The Manifold I bought for the webers (redline/warneford design) only has a hole in the inlet runner for venturi #6 (rear most), which is fine for the brake booster, but if the PCV is hooked up, it throws the balance of the carbs out (extra air being drawn into the manifold at #6 only).
So I'm trying to work out the best way to hook up the crankcase ventilation.
There is a boss on the inlet manifold at each carb, where a hole could be drilled & tapped, but this still wouldn't be balanced, as the inlet runners on the manifold are completely separate for each venturi on the carby.
Should I drill & Tap EACH of the 6 inlet runners, and connect with a hose so that they remain balanced?
Another way that has been suggested to me is to use the exhaust vaccum....using a valve from a emmision controlled car connected to the exhaust, apparently the vaccum is even higher than from the inlet manifold. The guy who suggested this to me is using this system on his Torana with Webers.
At the all Holden day yesterday, I noticed a lot of cars were running 2 hoses from the top of the rocker cover, to a catch can that had a breather on it - How does this system work? I assume it just relies on the pressure in the engine to vent the crankcase, rather than positively ventilating it with Vaccum?
Crankcase Ventilation with Triple Webers?
Started by
_jklumpp_
, Aug 07 2006 01:58 PM
6 replies to this topic
#2
Tiny
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Posted 07 August 2006 - 03:50 PM
The Catch can setup you mention does exactly that, There's no assistance at all and its also illegal unless its plumbled back in to the air filter to be re-burnt through the carby.
Is it possible just to run a single line from your PCV valve to one of the air filter bases? i agree it woudlnt be assisted as such but it would solve all teh dramas except for the crud going into the carby!
Cheers.
Is it possible just to run a single line from your PCV valve to one of the air filter bases? i agree it woudlnt be assisted as such but it would solve all teh dramas except for the crud going into the carby!
Cheers.
#3
_jklumpp_
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Posted 07 August 2006 - 07:20 PM
Thanks Tiny,
Yes I had thought to attach a pipe into one of the trumpets, and use the 'pre-mixture' vaccum - The catch can would pick up the 'crud', so that wouldn't be a problem, but when i mentioned this to my carby tuner (also the guy with the xu1 using exhaust vaccum) he reckoned it wasn't a good idea, as it would disrupt the airflow into the carb....
Yes I had thought to attach a pipe into one of the trumpets, and use the 'pre-mixture' vaccum - The catch can would pick up the 'crud', so that wouldn't be a problem, but when i mentioned this to my carby tuner (also the guy with the xu1 using exhaust vaccum) he reckoned it wasn't a good idea, as it would disrupt the airflow into the carb....
Edited by jklumpp, 07 August 2006 - 07:21 PM.
#4
FastEHHolden
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Posted 07 August 2006 - 07:51 PM
What year did they stop using the "Hockey Stick" or more correctly , draught tube style of crankcase ventilation? if it was in use on your model you can run a catch can and not run it back to the inlet.
#5
Tiny
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Posted 07 August 2006 - 08:20 PM
I'm not sure wether that's so much of a problem ( the interupted airflow).
With the airflow passsing past the port that has the incoming vented gasses, it would tend to draw those gases into the airstream like a carby i believe. I dont think the interuption would be noticable because the gasses should really be under no pressure themselves?
I may be barking up the wrong tree here but that's what i was thinking!
The other optionis to just use your catch can with filter like alot of others do, and only worry about wehre its vented if worst comes to worst
Cheers!
With the airflow passsing past the port that has the incoming vented gasses, it would tend to draw those gases into the airstream like a carby i believe. I dont think the interuption would be noticable because the gasses should really be under no pressure themselves?
I may be barking up the wrong tree here but that's what i was thinking!
The other optionis to just use your catch can with filter like alot of others do, and only worry about wehre its vented if worst comes to worst
Cheers!
#6
_LoneOranger_
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Posted 07 August 2006 - 11:26 PM
Hi jklumpp,
I use a PCV valve on my Webers and have no real problem.
It is connected to vacuum on the last port.
The trouble you are having is that you have too much vacuum.
The way the PCV works is that when there is a build up of pressure in the crankcase it pushes against the valve and forces it open.
The vacuum assists the gasses down the hose and into the port.
Try using a restictor in the line (small brass or plastic tube sleeve) until you have a small amount of vacuum only.
Mine is set up so if I pull the PCV out of the rocker cover it picks up a tiny bit of speed but still idles OK.
John.
I use a PCV valve on my Webers and have no real problem.
It is connected to vacuum on the last port.
The trouble you are having is that you have too much vacuum.
The way the PCV works is that when there is a build up of pressure in the crankcase it pushes against the valve and forces it open.
The vacuum assists the gasses down the hose and into the port.
Try using a restictor in the line (small brass or plastic tube sleeve) until you have a small amount of vacuum only.
Mine is set up so if I pull the PCV out of the rocker cover it picks up a tiny bit of speed but still idles OK.
John.
#7
_wildsix_
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Posted 09 August 2006 - 07:14 AM
You need to run balancing pipes between each inlet manifold. My friend did this with his xf falcon when he fitted triple webbers. Btw he's an engine builder by trade.
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