> I don't mean to Flame anyone but....
Don't worry, it doesn't come across that way. You'd have to
call someone a nanosexual melonhumping cheeseball (or something
*really* unpleasant) for it to be taken as a flame... :-)
> The first solution(MGB's '64-'69) is to put a variable
> orifice between the crankcase and the intake manifold
Ah. Right, I've seen those valves, the big diaphragm valves
that sit on top of the intake manifold. Haven't got one.
> The second method (MGB's '70 on) is to put a port into a
> venturi in the carborator (not under the throtle pates!) and
> attach this to the crank case then at idle there is low air flow
> and (from Bernulli's priciple) the presure drop on the port will
> be less that at full throttle where the drop is geater drawing in
> more air from the crankcase.
This is in fact the setup on my car. Remember, that block was
from a '72 and the carbs have the port in the carb venturi, just as
the stock HS4s did that I replaced.
> OOP's now you've conected the PCV from system 1 to a carb in
> system 2 (see above). So now when your a idle the PCV is open and
> the carb is drowing a small amount of crankcase fumes, but when
> the throttle is opened the carb increases its "suction" but the
> PCV thought the throttle was set back to idle and closes its
> orifice allowing less fumes through.
Aha! Interesting. I'll replace -- well, listen:
> If you want to use a PCV with the later MGB you must connect
> the "suction" side of the PCV to the intake manifold and block
> off the crankcase ports of the carbs.
Or you can -- if I read you correctly -- blow off the PCV valve all
together and run the line straight from the cam cover to the carbs,
essentially duplicating system 2. Which is what I want to do, as it
would then work properly with my carbon canister, the vapor return
setup from the carburetors, etc. Then I need a 1/2-to-3/8 reducing
fitting to go between the two differently sized hoses I've got. Lose
the valve, go with straight tubing. Hmmm. Is the tubing size critical
to system performance?
> As far a s I can tell Marcus' PCV system was correct.
Nope. His mechanic had left the hose coming off the crankcase
breather sitting loose on top of the air cleaners. Definitely
not right. That's a sort of bastardization of System 0 (the
vent-it-to-the-atmosphere technique).
It sounds as though Marcus' PCV system simply needs the T to
fit the timing cover vent to the carb fittings, to duplicate
System 2 from your description.
As for me, I'm stopping at Kragen for a reducing fitting tonight.
--Scott
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