Oil catch can

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Postby MAGN1T » Sun Sep 20, 2009 12:26 pm

Jeeze you kiddies got no idea.

New WOF rules mean anyone who's disabled the PCV system won't get one.

BTW the PCV system's purpose is to remove the water and unburnt fuel from the oil. Ricers with catch cans will notice that when they remove the filler cap there's mayonaise inside it. The oil will also probably smell of fuel.
Water and oil don't mix, that's why there's detergent added to motor oil.
Air enters the crankcase via the breather and gets sucked into the intake manifold via the PCV valve along with the water and unburnt fuel. The only time the system stops working properly is when the rings need replacing/motor blown up.

OK kiddies, so why is it such a good idea to disable the PCV system?

Race motors with forged pistons are a different story all together. Forged pistons need greater clearance as they expand a lot more with heat so you'll get a lot of blowby when cold. If there's not enough clearance then when they get hot the pistons will scuff and get stuck resulting in a broken rod. I'm sure everyone has heard at least one horror story of a motor blowing up on the dyno. Combination of a bad tune and insufficient clearance.

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Postby Mr Revhead » Sun Sep 20, 2009 2:18 pm

:roll:

If you had bothered to find out what we're talking about here you would realize the 20v motors are really bad at putting a lot of oil fumes into the intake therefore as Matt mentioned lowering the octane to such an extent that they suffer from excessive octane degradation and quite a lot of carbon build up in the combustion chambers as a result of the burning oil, which leads to more pinking issues, also evident buy the oil usage and smoke from a lot of these cars.

Fitting the system as mentioned totally eliminates those issues resulting in a much nicer running car.

My ae101 is still running like about 100,000ks after I fitted it with nil negative effects. Infact the oil stayed cleaner longer, the car ran better and there was never any of the mayo gunk around the cap. The water you describe was removed by the catch can which I emptied every month or so.

The PCV is purely an emissions thing. What did they used to do before emissions was a concern? Seeing as you keep referring to the rest of the forum as "kiddies" you must surely be ancient enough to remember? Or maybe your at the age where memory, manners and reason start to escape you.....

Where does it state that in the wof rules? I've never heard that one before. If it's true, then yes, it will not be legal.
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Postby Crampy » Sun Sep 20, 2009 2:49 pm

Mr Revhead wrote:The PCV is purely an emissions thing. What did they used to do before emissions was a concern? Seeing as you keep referring to the rest of the forum as "kiddies" you must surely be ancient enough to remember? Or maybe your at the age where memory, manners and reason start to escape you.....


Before the PCV I believe they used a draft pipe, which was simply a pipe that dumped the air/fumes down onto the ground.

At least with a catch can, you are catching the fumes and they recondense into oil fuel and water.
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Postby Lurkin » Sun Sep 20, 2009 3:42 pm

hm ok.

Does anyone know where in the legislation the pcv valve avoidance is illegal?
Do 'normal' catch cans have a baffle/ division of some kind between the inlets and the breather? (otherwise I cannot see any difference between this set up and the 'normal' can - the pressure is connecting at the t, as opposed to in the canm nor the purpose of having the breather on the can as opposed to on the other inlet?)

I realise the 'easy' answer is to mimic a typical catch can - but I don't have the facility to drill and weld it.

Actually none of the joints to the can have been welded. rather they have been drilled, threaded + screwed in?
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Postby Mr Revhead » Sun Sep 20, 2009 3:48 pm

oh sorry i miss read your diagram
yeah, that will work

ideally they do want a division and stuffed with steel wool is also good. you want something to cause the vapour to condense inside the can
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Postby Lurkin » Sun Sep 20, 2009 5:22 pm

Any ideas of what to use to block the pipe holes off?
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Postby MAGN1T » Sun Sep 20, 2009 7:39 pm

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Postby Lurkin » Sun Sep 20, 2009 10:41 pm

Hey Steve

right you are - for a certified vehicle. My cars not certified and does not need to be - the modifications to it are well within the 'allowed' modifications on here:

http://www.lvvta.org.nz/CertThresholdSc ... il04V3.pdf

Thing is, it also allows modifications to the engine on that list provided it does not = 20% increase in power... I wonder if that includes adding a catch can... or is the PCV system considered seperate to the engine?

thank you for identifying this, I do want to keep the entire thing legal.

oh btw I'm not doing this because the engine 'needs' one, ie doesnt have rooted rings on it (ie using the catch can to lower pressure etc) - it was to avoid rubbish going into the intake only.
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