Another PCV question
Thread Starter
Pro
Joined: Jan 2008
Posts: 616
Likes: 1
From: Huntersville NC
Another PCV question
Can I just remove the PCV valve in this picture and tube the oil fill straight to the front of the carb? If I understand what some of you guys were saying in my last post this valve isn't doing anything for me with were it is located?
Team Owner
Joined: Mar 2003
Posts: 26,118
Likes: 1,874
From: Greenville, Indiana
For a true positive crankcase vent system, you need fresh filtered air in, crankcase vapors out and a system that holds a slight vacuum on the crankcase.
I see the valve that looks like it pulls vapors out but it appears you have a vented oil fill cap. Where's your filtered fresh air in?
You can't just run a straight hose to the carb nipple or you'll have a huge vacuum leak.
I see the valve that looks like it pulls vapors out but it appears you have a vented oil fill cap. Where's your filtered fresh air in?
You can't just run a straight hose to the carb nipple or you'll have a huge vacuum leak.
Thread Starter
Pro
Joined: Jan 2008
Posts: 616
Likes: 1
From: Huntersville NC
For a true positive crankcase vent system, you need fresh filtered air in, crankcase vapors out and a system that holds a slight vacuum on the crankcase.
I see the valve that looks like it pulls vapors out but it appears you have a vented oil fill cap. Where's your filtered fresh air in?
You can't just run a straight hose to the carb nipple or you'll have a huge vacuum leak.
I see the valve that looks like it pulls vapors out but it appears you have a vented oil fill cap. Where's your filtered fresh air in?
You can't just run a straight hose to the carb nipple or you'll have a huge vacuum leak.
I guess I dont have filtered fresh are in. Thought maybe thats what that breather on the fill tube was? Guess I need a non breather tube fill tube cover and a breather somewhere else? I'm not going to mess with my valve covers. What is the consequence of keeping it plumbed the way it, does it cause problems somehow?
Burning Brakes
Joined: Jun 2008
Posts: 1,194
Likes: 13
From: Seattle area, WA (On the Eastside)
If you like the oil fill tube design as I do, then I suggest that you buy a different oil fill tube (I got mine at Corvette Central) that has the tight cap on top rather than the breather cap you have on it now (which I too had), and the PCV nipple off the side of it, and run the PCV valve with an emmissions tubing to the carb. You will still need to get fresh filtered air into the crankcase somehow. This is where people get creative. It may be done by drilling a hole into the intake manifold or even the block, and connecting a hose from there to the air cleaner, or popping holes in those valve covers and using filtered breathers in one or both (see Kensmith's design).
Personally, I bought two C3 valve covers and am using that PCV system instead (PCV in driver side valve cover to carb, and air from cleaner to passenger valve cover). However, I am using a new oil fill tube (sealed cap and plugged nipple) for ease of oil filling and looks. I never did like filling oil in the valve cover hole...too messy for me.
Hope this helps. I got real familiar with this when I got my car!
Personally, I bought two C3 valve covers and am using that PCV system instead (PCV in driver side valve cover to carb, and air from cleaner to passenger valve cover). However, I am using a new oil fill tube (sealed cap and plugged nipple) for ease of oil filling and looks. I never did like filling oil in the valve cover hole...too messy for me.
Hope this helps. I got real familiar with this when I got my car!
Team Owner
Joined: Mar 2003
Posts: 26,118
Likes: 1,874
From: Greenville, Indiana
Mike,
I guess I dont have filtered fresh are in. Thought maybe thats what that breather on the fill tube was? Guess I need a non breather tube fill tube cover and a breather somewhere else? I'm not going to mess with my valve covers. What is the consequence of keeping it plumbed the way it, does it cause problems somehow?
I guess I dont have filtered fresh are in. Thought maybe thats what that breather on the fill tube was? Guess I need a non breather tube fill tube cover and a breather somewhere else? I'm not going to mess with my valve covers. What is the consequence of keeping it plumbed the way it, does it cause problems somehow?
If your picture displays your entire crankcase breathing system, you're falling a little short. All you've accomplished with that is to create a small vacuum leak.
The consequences of not having a properly vented crankcase can be oil leaks, a moisture filled crankcase, acid in the oil, sludge and other contaminants. In no particular order. I wouldn't attempt to quantify how much of each but any of it is bad.
It's not hard to get a working system on your engine.
