PCV?

[doctorpimp]

What about running it back thru the headers?  For a "weekend warrior/performance" street car 
Does it dirty the exhaust/mufflers too much?

[firefighter3931]

What about running it back thru the headers?  For a "weekend warrior/performance" street car 
Does it dirty the exhaust/mufflers too much?

Paul, i've heard mixed results using the header evac system on a full exhaust car. It's designed primarily for a race application with open headers. One instance i heard of was an exploding muffler....this happened because oil pooled in the muffler case and reached it's flashpoint then went kaboom !  This was on a flowmaster chambered style muffler which doesn't flow particularly well...despite the name 

Another guy had good luck using the evac system with full exhaust....but he was using a straight thru style muffler where oil can't pool and collect in the muffler case.

I personally haven't run a header evac system and wouldn't bother with it. A pair of K&N style breathers is fine for crankcase ventilation, inmo.

Ron

[doctorpimp]

Cool.
Thanks Ron

[dodge freak]

For those who would like not to use the pcv and want to go all out and have the best thing to get all the vapors out of the motor ,The Moroso racing vacuum pumps are the way to go. Moroso-22640 for use with a wet sump which most of us have or Moroso-22641 for a dry sump. There is different size pulleys 2.5"-5" so you can match it to your motors rpms. Summit is showing  brackets for chevy and ford motors, not sure if they have Mopars but they should, if not I am sure us motor heads could get one of the brackets to fit. Maybe one day I buy one, but the $400+ price is holding me back.

This is way better than the exhaust way, cause with the right size pulley even at 2000-2500 rpms with little throttle open you will have a strong vacuum sucking the vapors out, and when the throttle is open all the way the strong vacuum will still be there. Leave it to Moroso to do the job right.

[Chryco Psycho]

oil burns far more easily than gas so any oil in the cylinder can create detonation

[grouseman]

oil burns far more easily than gas so any oil in the cylinder can create detonation

[dodge freak]

That I have hear-ed also, but pvc is part throttle not full so its not much of a problem. I have no pinging at all so I add a few oz of oil to my gas after I get some, not always just when I think about it. Of all the carp that has been added to these engines to clean them up the pvc is not bad at all, unless you have a weak motor or is always flooring it for a long time.

[firefighter3931]

Oil contamination in the chamber will cause detonation. On street engines that are pshing the pump gas envelope (compression) this can push them over the edge.

Ron

[original72]

while on the subject of PCV valves and not to hijack the thread.... what could it mean when the hose going from the PCV to the carb pulses.... and i mean noticibly pulses so you can feel it when holding the hose....

Thanks
Bill

[grouseman]

Yeah, I agree with firefighter.  Unburned oil carbon deposits build up in the combustion chamber, and will increase compression.  But that's because oil DOESN'T burn easily.   

[skip68]

I know this is old but, the air coming in from the pcv to the carb is REAL hot.   Can this add to heating up the fuel in the carb and making it burn lean ? ? ?    I'm trying to cool the carb down so I think I'll get rid of the pcv as it's just adding more heat in the carb.   

[mikepmcs]

Ron will tell you not to do that.  Buy a spacer for the carb if you don't already have one. Maybe that will help with temp issues.

Mike

[firefighter3931]

I know this is old but, the air coming in from the pcv to the carb is REAL hot.   Can this add to heating up the fuel in the carb and making it burn lean ? ? ?    I'm trying to cool the carb down so I think I'll get rid of the pcv as it's just adding more heat in the carb.   

Skip, if you eliminate the PCV....make sure to install a breather in it's place. A carb insulating gasket also helps a lot to keep the fuel cooler. Heat transfer from the intake to carb will boil the fuel and make the car run like poop ! 



Ron

[skip68]

I put a 1/2 inch wood/fiberglass spacer under the carb, but I think I need to put a 1" plastic spacer instead.   I will put a breather in place of the pcv.   I don't want any extra heated air intering the engine.   

[green69rt]

After reading through this whole thread I couldn't resist adding a comment.  I just checked out my 2003 Acura and my 2005 Chevy Colorado.  Both have a air line from the crankcase to the intake inlet.  No PCV from the valve cover but the same thing.  I remember my old Nissan pickup had one also because I replace the valve on it.  Anyway, the issues of oil in the inlet air, more heat in the carb, or any other problems are minor compared to manifold-to-carb heat, mixture control, timing, etc.  On a scale of 1-10 this seems like a "1" (low impact.) maybe 1/2.

Finally, I did read somewhere that yes the PCV does vent oil fumes, but for old cars a big reason to have the PVC was to vent gas fumes that make it past the rings and into the crankcase.  This dilutes the oil and we all know that's bad.  Same with water vapor and foaming. 

So unless you need that last 1/2 hp then I would leave the PCV in or find someother way to suck the vapors out.