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well this thing is crazy LOL

im running Dunlop sports tyres 295 and just spins them up need to learn throtle control abit better..

Though im getting abit of blow by into my catch can so need to sort this out been thinking of adding a secondary catch can that sits ontop of the covers then breathers going into anther can..

maybe even a return into the sump..

well this thing is crazy LOL

im running Dunlop sports tyres 295 and just spins them up need to learn throtle control abit better..

Though im getting abit of blow by into my catch can so need to sort this out been thinking of adding a secondary catch can that sits ontop of the covers then breathers going into anther can..

maybe even a return into the sump..

Wait until you track it and see if it blows oil as well.

I think I have solved the problem not with a drain to the sump but with a sump breather. I installed two 1/2 in outlets from the sump - the intention was one for a breather and the other for an oil return but in fact they are both function as breathers at the moment. Very little oil comes out (and what does could be attributed to the fact that it is well overfilled) but a fair amount of air comes out - not necessarily blow by but possibly pressure created by the crank.

Wait until you track it and see if it blows oil as well.

I think I have solved the problem not with a drain to the sump but with a sump breather. I installed two 1/2 in outlets from the sump - the intention was one for a breather and the other for an oil return but in fact they are both function as breathers at the moment. Very little oil comes out (and what does could be attributed to the fact that it is well overfilled) but a fair amount of air comes out - not necessarily blow by but possibly pressure created by the crank.

ok so before you added the breather you had the catch can filling up?

also how is your pvc hooked up? & your breather setup how have you made that work?

i plumbed up the drain back to the sump but it is still filling up the catch can.. though i only have a 1 litre catch can cause of no room.. been trying to get a fabricator to make one as big as possible whith the room have.

ok so before you added the breather you had the catch can filling up?

also how is your pvc hooked up? & your breather setup how have you made that work?

i plumbed up the drain back to the sump but it is still filling up the catch can.. though i only have a 1 litre catch can cause of no room.. been trying to get a fabricator to make one as big as possible whith the room have.

I am currently evaluating progress and waiting for my next track day to decide on a permanent set up but I have two catch cans at present. The two breathers from the sump go into one catch can which is vented to atmos atm. The pvc hole is blocked off. The two breathers on the cam covers go to another catch can which is also vented to atmos. There is no oil going into the catch can from the cam covers now (as opposed to heaps before). There was one episode where oil went into the other catch can from the sump breathers but that could be because I overfilled it by a couple of litres (not as bad as it sounds because there is a 10mm adapter plate between the RB30 and my awd sump). I think the combination of smaller restrictors and the vents on the sump have done the trick. There is quite a bit of pressure built up in the sump and part of the theory is that this impedes the flow of oil back to the sump so it goes out the top instead.

If there is no more oil as such coming out when at the track I would be keen to fit a proper oil/air seperator or a properly baffled "catch can" and then have the catch can vented to an inlet somewhere so that the is some suction applied to the sump and also nothing going to atmosphere.

Actually its going on the dyno on Friday so this will probably be a good test as last time it also spewed out oil everywhere after a few seconds high speed running under load.

Have you got a drain from the head to the sump? Does it run to a new fitting? As an experiment try disconnecting the drain from the sump and putting it into a temporary container (to see how much if any oil comes out that way) and fitting a breather hose to the inlet/outlet in the sump and running that up to a catch can if you have a spare or just poke it into any vented or open container and see what happens. Have you got restrictors in the oil supply to the head?

I am currently evaluating progress and waiting for my next track day to decide on a permanent set up but I have two catch cans at present. The two breathers from the sump go into one catch can which is vented to atmos atm. The pvc hole is blocked off. The two breathers on the cam covers go to another catch can which is also vented to atmos. There is no oil going into the catch can from the cam covers now (as opposed to heaps before). There was one episode where oil went into the other catch can from the sump breathers but that could be because I overfilled it by a couple of litres (not as bad as it sounds because there is a 10mm adapter plate between the RB30 and my awd sump). I think the combination of smaller restrictors and the vents on the sump have done the trick. There is quite a bit of pressure built up in the sump and part of the theory is that this impedes the flow of oil back to the sump so it goes out the top instead.

If there is no more oil as such coming out when at the track I would be keen to fit a proper oil/air seperator or a properly baffled "catch can" and then have the catch can vented to an inlet somewhere so that the is some suction applied to the sump and also nothing going to atmosphere.

Actually its going on the dyno on Friday so this will probably be a good test as last time it also spewed out oil everywhere after a few seconds high speed running under load.

Have you got a drain from the head to the sump? Does it run to a new fitting? As an experiment try disconnecting the drain from the sump and putting it into a temporary container (to see how much if any oil comes out that way) and fitting a breather hose to the inlet/outlet in the sump and running that up to a catch can if you have a spare or just poke it into any vented or open container and see what happens. Have you got restrictors in the oil supply to the head?

yes i have the rear head drain connected though its sharing the fitting on the hot side with the turbo drain. the fitting is screwed into the block so it sits ontop of the oil in the sump.

the best way to test what you are saying would be on a dyno?

not sure of oil restrictors sizes as the motor was built before i brought the car. bit of a guessing game... dont really wanna pull the head now its running so nice.. pinch.gif

also the breathers you have coming out of your sump do the breathers sit at the bottom of the sump (under the oil) or ontop of sump (over the oil)

Edited by BMYHOE

have you heard of anyone fitting a vaccum pump to prevent this?

Yes its been done (probably Google to find examples) - over complication in my view - may as well go to dry sump!

yes i have the rear head drain connected though its sharing the fitting on the hot side with the turbo drain. the fitting is screwed into the block so it sits ontop of the oil in the sump.

the best way to test what you are saying would be on a dyno?

not sure of oil restrictors sizes as the motor was built before i brought the car. bit of a guessing game... dont really wanna pull the head now its running so nice.. pinch.gif

also the breathers you have coming out of your sump do the breathers sit at the bottom of the sump (under the oil) or ontop of sump (over the oil)

Its not recommended to run the head drain into the turbo drain although its an engine out job to put a new drain in the sump (full explanation somewhere in this 40 page thread! http://www.skylinesa..._sk+oil+control

but yes you could try running the drain into a pot of some sort - but with no breather in the sump oil may well be pushed out of that drain - would be interesting to see.

The breathers I have are on the opposite side of the sump from the turbo drain just in front of the driveshaft and (necessarily!!) as high as possible in the sump and above the oil level.

A lot of people still don't put small enough restrictors in with a high output oil pump on an RB30. It won't be a problem on the street but will be on the dyno or track.

since i have changed the setup with the drain back most of the excess oil seems to be draining back into the sump.

though if i hold it though a few gears i'll get around 200mls out of the breather of the catch can.

its alot better then the 2 litres i lost before

have you got an oil pressure gauge? if so whats the oil pressure at ........ also have you done a compression test maybe your rings are a little bit worn prob not if your making big power but still worth a look

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