Breathers
Moderator: phpBB2 - Administrators
Breathers
Hello, What does everyone do about engine breathers? I have a 4.0 rover with a holley. Should i have a catch tank or pipe it into inlet somewhere? Any thoughts? should i have the splash plates fitted inside the rockercovers? Thanks.
Hi Paul
as with all things it is a case of depends on your tuning spec and proposed use of the engine.
The basic points are,
Reduced crank case pressure is a good thing as it reduces drag on the crank due to the air in the sump, less air less drag.
The reduced crank case pressure tends to reduce leaks and the oil gets less gunk disolved in it.
The oil mist in the air in the sump, when it is sucked into the inlet and mixed with the fuel air mixture tends to make the engine detonate sooner (it reduces the effective knock resistance of the charge)
If you spend all day in traffic with the engine below 3k revs most deffinatly connect up the crank case breathers to the inlet manifold, your oil will last much longer and therefor your engine.
for fast road use on a warmed up engine but using less than 6.5k revs and 9.5 :1 compression then most definatly use it , I would however put a small catch tank in the line to the inlet manifold and some baffels in it to try and stop some of the oil mist getting to the inlet. It is free power (and worth quite a few)
Drag or race engine on the edge compression wise, no I would only use a catch tank (unless I had a mechanical vacuum pump to use)
I would fit rocker cover baffels
Hope that wasn't too waffely
Mike
as with all things it is a case of depends on your tuning spec and proposed use of the engine.
The basic points are,
Reduced crank case pressure is a good thing as it reduces drag on the crank due to the air in the sump, less air less drag.
The reduced crank case pressure tends to reduce leaks and the oil gets less gunk disolved in it.
The oil mist in the air in the sump, when it is sucked into the inlet and mixed with the fuel air mixture tends to make the engine detonate sooner (it reduces the effective knock resistance of the charge)
If you spend all day in traffic with the engine below 3k revs most deffinatly connect up the crank case breathers to the inlet manifold, your oil will last much longer and therefor your engine.
for fast road use on a warmed up engine but using less than 6.5k revs and 9.5 :1 compression then most definatly use it , I would however put a small catch tank in the line to the inlet manifold and some baffels in it to try and stop some of the oil mist getting to the inlet. It is free power (and worth quite a few)
Drag or race engine on the edge compression wise, no I would only use a catch tank (unless I had a mechanical vacuum pump to use)
I would fit rocker cover baffels
Hope that wasn't too waffely
Mike
poppet valves rule!
Re: Breathers
Paul V8 wrote:Hello, What does everyone do about engine breathers? I have a 4.0 rover with a holley. Should i have a catch tank or pipe it into inlet somewhere? Any thoughts? should i have the splash plates fitted inside the rockercovers? Thanks.
Heres my 2 pence worth! (The setup that I use)
One rocker cover has a PCV valve in it with a pipe that leads to the non ported port of my carb. (The manifold would be just as good).
The other cover has a Chrome mushroom breather but not the type that just pulls in freash air via its crappy filter. Mine has a tube leading from it to the base of the pancake air filter. (A sierra crank case breather tube is a good source of tubing that has loads of bends in it that can be used to make the final tube).
The idea is that if the PCV opens and allows the manifold to pull the air out of the engine the air that replaces it comes via the main intake filter and is therefore properly filtered.
I do have splash guards in both rocker covers.
This is the setup that RealSteel told me to use and it seems to work fine.
HTH,
Pete
I have both splash plates fitted. I removed the filler neck and other bits, then I made some aluminium adapter plates with approx 1" holes in them.
I managed to get a wicked breather system from the states for Sweet-FA; basically a Jaz catch tank with Aeroquip braided hoses, but they came with extra nuts and o-rings so I could just bung them straight on to the adapter plates. Quick, cheap, easy to sort out and looks wicked!
I would post some pics but i have no idea how to do it!
I managed to get a wicked breather system from the states for Sweet-FA; basically a Jaz catch tank with Aeroquip braided hoses, but they came with extra nuts and o-rings so I could just bung them straight on to the adapter plates. Quick, cheap, easy to sort out and looks wicked!
I would post some pics but i have no idea how to do it!
