[urq] Too much Crankcase ventalation?
vegener at post7.tele.dk
Wed Sep 5 03:04:22 EDT 2007
I would love if it was that easy -
Just now I am battling with too much oil in the catch tank.
My block is a WR 83 w/o the lower crankcase breather system connection (came
in 84 ).
I have placed a 3B 20V head and on top an ADU valvecover with plugs on coil.
This valve cover have an external oil returnline (I have realized now) and
are just making it working that way.
There is not much room inside the valvecover to find a place, where the cams
are not splashing oil and a strong accelerations
- high revs - the valvecover simply gets full of oil.
I have apparently a weak clutch (034EFI 800 Nm) and a 1/4mile where most of
the 12 sec are at the rev limiter 7800 rpm
can pump 3/4 litre of oil out. (not supposed to 7800 rpm but that happens)
I have a small returnline to the aux oil resorvoir at the 3B pan from a
Vortex air/oil separator but not big enough.
Urq-83 20V 525Hp
200 20V Avant 280Hp
----- Original Message -----
From: <QSHIPQ at aol.com>
To: <quattro at audifans.com>; <urq at audifans.com>
Cc: <Djdawson2 at aol.com>; <benswann at comcast.net>
Sent: Wednesday, September 05, 2007 4:59 AM
Subject: Re: [urq] Too much Crankcase ventalation?
> A proper crankcase>valve cover oil vapor PCV system, won't suck oil,
> shouldn't enough vacuum to do so. IME, oil from launches is a problem
> to the v8's and S cars with the PCV breather hoses at the back of the
> PCV pickup and/or vent should be dead center in a cam cover to avoid the
> launch and hard braking sloshing of oil. The reason for a tie-in of the
> crankcase ventilation with the valve cover, is exactly to act as a
> dead-air oil
> return chamber for crankcase oil. IMO, the 5k's with the double walled
> cover had a better design for PCV than either the later flagship v8's or
> Regardless, the urq has the same basic system as the 5k's, without the
> problem of oil sloshing. Ben's issue is strictly too much vacuum IMO.
> To fix the
> S-car or v8 problem of oil sloshing in the valve cover, it should be
> easy to install a traditional ball type PCV valve and gasket dead center
> the valve cover, with the vent line placed on top too.
> In a message dated 9/4/2007 8:58:00 P.M. Central Daylight Time, Djdawson2
> I would agree that the noise you are hearing is air being sucked past
> Idle = high vacuum = noise. Revs higher = low/no vacuum = no noise.
> I guess recirculating crankcase gasses is an option, but I don't see it
> as a
> requirement. A catch-can is an OK solution, but if you use the car
> aggressively, it will fill fast.
> Even an AAN engine, with its windage tray, will push a very large amount
> oil through the breather system during an aggressive launch. No good.
> I don't know if I'd want to make a project out of properly sizing the
> breather system. To me, a good solution involves a breather device that
> allows the
> oil to return to the crankcase.
> If you've built an engine with serious performance potential in mind, no
> matter how good the system works, you're going to be pushing a lot of oil
> through it... not just gasses. To me it was only important to properly
> vent the
> crankcase, and return the out of control oil flow back to where it
> the pan.
> Unless you redesign around some of the limitations inherent in the stock
> supply system, I think that a PCV approach will always leave you with oil
> places that you don't want it... FWIW.
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