Kamil D.

if PCV valve use is to remove the pressure from the crankcase WHY THE HECK do we run it beck to the engine why not just put a breather.

why are we mixing oil and polluted air with fresh air in the TB.


if the only point is because its illegal to put these gases directly in the atmosphere??


people spend $ on the oil catch can and other stuff for nothing


also English is not my first language so don’t leave me so stu*pid post abut that

if you smart and know any thing on this subject then post something, don post something stupid or not relevant just because you don’t know any thing.

Thank you,

vettenuts

I find the oil catch can works pretty well with the existing PCV system. The PCV is there because it is a "positive" ventilation system since it draws clean air into the motor and then burns what comes out. I think you will find that a simple ventilation system, were you to check by used oil analysis, would deplete the additive package quicker and you will likely end up with more varnish and build-up within the motor.

Kamil D.

ok so even if it’s a good thing to have the pcv line going out of the crankcase why not just point it down to the ground or in a different place not beck to the TB. Just so the extra gases will still escape from the engine.

or maybe still have the catch can just the part for the TB connect a breather so the gases don’t go to the TB but the fresh air can still go to crankcase

vettenuts

Because the intake vacuum is used to ensure good flow through the crankcase.

Kamil D.

how i really don’t understand it. if you saying that because there is more force of the air coming from your intake then from the empty line from you PCV?

if yes I think your wrong because the engine would suck in all the air and there would be no air going beck to the PCV

I don’t want to argue I just want to understand

thank you for taking you time to help my

k24556

PCV has been around a long time. I think it has been on cars in the US since the 60's. I had a 63 chev impala and I remember it on that car.

http://www.autoshop101.com/forms/h63.pdf This link is a good explanation of how it works. Should similar on a vette.

Now my question. What is the catch pan for? my 2000 'vert has no leaks.

Kamil D.

http://www.conceptualpolymer.com/PCV...oval%20101.pdf

TLewis4095

This is by far the best comprehensive explantaion of how the PCV system works & the mod is done in such a way as to ensure filtered air in & restricted or metered vacum still intact. The only addition to this would be a larger capacity catch can if possible of the same design.

EVERYBODY that is debating this in other threads needs to read this closely!!!!

Oldvetter

GM makes a PCV Valve that is suppose to reduce oil comsumption in V8 Trucks. It was not intended for the LS1, but several other Forums have had people use it on LS1s with good results. GM’s optional small orifice valve part number 12572717 which is just a hollow body PCV valve (without a ball check valve) with a much smaller thru hole in it.

I installed it on mine and an oil analysis proved it had no adverse effects.

Here is a post reporting good results in reducing the amount of oil in the intake manifold:

http://forums.corvetteforum.com/show...Valve+12572717

92mr2turbo

I currently own 2 toyota vehicles. 1 is a 97 lexus es300 with a 3liter v6 motor with 193k miles. The 2nd is my 92 Mr2 turbo 2liter with 240k miles 10k on rebuilt motor. Anyway, I could understand the link posted above for the most part, but Im not 100% sure its necessary.

On the 97 lexus, the pcv valve is working and have been in place since 1997. There is all kinds carbon build up in the back of the throttle body and all inside the intake manifold. Its just black. Car runs perfect.

On the 92, Ive owned almost 7 years it had 112k miles in 01 when I bought it. Being turbocharged all kinds of air is forced into the motor. While modifying it through the years, it has been suggested to reroute the "pcv system" using a "catch can" to prevent oil and carbon build up out of the intercooler piping and intake manifold. Or you could just route the pcv hose to the atmosphere using nothing (what Ive been doing for years). My car came from the factory with no actual pcv valve. There is only a rubber hose coming from the valve cover and is routed to the turbo's inlet rubber piping.

To make a long story short, after routing the pcv hose just to the ground I no longer had oil or carbon build up in my intercooler pipes and intake manifold. I have also added and aftermarket intake manifold and it is still clean inside as the day I intalled it which was about 2 or 3 years ago. My car consumed no oil or had any problems while running this way with over 200k miles.

Since the v6 is not turbocharched and runs fine I have no reason to remove the pcv valve that's still on it. I really believe if i were to install a brand new oem intake manifold on the lexus and not use the pcv valve and route to the line to the atmosphere after 100k miles the intake would be just as clean as my other car.
I know the crankcase needs to be vented but, Id rather have those gases and oil out of my intake tract and engine.

As far as the title of this thread, I think people want catch cans because some want to say they have a catch can or, some people want to comply with the govt, or some people have some issues with their engines causing excessive blow by and actually need a catch can. Even with over 200k miles turbocharched, my motor never had enough blow by to consider a catch can.

This is just my opinion and this is not law.

jovette

Use PCV.............give a hoot, don't pollute!!!!!!!!!!!!!!!!!!!

Speeed-Racer

(I have a catch can, but havent' installed it yet - I am getting it chromed.) I have a catch can so that I can recirculate the unburned hydrocarbons (HC) (read fuel) and other oil additives (all of the helpful gases) without injecting the slimy oil products back into the TB, etc.

For a little light reading...

http://forums.corvetteforum.com/show....php?t=1836888

LT4Justin

How would a breather deplete additives faster? A PCV system applies vacuum to the crankcase and actually sucks gases out while a breather just lets it vent to atmosphere.

Also, how could oil additives even be beneficial when they're either going to sitting in the bottom of a catch can or burned by combustion?


The biggest problem I could see is a basic breather potentially wouldn't be able to release crankcase pressure fast enough and the excess pressure may try to release itself elsewhere (i.e. main seal, dipstick tube, gasket surfaces, etc.) Also, I believe excessive crankcase pressure adversely affects ring seal.

To me, that is the only reason I would consider running a catch can over a breather... Maybe somebody with some extra time on their hands can rig a MAP sensor to read crankcase pressure and do a comparison between a PCV setup and venting to atmosphere.

vettenuts

It would accumulate acids faster because the blow-by will not exit the block as well with just a breather. So rather than being purged and burnt it has more opportunity to condense into the oil. The Total Base Number is the measurement of the acid neutralizing capability of the oil. I think an oil analysis will likely show that the TBN drops much faster on a motor without an operating PCV system (just atmospheric vent) versus a motor that has the PCV correctly operating. I also remember what some of the old motors looked like inside that were just vented, it wasn't pretty but the oils were not as good as today either.

PewtVette

I'll have to agree. Engineering a solution that doesn't contribute to air pollution is the better way to go.

LO PHAT

LO PHAT

thetaxman

anyone check to see if they hurt performance ?
I think that is the case

Dave68

That is not the case unless there is a massive blockage within the filter assembly.

thetaxman

I've heard of many losing ET with a can.
it's not a blockage issue

ZeeOSix

The dirty vapors are sucked out of the engine by the vacuum in the intake manifold. As the engine vapors leave the engine crankcase, new fresh air in flows back in to the engine through the line that runs from the air intake tube (before the throttle valve) and the valve cover(s).

This keeps the dirty vapors out of the inside of the engine by producing a positive air flow through the engine to essentially "wash away" the contaminates due to combustion blow-by at the piston rings.

Before the PCV system was invented, the engine crankcase was just vented to the outside air. It polluted the air, and it also did not evacuate the crankcase very well of harmful deposits, etc.