Crankcase Evacuation System question ?
Thread Starter
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Crankcase Evacuation System question ?
My new Race Demon carb does not come with many vacuum ports, as a matter of fact it has none. I already tapped my Vic. Jr. intake for a vacuum port for my brakes and headlights and was going to run the PCV into the air cleaner assembly. Now I did this on my old motor and the "suction" just wasn't enough to keep oil off the valve covers so I was thinking about running a Crankcase Evacuation System. Mr. gakset sells one for pretty cheap, it comes with "breathers" for both valve covers and check valves and 3-1/2'' long threaded tubes that have to welded in to the headers. I would only use 1 of these and let the "suction" from the header pipe work the PCV system like vacuum from the intake did before, I am not trying to change the pressure in the crankcase for better ring sealing etc. just trying to clear the gasses out.
Any comments on the idea, good or bad ?
Any comments on the idea, good or bad ?
Race Director
Joined: Nov 1999
Posts: 10,643
Likes: 8
From: Foxfield CO 1970 Convertible
Since you aren't worried about emissions, why don't you just install some breather caps with baffles on your valve covers and be done with it? Your engine is pretty new, (right?) so you can't have a lot of blow-by...
Team Owner
Joined: Feb 2003
Posts: 30,183
Likes: 313
From: Lake Norman NC
Originally Posted by Z-man
Since you aren't worried about emissions, why don't you just install some breather caps with baffles on your valve covers and be done with it? Your engine is pretty new, (right?) so you can't have a lot of blow-by...
Safety Car
Joined: Aug 2000
Posts: 3,711
Likes: 43
From: San Antonio TX
Aspiration tubes will work on a street engine as long as you have enough gas velocity(backpressure doesn't affect how they work. It's strictly velocity). Trick is that you don't see the velocity until the rpm comes up. I wouldn't do it unless it was my last resort. I'd rather run a PCV since it pulls most at idle.
Race Director
Joined: Oct 2000
Posts: 15,048
Likes: 79
From: central FL, near the beach.
Originally Posted by MotorHead
My new Race Demon carb does not come with many vacuum ports, as a matter of fact it has none. I already tapped my Vic. Jr. intake for a vacuum port for my brakes and headlights and was going to run the PCV into the air cleaner assembly. Now I did this on my old motor and the "suction" just wasn't enough to keep oil off the valve covers so I was thinking about running a Crankcase Evacuation System. Mr. gakset sells one for pretty cheap, it comes with "breathers" for both valve covers and check valves and 3-1/2'' long threaded tubes that have to welded in to the headers. I would only use 1 of these and let the "suction" from the header pipe work the PCV system like vacuum from the intake did before, I am not trying to change the pressure in the crankcase for better ring sealing etc. just trying to clear the gasses out.
Any comments on the idea, good or bad ?
Any comments on the idea, good or bad ?
Le Mans Master
Joined: Apr 2000
Posts: 5,202
Likes: 10
From: cincinnati ohio
St. Jude Donor '09
Originally Posted by gerry72
Aspiration tubes will work on a street engine as long as you have enough gas velocity(backpressure doesn't affect how they work. It's strictly velocity). Trick is that you don't see the velocity until the rpm comes up. I wouldn't do it unless it was my last resort. I'd rather run a PCV since it pulls most at idle.
If you have the hood clearance you could run a carb spacer with an added vacuum port.
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
This is a 3/8th brass for my pvc right out of the back of the manifold.
I think you should buy a belt driven evacuation kit. They are less than $400 and they work great.
I think you should buy a belt driven evacuation kit. They are less than $400 and they work great.
Thread Starter
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Yup that's where mine is, I wonder where I got the idea ? 
Hmmm belt driven evac system, who makes one. I was actually thinking of
some kind of small electric motor fan inside the hose, I just want to get rid of fumes
Hmmm belt driven evac system, who makes one. I was actually thinking of
some kind of small electric motor fan inside the hose, I just want to get rid of fumes
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Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Originally Posted by MotorHead
Yup that's where mine is, I wonder where I got the idea ?
Hmmm belt driven evac system, who makes one. I was actually thinking of
some kind of small electric motor fan inside the hose, I just want to get rid of fumes
Hmmm belt driven evac system, who makes one. I was actually thinking of
some kind of small electric motor fan inside the hose, I just want to get rid of fumes
The vaccuum pumps and mounts are only about $20 per HP. It's real bargain.
http://www.jegs.com/cgi-bin/ncommerc...61&prmenbr=361
