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Location:
Sydney
Registered:
January 2004
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Location:
NSW, East Coast
Registered:
July 2003
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Re: Blowby and 4AGE compression
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Thu, 22 January 2004 14:14
 
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I have the same delima with my bluetop.
But mine isnt blow by, mine is vacumm cause by the inlet manifold sucking more air thru the pcv then there is causing a vacumm.
When i take my oil cap off i have what i thought was pressure build up (caused by acess blow-by or blown h/gasket)but its the complete oposite.
Remove your pcv hoses then take off the oil cap and see what it does.
Why it is like this i dont know, but im going to find out, wether someone tells me or i figure it out by myself.
Im treading lightly as i know someone who just lost their dip stick down the hole, not a very nice sound, and ill bet my left nut it was caused by to much vacumm,
Perhaps someone can shed some light on the subject.
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Location:
Sydney
Registered:
January 2004
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Re: Blowby and 4AGE compression
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Thu, 22 January 2004 23:29
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There is only one pcv hose isnt there, i took that one off, but there is still a lot of air, maybe mine is a diff prob to yours. My dipstick was harder to get out though when the car was running... do you think mine really is blowby? Wouldnt the comp be down if you were getting a lot of blowby?
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Location:
Brisbane
Registered:
February 2003
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Re: Blowby and 4AGE compression
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Fri, 23 January 2004 00:08
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sorry if this is wordy, and if you know all this please ignore...
pcv valves should only open up when there's high vacuum in the intake manifold - constant vacuum in the crankcase suggests that the valve is stuck open or has been removed from line.
an old-style crank ventilation system needs two pipes
-one sees atmosphere (usually from inside the air filter) and feeds air into the case unless there's excessive blowby, where it will then vent it into air cleaner
- second extracts air from the case only via the manifold (after the TB), and only when there's high vacuum (cruisin or deccel). valve is matched to the air-flow and operating vacuum of the motor
you really need these two (or similar) working otherwise the crase will be:
-in vacuum (if the atmo pipe is closed off) unless engine is being boosted or accelled hard - where the case will be pressuring when the motor is under greatest stress
-in pressure (if the vacuum is not working) then the seals/gaskets will fail plus rings will have excess oil around them during combustion so there might be eventual carbon/crap buildup in ring lands.
a standard motor at idle should let you place a light card over the oil filler hole and it should alternate between blowing the card off the hole and then sucking it down. that;s what you have to aim for in setting up any vent system.
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Location:
NSW, East Coast
Registered:
July 2003
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Location:
NSW, East Coast
Registered:
July 2003
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Re: Blowby and 4AGE compression
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Fri, 23 January 2004 03:50
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Actually i do follow know.
I have the pcv connected the the inlet manifold, but why does it create such a high vacumm. If i leave it on and i drive i get a squeeling noise, sort of sounds like a train on the railway tracks coming from the back of the motor.
But when i take of the hose squealing stops?
This has got me stuffed.
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Location:
Brisbane
Registered:
February 2003
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Re: Blowby and 4AGE compression
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Fri, 23 January 2004 05:27
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| FKN16V wrote on Fri, 23 January 2004 13:43 |
I would suspect that if it was blow-by then compression would be low.
I still have a fair amount of air pulsating out of the oils cap. I can suck and blow air (yukky) thru the pcv when the motor is off, does this mean there is something wrong with the pcv.
thechuckster wrote
- second extracts air from the case only via the manifold (after the TB), and only when there's high vacuum (cruisin or deccel). valve is matched to the air-flow and operating vacuum of the motor
Im not following properly? But then again i am quite tired at the moment.
Is there pics available of where you say about the t/b.
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hi steve,
the PCV valve should only work one way - tho when the spring/seal in them gets loose from age/heat, you can blow back thru them slightly.
sounds like yours is stuffed - also they only work as designed one way...
squeal is probably the intake sucking huge amount of air thru the valve.
it needs the high vacuum to scavange unburnt furl vapour and oil vapour form the ase so it can burn it rather than have it pollute the oil.
i'll find a drawing in my nearly-useless Haynes celica manual and post it up later today? it sort of shows you how it works and why.
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Location:
Brisbane
Registered:
February 2003
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Location:
Melbourne
Registered:
May 2003
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Re: Blowby and 4AGE compression
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Fri, 23 January 2004 11:07
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shite! i never realised that other people were having this problem...actually i didnt even realise that this was a problem. ive always had gas escaping out of the oil filler at pretty high pressure with the motor at idle, but i thought that it was just a characteristic of the 4ag.
(hehe, i still remember when my mate tried to pour oil in with the motor running, the stuff got sprayed out all over the engine bay  )
so whats the verdict? is it due to my pcv valve being blocked?
and also, where does the recirculation hose enter the intake on the 4ag??
thanks guys
====cheers, roman===============================
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Location:
Sydney
Registered:
January 2004
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Re: Blowby and 4AGE compression
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Fri, 23 January 2004 12:04
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Yeah - I'm not sure whether we've figured out that this is a problem or just one of those things. My PCV valve doesn't seem to be blocked - atleast the one leading to the intake. Steve (FKN) seems in need of a bit of attention with the squeeling and shit.
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Location:
NSW, East Coast
Registered:
July 2003
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Re: Blowby and 4AGE compression
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Sat, 24 January 2004 01:56
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Ive installed a oil catch can, and blocked off the hole in the inlet manifold. No dramas yet.
It was pissing down rain most of last night, so what do you do when its wet, practice drifting, gave the motor heaps of curry too and it didnt miss a beat.
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Location:
Melbourne
Registered:
May 2003
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Re: Blowby and 4AGE compression
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Mon, 09 February 2004 05:24
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i dont think the 4ag has a pcv valve as such..
cos the rubber hose between the rockercover and the inlet has no valve in it, unless the valve mechanism is in the top of the actual rockercover. ive has a looksee but all i can see is a lot of ribs and stuff and its hard to work out whats going on underneath them all seeing as theyre popriveted on..
so whats the verdict? is this blowby? is it a problem?
i;ve actually seen a couple of cars and what they do is run a thick inlet/outlet carbi fuel filter which acts like an oil catch can, but will only set you back about $12 from autobarn...from memory its the z14 filter (the same ones that are run in the xy 351 cleveland)
sounds like a good idea cos i dont want oily shite going back into my inlet 
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