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Discussion Starter · #1 ·
I was wondering if anyone here has a drain back to their oil pan from their catch tank. That way you keep the necessary oil in the pan. I'm think of plumbing up my tank this way, just not sure if its wise or not. Does anyone here do this or have any advice on why not to?

Thanks
Mitch
 

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The proper way to do it is to use an oil separator that swirls the oil out of the air/water vapour and returns it to tank whilst the rest of the blowby products end up in the catch tank.

Take a look at a picture of the underbonnet of a Group A R32 Japanese Touring Car and you will see a really nice system. As far as I know no one has ever sold a similar system. The last thing you want in a 1000km endurance race is to store any vented oil in the catch tank.
 

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i think this is a really bad idea to drain the catch tank into the sump ....
every 2000km or so i have to drain my catch tank it's full of water from condensation out of the engine and almost no oil residue what so ever
so the last thing i would want to do would be to drain water into my sump ..
 

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Discussion Starter · #4 ·
Ok, so then is it better to run a catch tank or a nismo oil/water separator. The separator atleast you don't need to empty and it returns the oil.

If you had only the option to run just the catch tank or oil separator what would you run?the catch tank I'm looking at is only marginally cheaper then the separator.
 

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i just run a catch tank like i said i really don't see any oil in the tank only water
so in my case there would be nothing to seperate
if your engine is in good condtion you also should see very little or no oil in the tank only water by the way catch tanks are not expensive i paid about £25 for mine you don't need to spend hundreds on a tank ..for what
maybe in a racing situation running high boost levels for prolonged lengths of time more oil would be blown out of the breathers this is maybe why they used oil seperators in the japanese touring r32's
 

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Exactly, if you are seeing anything other than oil vapour, your engines not right ....
Most catch cans were originally required as a method to catch oil for track cars so they dont spit oil onto the track but they have become a popular "fill the engine bay with bling" thing ....
Sure theres excetions to this but I would never vent or return one back to an engine.
 

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We do it all the time and its been fine in street cars or race cars, never had a problem with oil contamination or oil needing changing real regularly or anything.

I think the tiny amount there is with an engine that is in good condition is soon taken care of by heat in the engine if any makes it back to the sump.

Rob
 

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Discussion Starter · #8 ·
Hey RIPS,

I'm guessing the drain is above the fill line, but also do you drain to the exhaust side or the intake side?
 

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Return to sump is absolutely fine. If you are on track you really do not want to spill oil on track nor do you want it all over your glowing hot exhaust to set your engine a light. If your engine is good, you wil get some oil in the tank and thats it. No issues draining it back to the sump at all. You dont want oil in your intake either.....
 

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i run mine back to the sump.i have a smooth torque performance tank on mine, it has a drain at the bottom,then about an inch up from that there is the drain to sump. the 2 pipes are seperated by a baffle. so when i drain mine there is water in the bottom section, the oil is kept seperate from the water, water is heavier than oil, so it sinks through the oil to the bottom the baffle stops the oil mixing with the water. the bottom section holds about a litre of water, so in winter i drain it about once a fortnight, in summer its fine, as rob says the heat of the motor drys it out. on track my 30 can put 2-3 litres of oil through it, but as it goes back to sump its fine, lets face it on track the oil in the tank is the same as in the sump when hot. on the road the car puts no oil in the tank at all. the tank has a screw cap to allow you to look inside to see whats happening inside.no issue...bernie
 

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I have a RIPs catch tank plumbeb back into the sump. So far I've not had any oil or water in the catch tank only vapour which is vented via the 2 filters on the catch tank. Thats what the system is supposed to do isn't it.
 

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same as me - i have the rips sump which has 2 fittings that run from my catch can back to the sump

if rob says its the way to do it then im on his side :)
 

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Bringing up an old thread....
There seems to be mixed veiws on feeding the catch can back into the sump,

Surely the oil returning from the catch can is contaminated? Good synthetic oil is dear as poison....and mixing some blowby back into it?

Enlighten me
 

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Its not contaminated with anything that will hurt the oil, only thing guys see in a catch tank that is NOT returning to the sump is milky sludge from moisture and presume its bad but its only because its been allowed to gather.

Whats comming out the breather hoses that your worried about?? Oil vapor, air, some combustion fumes and when cold a little moisture maybe.

Air and fumes go out the breather fllters, air/oil is seperated by the baffling etc and just oil returns. When cold any slight amount of moisture in the oil quickly evaporates, goes back out the hose and then vents.

If you don't return the oil, I presume you'll just dump the oil (thats as dear as poison) thats collected in the catch tank?

Rob
 

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Its not contaminated with anything that will hurt the oil, only thing guys see in a catch tank that is NOT returning to the sump is milky sludge from moisture and presume its bad but its only because its been allowed to gather.

Whats comming out the breather hoses that your worried about?? Oil vapor, air, some combustion fumes and when cold a little moisture maybe.

Air and fumes go out the breather fllters, air/oil is seperated by the baffling etc and just oil returns. When cold any slight amount of moisture in the oil quickly evaporates, goes back out the hose and then vents.

If you don't return the oil, I presume you'll just dump the oil (thats as dear as poison) thats collected in the catch tank?

Rob
In fairness with the old engine, All I had in the catch can was 90% water (Smelled a bit like gas) and 10% oily sludge, I had a hose coming off each cam cover and a filter on the can, I later removed the filter and ran a hose to the back of the car to get rid of the smell.
The water in my tank never evaporated, I had to empty it about every two weeks....I wouldn't want to put that back in the motor.

How does the baffle work/look like to separate the water from the oil, And how do you know you are only putting oil back in the sump

I'm just not sure how heavy the new motor will breath, And probably going to be running more boost etc, So the small catch can I have may not be good/big enough.
 

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The water in my tank never evaporated, I had to empty it about every two weeks....I wouldn't want to put that back in the motor.
Of course it would never evaporate, its not exposed to enough heat.

What you saw was the result of alot of running and collecting the vapour/water and of course you wouldn't want to pour all that water straight in the sump.

With a return the water can never accumulate, there's a tiny amount at any one time, it gets hot, turns to vapour and goes out the catch tank breathers, the oil stays clean, during a good thrashing you don't run the risk of having a liter or 2 of oil in a catch tank that should be in the sump and its a maintainence free system.

And thats just some of the advantages.

Rob
 

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In fairness with the old engine, All I had in the catch can was 90% water (Smelled a bit like gas) and 10% oily sludge, I had a hose coming off each cam cover and a filter on the can, I later removed the filter and ran a hose to the back of the car to get rid of the smell.
The water in my tank never evaporated, I had to empty it about every two weeks....I wouldn't want to put that back in the motor.

How does the baffle work/look like to separate the water from the oil, And how do you know you are only putting oil back in the sump

I'm just not sure how heavy the new motor will breath, And probably going to be running more boost etc, So the small catch can I have may not be good/big enough.
My current gtr with rb26 has a catch can which doesn't drain back into the sump, this catch can was designed and fitted by croydon racing developments (crd) here in syd & it also had a hose fitted which vents to the back of the car.

with my rb30 & rips sump with catch can drained back into the sump, I never had to worry about oil level running low which was piece of mind.

I guess every workshop has their own philosophy :)
Obviously, both above mentioned gtr specialists are the best in the game!
 

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with my rb30 & rips sump with catch can drained back into the sump, I never had to worry about oil level running low which was piece of mind.
Just to confirm for sub boy, your oil changes are still at normal intervals and it doesn't get "milky"?

Rob
 
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