pics
06-17-2005, 05:48 PM
#11
Former Moderator
After further review, Amy's pic has the tank plumbed in the fresh air inlet line. Much oil shouldn't be collecting this way, As this is a air "in" line, not out.
The only time the front breather will have crankcase pressure flowing into the engine is a WOT, or zero engine vacuum.
Most all of the JDM plumbed tanks use both the PCV valve line, (with valve still in) and the front breather line to a common tank. If the tank is not vented (the Cusco is not) crankcase pressure will build up in the crankcase and tank. If the tank is vented, the crankcase pressure will be vented through the tank.
The PCV valve is designed to be opened by vacuum from the intake manifold. Without this vacuum source, you are relying on and positive crank case pressure to open the valve. PCV valves are not precision made check valves, the don't seal perfectly, nor are the designed to backwards flow.
The advantage to using the tank in the PCV line is you are still using engine vacuum to evacuate crankcase pressure. The crankcase can't be completely sealed. If it is, a positive crankcase pressure can blow out gaskets and seals from the inside.
At the end of the combustion stroke, unburned fuel and small amounts of water vapor leak past the rings. If the water condenses after the engine is shut of, the oil breaks down and forms sludge. Unburned fuel also dilutes the oil.
I've never pulled more than a few teaspoons of oil from my catch tank every 2500 miles, for street use. The amount goes up on track days.
I would prefer to use the PCV sytem to ensure the crankcase is evacuated.
The only time the front breather will have crankcase pressure flowing into the engine is a WOT, or zero engine vacuum.
Most all of the JDM plumbed tanks use both the PCV valve line, (with valve still in) and the front breather line to a common tank. If the tank is not vented (the Cusco is not) crankcase pressure will build up in the crankcase and tank. If the tank is vented, the crankcase pressure will be vented through the tank.
The PCV valve is designed to be opened by vacuum from the intake manifold. Without this vacuum source, you are relying on and positive crank case pressure to open the valve. PCV valves are not precision made check valves, the don't seal perfectly, nor are the designed to backwards flow.
The advantage to using the tank in the PCV line is you are still using engine vacuum to evacuate crankcase pressure. The crankcase can't be completely sealed. If it is, a positive crankcase pressure can blow out gaskets and seals from the inside.
At the end of the combustion stroke, unburned fuel and small amounts of water vapor leak past the rings. If the water condenses after the engine is shut of, the oil breaks down and forms sludge. Unburned fuel also dilutes the oil.
I've never pulled more than a few teaspoons of oil from my catch tank every 2500 miles, for street use. The amount goes up on track days.
I would prefer to use the PCV sytem to ensure the crankcase is evacuated.
06-17-2005, 06:18 PM
#12
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Originally Posted by Slows2k,Jun 17 2005, 05:48 PM
After further review, Amy's pic has the tank plumbed in the fresh air inlet line. Much oil shouldn't be collecting this way, As this is a air "in" line, not out.
The only time the front breather will have crankcase pressure flowing into the engine is a WOT, or zero engine vacuum.
Most all of the JDM plumbed tanks use both the PCV valve line, (with valve still in) and the front breather line to a common tank. If the tank is not vented (the Cusco is not) crankcase pressure will build up in the crankcase and tank. If the tank is vented, the crankcase pressure will be vented through the tank.
The PCV valve is designed to be opened by vacuum from the intake manifold. Without this vacuum source, you are relying on and positive crank case pressure to open the valve. PCV valves are not precision made check valves, the don't seal perfectly, nor are the designed to backwards flow.
The advantage to using the tank in the PCV line is you are still using engine vacuum to evacuate crankcase pressure. The crankcase can't be completely sealed. If it is, a positive crankcase pressure can blow out gaskets and seals from the inside.
At the end of the combustion stroke, unburned fuel and small amounts of water vapor leak past the rings. If the water condenses after the engine is shut of, the oil breaks down and forms sludge. Unburned fuel also dilutes the oil.
I've never pulled more than a few teaspoons of oil from my catch tank every 2500 miles, for street use. The amount goes up on track days.
I would prefer to use the PCV sytem to ensure the crankcase is evacuated.
The only time the front breather will have crankcase pressure flowing into the engine is a WOT, or zero engine vacuum.
Most all of the JDM plumbed tanks use both the PCV valve line, (with valve still in) and the front breather line to a common tank. If the tank is not vented (the Cusco is not) crankcase pressure will build up in the crankcase and tank. If the tank is vented, the crankcase pressure will be vented through the tank.
The PCV valve is designed to be opened by vacuum from the intake manifold. Without this vacuum source, you are relying on and positive crank case pressure to open the valve. PCV valves are not precision made check valves, the don't seal perfectly, nor are the designed to backwards flow.
The advantage to using the tank in the PCV line is you are still using engine vacuum to evacuate crankcase pressure. The crankcase can't be completely sealed. If it is, a positive crankcase pressure can blow out gaskets and seals from the inside.
At the end of the combustion stroke, unburned fuel and small amounts of water vapor leak past the rings. If the water condenses after the engine is shut of, the oil breaks down and forms sludge. Unburned fuel also dilutes the oil.
I've never pulled more than a few teaspoons of oil from my catch tank every 2500 miles, for street use. The amount goes up on track days.
I would prefer to use the PCV sytem to ensure the crankcase is evacuated.
06-17-2005, 06:22 PM
#13
Former Moderator
You can run the hose from the front valve cover breather to the SC inlet tube, just take the tank out. I would move the Cusco tank's hoses to the PCV line. If you run a little filter on the front breather you will have some oil that is pushed past the filter dirtying things up.
, i learn something new everyday. Thanks again as always. u the man!
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