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What Is an Oil Catch Can, and Why Doesn't Every Car Have One?

immortality

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Done right water/meth works wonders. They make good use of it in the US but you need to tune for it. I've got it for a L67 :)

I'm just working on the PCV system and getting a catch can in there to stop the oil going through the blower first. Already with minor changes the oil consumption seems to have dropped significantly.
 

MACE

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Water Injector FTW, but will save that for another tech post :D (if done properly :p)

This aside,
You do indeed. This kit won't have an intercooler system developed until early 2019. Poor man's alternative ;)
What supercharger kit are you running?

Cheers,
Steve
 

Pollushon

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Hey Steve. Couldn't agree more these kits are pushing upwards of 360rwkw safely on stock. It's by a mob called WASP. An Eaton M122 with a custom manifold and LSA injectors plus all the bits to make it work. Pretty much straight off a Mustang. Designed and commissioned by an ex jet boat racer and engineer out of Melbourne.
 

Mike Litherous

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The fundamental idea of a closed “catch can” is to seperate the oil/vapor mix so that more vapor and less oil make it into the intake. It’s basically a velocity reduction vessel so the heavy oil droplets fall and are returned to the sump.

It’s more of a problem under high rpm loads like in circuit racing. On my BM’s the oil/air seperator stops the plumes of smoke at high rpm. So for normal use it’s prob not an issue hence one is not on my work Ute. If u are spinning the LS engine up over 6000 all the time then it’s prob a good idea or if u have excessive oil in the intake.
 

immortality

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The fundamental idea of a closed “catch can” is to seperate the oil/vapor mix so that more vapor and less oil make it into the intake. It’s basically a velocity reduction vessel so the heavy oil droplets fall and are returned to the sump.

It’s more of a problem under high rpm loads like in circuit racing. On my BM’s the oil/air seperator stops the plumes of smoke at high rpm. So for normal use it’s prob not an issue hence one is not on my work Ute. If u are spinning the LS engine up over 6000 all the time then it’s prob a good idea or if u have excessive oil in the intake.
A catch can is an external vessel that collect the oil and considering that sometimes it's not just oil so ideally you don't want it going back into the sump.

More modern engines are starting to incorporate better oil/air separators into the factory PCV system unlike older engines where the PCV breather is normally only protected by a rudimentary baffle on the end of the rocker cover.
 

07GTS

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A catch can is an external vessel that collect the oil and considering that sometimes it's not just oil so ideally you don't want it going back into the sump.
yep i think most would be amazed at the amount of condensation a cold to operating temp engine makes, just from one warm up i could almost fill a elite catch can with fuely smelling water from the crankcase breather, that's if u only vent to catch if u have it back to vacuum it will go into cylinders so u wont notice it, u don't want that going into the oil
 

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yep i think most would be amazed at the amount of condensation a cold to operating temp engine makes, just from one warm up i could almost fill a elite catch can with fuely smelling water from the crankcase breather, that's if u only vent to catch if u have it back to vacuum it will go into cylinders so u wont notice it, u don't want that going into the oil
But the can is a condensor, the engine is not, at least during normal, operation.
Water vapour is not going to hurt the engine, you can’t stop it anyway, is part of combustion and exposure to atmosphere.
There is no requirement to intervene unless the PCV is ineffective, and or is not port injection. At least no longevity or performance basis apart from coke and soot with DI.
 

immortality

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Condensation in the catch can was the first sign of intake gasket failure on my old VN. Previously only ever had a small amount of oil in it, because the gaskets failing is a slow process looking at the coolant level in the expansion tank didn't give any sign of impending doom. Once the gaskets were replaced it went back to only catching a small amount of oil.

Interestingly enough, it is the PCV system that introduces a lot of the moisture into the crankcase, yes some will come from the combustion process but that will only be a very small %age compared to what flows through the PCV system unless your engine is stuffed and has a huge amount of blow-by. Next time you have the bonnet up and the engine running remove the engine oil filler cap and listen to the revs rise. Any time during high vacuum engine operation a decent amount of air flows through the PCV system.

The function of the PCV system is in the name (positive crankcase ventilation) and it does this by using clean air from the air intake system and as an unintended consequence you get oil vapour through the PCV system as well as the obnoxious blowby gasses the system is designed to remove. There is no reason to want or need any oil in the air intake, the engine does not need it.
 
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Deuce

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Next time you have the bonnet up and the engine running remove the engine oil filler cap and listen to the revs rise.
But what does this rev change mean? Increased revs is released pressure and easier on engine therefore needs bigger breathers?? Drop in revs means vacuum and pcv is working great??

I've seen engines do this before. But I'm pretty sure my 355 does not care if the filler cap is on or off. Revs just sit the same irrespective of cap on/off.
 

immortality

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^^ but it doesn’t hurt it.
Maybe not in the short term but long term?

Like I said before, plenty of evidence on this forum that long term it does cause issues. Maybe more modern engine designs have better PCV systems but certainly not the older generation which includes ecotec/L67, Holden 304 as well as the LS1 engines which are renowned for filling the intake with oil. I've worked on a few engines in my time and I don't much like all the gunk that can accumulate on the intake system. EFI is the saving grace for the PCV system is it effectively washes the intake valve but anything carburated or TBI like my early V8 certainly does not like the oil on the valves.


But what does this rev change mean? Increased revs is released pressure and easier on engine therefore needs bigger breathers?? Drop in revs means vacuum and pcv is working great??

I've seen engines do this before. But I'm pretty sure my 355 does not care if the filler cap is on or off. Revs just sit the same irrespective of cap on/off.
Engine filler cap off effectively creates a vacuum leak (via the PCV system). Yours been MAP tuned it's not quiet so bad but with MAF based systems all of a sudden you are allowing a fair bit of un-metered air into the system.
 

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My combustion chambers after 220k. The carbon buildup was giving me extra compression :)

Whilst the motor ran fine, dumping boost on to this would have probably resulted in tears. Nothing will stop carbon, it's the nature of the beast but oil getting into the chamber exacerbates the issue. Besides the PCV I had some dead valve seals. End result was exhaust valves that wouldn't seal.

All in all not too awful for the kms. I gave the valve on the left a grind just to confirm my theory it could not be saved. EV8 stainless are a better choice for boost anyway.

pic25062017125152097~01~01.jpg


pic25062017125156170.jpg


pic24072017231038511.jpg
 

Pollushon

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@Pollushon that looks disgusting, have you thought about using alcohol (in the car)? I mean eFlex and decent synthetic like GL-5 oil doesn't do that.
Hahaha, funny you should mention that, yes I absolutely will be using alcohol in the form of methanol as part of the water injection kit. I'd convert to straight E85 if I could but Canberra has two bowsers and she's my daily. Apparently after the tune on Thursday my combustion chambers will stay shiny and clean forever more :)

She cleaned up okay
pic02072017145730702.jpg
 

VS_Pete

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@Pollushon that looks disgusting, have you thought about using alcohol (in the car)? I mean eFlex and decent synthetic like GL-5 oil doesn't do that. Same effect with eight (or nine) alky injectors re cooling and knock.
Did you mean Penrite ENVIRO+ GF-5 5W-30?
I`m going to change to the above.
 

07GTS

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i had a issue with a couple valve stem seals going in mine (got pushed up) only found out by removing a spark plug one time and it having oil around it, put a camera into the cylinder and it was blackish where all others from E85 were clean, that also explained the slight difference in 02's bank to bank
 

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Golly gosh.
That looks like more carbon build up than between the legs of the Eurobed old chick.
 
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