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Those questioning the exhaust evacuation , you do know it is supposed to be welded to the collector right ? It is the movement of exhaust gases that draws the crank case vapors out at least as I understand it.
So why would this not be a good system ?
It is a very very good system (free HP) when it's conditions are met, next best to using a vacuum pump to draw pressure.
(Hope everyone knows the difference , that a PCV's job is not to draw pressure on the crankcase, but to suck nasty fumes back into the engine to be burned instead of expelled into the atmosphere , at the expense of perfect combustion)
It has to be installed very precise with an open header exhaust (angle and placement of tube), but with any restriction (ie.. back-pressure , or reversion) it's effect is severely diminished or negated.
It is a very very good system (free HP) when it's conditions are met, next best to using a vacuum pump to draw pressure.
(Hope everyone knows the difference , that a PCV's job is not to draw pressure on the crankcase, but to suck nasty fumes back into the engine to be burned instead of expelled into the atmosphere , at the expense of perfect combustion)
It has to be installed very precise with an open header exhaust (angle and placement of tube), but with any restriction (ie.. back-pressure , or reversion) it's effect is severely diminished or negated.
Can you please explain how exhaust being pushed past that angled tube at high speeds stops being effective because of a chambered muffler as I under stand it as exhaust passes the tube it causes a suction which draws crankcase gases out of the motor ..
Those questioning the exhaust evacuation , you do know it is supposed to be welded to the collector right ? It is the movement of exhaust gases that draws the crank case vapors out at least as I understand it.
So why would this not be a good system ?
I haven't ran it, but it sounds like a good system to me
St. Jude Donor '05-'06,'11,'13-'14,'16,'18,'19,'24, '25
unless you've got engine issues your perfectly fine with something close the stock system.
I've the normal PCV valve on one cover and a vented cap on the other with a tube ran to the air cleaner for WOT pulls, very close to the OEM set up. Everything works fine with no signs of oil in the intake nor the air cleaner lib.
No PCV system here either. I use 4 of these (2 on each valve cover) for ventilation. They have a filter type material in the necks. I couldn't justify the cost of the vacuum system or I would have gone with that.
So if I am getting this correct there are some better ways to do this on high performance engines but in my case a mild street 454 I will just fine with breathers in the covers and nix the pvc valve it hurts more than helps...
So if I am getting this correct there are some better ways to do this on high performance engines but in my case a mild street 454 I will just fine with breathers in the covers and nix the pvc valve it hurts more than helps...
The PCV is just dumping dead air back into your intake (and sometimes oil) which can contaminate that nice clean air you are looking for to get the cleanest combustion chamber burn possible. The PCV system is an emissions related item
Last edited by 76Rat; Jan 31, 2015 at 07:01 PM.
Reason: added a line
This is the Moroso air-oil separator system, just plumbed into the line between PCV and a tap on the intake. Handy petcock to drain. Don't know if it catches everything, but there definitely is oil caught by the tank.
Just thinking generally, with valve cover breathers only, the lowest pressure in the crankcase is going to be atmospheric. With a vacuum pump or connection to PCV, pressure is automatically lower, except at WOT with PCV. The tank is a good, not too expensive (approx. $150) solution. IMO. Works for me on 540 anyway.
Last edited by Super6; Feb 1, 2015 at 07:37 AM.
Reason: Just found the bill, corrected price.
unless you've got engine issues your perfectly fine with something close the stock system.
I've the normal PCV valve on one cover and a vented cap on the other with a tube ran to the air cleaner for WOT pulls, very close to the OEM set up. Everything works fine with no signs of oil in the intake nor the air cleaner lib.
It will work without issue,
Neal
I think what I am trying to avoid is oil cake on valve stems and most importantly relieving the down stroke of the pistons to push air out if the crank case. I have seen and had engines with oil damp gasket areas and breathers that seep oil at the grommet. I have also seen dip sticks lifted with high rpm runs.
The PCV although related to emissions is also supposed to evacuate blow by gases which naturally all motors have , but in a high power street motor your need to remove these gases is best served by something that pulls them out.
That is why i posted this topic , to see what others are using. I also think I could run 4 breathers like circle track guys do to allow the down stroke an easy path way to evacuate the gasses .
That's pretty cool, didn't know they had a product like that. I'm gonna have to check those out some.
Also a pvc, header evac or even a vac pump will keep your oil cleaner and reduce leaks, so it's not just about emissions with a pvc.
pvc is more effective if done w/o a breather other wise it's a controlled vac leak that sucks outside air drawn through the engine to the carb. I know some setup are like that from the factory, but it still doesn't make it more effective.
If your getting too much oil from your pvc chances are you got other problems and something like that moroso unit can Band-Aid it. Gasoline itself has some oil residue and some of the additives are a "top end lube". One of the top superstock guys uses a pvc like system, but I can't go into details.
And the header evac not to be used with a muffler I've herd sometimes with backpressure the system can do the opposite. Since I run mufflers and even a manufacturer of a header evac system says not to be used with mufflers that's good enough for me.
Originally Posted by Super6
This is the Moroso air-oil separator system, just plumbed into the line between PCV and a tap on the intake. Handy petcock to drain. Don't know if it catches everything, but there definitely is oil caught by the tank.
Just thinking generally, with valve cover breathers only, the lowest pressure in the crankcase is going to be atmospheric. With a vacuum pump or connection to PCV, pressure is automatically lower, except at WOT with PCV. The tank is a good, not too expensive (approx. $150) solution. IMO. Works for me on 540 anyway.
St. Jude Donor '05-'06,'11,'13-'14,'16,'18,'19,'24, '25
Originally Posted by diehrd
I think what I am trying to avoid is oil cake on valve stems and most importantly relieving the down stroke of the pistons to push air out if the crank case. I have seen and had engines with oil damp gasket areas and breathers that seep oil at the grommet. I have also seen dip sticks lifted with high rpm runs.
The PCV although related to emissions is also supposed to evacuate blow by gases which naturally all motors have , but in a high power street motor your need to remove these gases is best served by something that pulls them out.
That is why i posted this topic , to see what others are using. I also think I could run 4 breathers like circle track guys do to allow the down stroke an easy path way to evacuate the gasses .
Just offering what works for my 700 HP BB 496 driven on the street often which sees 7500 rpms on a regular basis. When the motor is built correctly with attention paid to ring fit and seal you wont have an issue with blow by.
Just offering what works for my 700 HP BB 496 driven on the street often which sees 7500 rpms on a regular basis. When the motor is built correctly with attention paid to ring fit and seal you wont have an issue with blow by.
Neal
You should have a vac pump on a motor like that , you would add up to 40hp..
Can you please explain how exhaust being pushed past that angled tube at high speeds stops being effective because of a chambered muffler as I under stand it as exhaust passes the tube it causes a suction which draws crankcase gases out of the motor ..
My Harley Davidson engine is a simple form of a 327 cu.in. engine. If I place a piece of cardboard at the end of one of the mufflers and apply slight pressure with the engine running to get the carboard to reduce the exhaust flow, the exhaust gas will actually pull/push the cardboard against the exhaust opening in a fluttering motion....this tells me that a muffler that is restrictive can actually cause a millisecond reversal of the exhaust gas between the exhaust valves and the muffler....that would cause reverse flow at times in some header-evac. set-ups from what I see.
