaust manifold.
I sorted mine by removing the lot. Putting a new gasket in and some rivnuts. Now it does up with proper bolts of the sort that can be tightened like a normal nut bolt with no chance of loosening or leakage.
Job done works a treat, and no need to find space for a catch tank, let alone the problem of auto emptying.
Crank case pressure causes the oil to be pushed up through an anti splash wire wool pad in a tank below the right airbox.
The tank is about the size of a cup. More than this overflows the tank into the right hand airbox itself.
However its not a one way valve, and when the engine stops, or the pressure lowers, the airbow will self drain back through the wire wool cup into the engine. Presto.
The vaccum in the airbox isn't anywhere near enough to suck the oil up into the inlets, and they are a fair way up the side of the airbow so the trickle of overflow oil isn't going to splash up there.
The reason it doesn't work well normally is that the seal between the cup and airbox dies, or the pathetic self tappers through glassfibre obviously work loose with age causing a gap and leakage which then drops onto the hot exhaust manifold.
I sorted mine by removing the lot. Putting a new gasket in and some rivnuts. Now it does up with proper bolts of the sort that can be tightened like a normal nut bolt with no chance of loosening or leakage.
Job done works a treat, and no need to find space for a catch tank, let alone the problem of auto emptying.
julian64 said:
Not 100% sure why anyone would plumb in a catch tank when you have a really large one running on the Cerb called the right hand airbox.
Crank case pressure causes the oil to be pushed up through an anti splash wire wool pad in a tank below the right airbox.
The tank is about the size of a cup. More than this overflows the tank into the right hand airbox itself.
However its not a one way valve, and when the engine stops, or the pressure lowers, the airbow will self drain back through the wire wool cup into the engine. Presto.
The vaccum in the airbox isn't anywhere near enough to suck the oil up into the inlets, and they are a fair way up the side of the airbow so the trickle of overflow oil isn't going to splash up there.
The reason it doesn't work well normally is that the seal between the cup and airbox dies, or the pathetic self tappers through glassfibre obviously work loose with age causing a gap and leakage which then drops onto the hot exhaust manifold.
I sorted mine by removing the lot. Putting a new gasket in and some rivnuts. Now it does up with proper bolts of the sort that can be tightened like a normal nut bolt with no chance of loosening or leakage.
Job done works a treat, and no need to find space for a catch tank, let alone the problem of auto emptying.
I was quite happy to re-new the original set on mine but couldn't find a replacement filter 'cup' as you say...only option was an alloy for approx. £140...Crank case pressure causes the oil to be pushed up through an anti splash wire wool pad in a tank below the right airbox.
The tank is about the size of a cup. More than this overflows the tank into the right hand airbox itself.
However its not a one way valve, and when the engine stops, or the pressure lowers, the airbow will self drain back through the wire wool cup into the engine. Presto.
The vaccum in the airbox isn't anywhere near enough to suck the oil up into the inlets, and they are a fair way up the side of the airbow so the trickle of overflow oil isn't going to splash up there.
The reason it doesn't work well normally is that the seal between the cup and airbox dies, or the pathetic self tappers through glassfibre obviously work loose with age causing a gap and leakage which then drops onto the hot exhaust manifold.
I sorted mine by removing the lot. Putting a new gasket in and some rivnuts. Now it does up with proper bolts of the sort that can be tightened like a normal nut bolt with no chance of loosening or leakage.
Job done works a treat, and no need to find space for a catch tank, let alone the problem of auto emptying.
As stated by others the standard set up has proved less than effecive...? I have no personal experience of this other than mine was split and cracked and leaking / spraying oil everywhere!
I was going to do what you did but then got to thinking about a separate breather / oil catch tank...this is the way I went.
One of the main reasons I did it was that I was told there is no reason for discharging the oil / oil vapour into the air box other than to get rid of it by burning it off via the engine...If there is a significant amount then maybe this could damage the CATS (if the car has any...)? Someone also thought that blowing oil vapour into the air box lowered the octane rating of the fuel / air mix...? Can't see this being by much but you never know...every horse counts right!
Sure both solutions work...each to their own I guess...
peteA said:
julian64 said:
Not 100% sure why anyone would plumb in a catch tank when you have a really large one running on the Cerb called the right hand airbox.
Crank case pressure causes the oil to be pushed up through an anti splash wire wool pad in a tank below the right airbox.
The tank is about the size of a cup. More than this overflows the tank into the right hand airbox itself.
However its not a one way valve, and when the engine stops, or the pressure lowers, the airbow will self drain back through the wire wool cup into the engine. Presto.
The vaccum in the airbox isn't anywhere near enough to suck the oil up into the inlets, and they are a fair way up the side of the airbow so the trickle of overflow oil isn't going to splash up there.
The reason it doesn't work well normally is that the seal between the cup and airbox dies, or the pathetic self tappers through glassfibre obviously work loose with age causing a gap and leakage which then drops onto the hot exhaust manifold.
I sorted mine by removing the lot. Putting a new gasket in and some rivnuts. Now it does up with proper bolts of the sort that can be tightened like a normal nut bolt with no chance of loosening or leakage.
Job done works a treat, and no need to find space for a catch tank, let alone the problem of auto emptying.
I was quite happy to re-new the original set on mine but couldn't find a replacement filter 'cup' as you say...only option was an alloy for approx. £140...Crank case pressure causes the oil to be pushed up through an anti splash wire wool pad in a tank below the right airbox.
The tank is about the size of a cup. More than this overflows the tank into the right hand airbox itself.
However its not a one way valve, and when the engine stops, or the pressure lowers, the airbow will self drain back through the wire wool cup into the engine. Presto.
The vaccum in the airbox isn't anywhere near enough to suck the oil up into the inlets, and they are a fair way up the side of the airbow so the trickle of overflow oil isn't going to splash up there.
The reason it doesn't work well normally is that the seal between the cup and airbox dies, or the pathetic self tappers through glassfibre obviously work loose with age causing a gap and leakage which then drops onto the hot exhaust manifold.
I sorted mine by removing the lot. Putting a new gasket in and some rivnuts. Now it does up with proper bolts of the sort that can be tightened like a normal nut bolt with no chance of loosening or leakage.
Job done works a treat, and no need to find space for a catch tank, let alone the problem of auto emptying.
As stated by others the standard set up has proved less than effecive...? I have no personal experience of this other than mine was split and cracked and leaking / spraying oil everywhere!
I was going to do what you did but then got to thinking about a separate breather / oil catch tank...this is the way I went.
One of the main reasons I did it was that I was told there is no reason for discharging the oil / oil vapour into the air box other than to get rid of it by burning it off via the engine...If there is a significant amount then maybe this could damage the CATS (if the car has any...)? Someone also thought that blowing oil vapour into the air box lowered the octane rating of the fuel / air mix...? Can't see this being by much but you never know...every horse counts right!
Sure both solutions work...each to their own I guess...
There isn't any significant take of oil into the inlets, for the reasons above.
Empirically if there were three things would happen, constant blue smoke out of the right exhaust pipe, and engine that faltered, and losing a boat load of oil on a regular basis. Even a very small regular amount would cause rapid fouling of the right bank plugs.
None of that happens to my car.
A catch tank is certainly an alternative used by some. I just don't see a good reason to put something metal in front of a car engine that needs all the cooling it can get.
Julian, I have to disagree with you here. If you accept that the AJP8 is effectively a race engine then you find me a race engine that doesn't use a catch tank or some other elaborate crank ventilation system (e.g. exhaust manifold vacuum devices). Nearly all track-day spec cars have them fitted, turbo or na. Maybe your car is different to mine, but when I noticed the oil collecting in the airbox I also had a thin but definite oil film inside the intake trumpets so the engine must have been ingesting oil mist. I found that after hard driving, this oil film was sufficient to effectively stall that bank of air at idle (chocking the very small clearances around the butterflies) and the engine would cut out. Never happened after the catch tank was fitted.
I would only suggest a proper catch tank for cars that do frequent trackdays, but even for road cars it keeps the intakes clean during hard driving. As for cooling of the engine, I can't see how a catch tank is going to make any difference at all TBH.
Also oil vapour in the intake effectively lowers the octane rating of the fuel/air mixture which isn't great. Added to the fact that the AJP8 has no knock sensor(s), its wise to keep the octane rating as high as possible.
The internet is full of this stuff, a quick example is;
http://www.optionimports.com/meraoilcacan.html
I would only suggest a proper catch tank for cars that do frequent trackdays, but even for road cars it keeps the intakes clean during hard driving. As for cooling of the engine, I can't see how a catch tank is going to make any difference at all TBH.
Also oil vapour in the intake effectively lowers the octane rating of the fuel/air mixture which isn't great. Added to the fact that the AJP8 has no knock sensor(s), its wise to keep the octane rating as high as possible.
The internet is full of this stuff, a quick example is;
http://www.optionimports.com/meraoilcacan.html
Mine is not an ajp obviously, but i have been catch tanking myself, i have mounted an alloy one on the inside wing. I have one breather that goes from the valley to just behind the throttle body,(so no catch tank on this part of the circuit) this is meant to create a vacuum to release the effects of the blow by, and so it is said may improve ring seal. I then have a breather on each rocker, (std is only one side) and these are then routed to the catch tank. Interestingly if i disconnect the valley vacuum, oil mist INSTANTLY comes out of the rocker breathers. Dunno whether this might be something that might work on an ajp?
smash][fez]Nice prices - looky looky!
longbow said:
Julian, I have to disagree with you here. If you accept that the AJP8 is effectively a race engine then you find me a race engine that doesn't use a catch tank or some other elaborate crank ventilation system (e.g. exhaust manifold vacuum devices). Nearly all track-day spec cars have them fitted, turbo or na. Maybe your car is different to mine, but when I noticed the oil collecting in the airbox I also had a thin but definite oil film inside the intake trumpets so the engine must have been ingesting oil mist. I found that after hard driving, this oil film was sufficient to effectively stall that bank of air at idle (chocking the very small clearances around the butterflies) and the engine would cut out. Never happened after the catch tank was fitted.
I would only suggest a proper catch tank for cars that do frequent trackdays, but even for road cars it keeps the intakes clean during hard driving. As for cooling of the engine, I can't see how a catch tank is going to make any difference at all TBH.
Also oil vapour in the intake effectively lowers the octane rating of the fuel/air mixture which isn't great. Added to the fact that the AJP8 has no knock sensor(s), its wise to keep the octane rating as high as possible.
The internet is full of this stuff, a quick example is;
http://www.optionimports.com/meraoilcacan.html
Maybe you're right as I don't do many track days. In fact none last year I would only suggest a proper catch tank for cars that do frequent trackdays, but even for road cars it keeps the intakes clean during hard driving. As for cooling of the engine, I can't see how a catch tank is going to make any difference at all TBH.
Also oil vapour in the intake effectively lowers the octane rating of the fuel/air mixture which isn't great. Added to the fact that the AJP8 has no knock sensor(s), its wise to keep the octane rating as high as possible.
The internet is full of this stuff, a quick example is;
http://www.optionimports.com/meraoilcacan.html
.markh1 said:
smash][fez]Nice prices - looky looky!
Thanks for all the responses guys.
I've been speaking with Joo and he knows a local fabricator who builds stuff for race cars etc. I'm going to book it in over the next few weeks, and I'll let you know how I get on.
Ideally I'm lloking for a neat solution that can drain the oil back into the engine, rather than something that I need to empty out.
Definitely going to do this, as getting oil on the exhaust and behind the front number plate after a "spirited" drive......
I've been speaking with Joo and he knows a local fabricator who builds stuff for race cars etc. I'm going to book it in over the next few weeks, and I'll let you know how I get on.
Ideally I'm lloking for a neat solution that can drain the oil back into the engine, rather than something that I need to empty out.
Definitely going to do this, as getting oil on the exhaust and behind the front number plate after a "spirited" drive......
As an experipent I used an old 5ltr plastic container with some 25mm platic conduit and some push in fittings. Wedged it down between the right hand intake duct and the inner wing. After a recent track day it collected 0.6 of a litre of c**p. Brown liquid that look like it had been in a blender for a week and had a really acrid smell. Cant see it doing any good if it went back into the engine. May look at doing something a bit more permentant.
just seen these pop up on eBay for those looking at a solution. Not sure on quality.
http://tinyurl.com/catchtank1
http://tinyurl.com/catchtank2
not sure if these is related - when mine has high revs, and being thrown around a bit and sudden stops i get the smoke from oil, not sure if its coming through the oil breather? maybe i'll look into this aswell.
any other solutions?
http://tinyurl.com/catchtank1
http://tinyurl.com/catchtank2
not sure if these is related - when mine has high revs, and being thrown around a bit and sudden stops i get the smoke from oil, not sure if its coming through the oil breather? maybe i'll look into this aswell.
any other solutions?
The Cerb was in with Joo to get the local fabricator to take measurements etc. This guy comes recommended by Joo, and is working with the A1 race series - so on the basis that it's good enough for top flight race teams, etc......
We are working on a design to sit just infront of the drivers side airbox, and one that drains the vented oil back into the engine so I don't need to faff about draining the tank etc.
I'll be popping back in to see Joo and the fabricator next week, will keep you posted on how we get on.
We are working on a design to sit just infront of the drivers side airbox, and one that drains the vented oil back into the engine so I don't need to faff about draining the tank etc.
I'll be popping back in to see Joo and the fabricator next week, will keep you posted on how we get on.
Wahey!!! Just got note from Joo that the newly fabricated breather is on the car!
But I'm working away and won't see it until Tuesday 9th June
But then I get to "test" it under (cough) controlled conditions (cough) on the run down to LE MANS
Roll on Le Mans!!!!!!!!!!!!!!!!!!!!
Anyone at Le Mans can come and see me at Houx - it'll beat me getting a photo on this thread
But I'm working away and won't see it until Tuesday 9th June
But then I get to "test" it under (cough) controlled conditions (cough) on the run down to LE MANS
Roll on Le Mans!!!!!!!!!!!!!!!!!!!!
Anyone at Le Mans can come and see me at Houx - it'll beat me getting a photo on this thread
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