Hi,
I am trying to locate a replacement PCV Valve for my 92 LT1. My local O'Reileys has ordered me 2 incorrect valves so far.
I don't have a valve on my engine. Someone replaced it with a bypass elbow? Can someone help me with a P/N or source?
Thanks,

 

I'm assuming it's the same as the one on my '96, which I just picked up from the local Advance Auto Parts for like $2. Just looked up the model and year and bam.

 

It should be AC Delco CV895C. If you are looking at the elbow in the right side valve cover, the PCV valve does not install there, it is in the manifold under the left side fuel rail cover connected to a "U" shaped hose.
The tube and elbow on the right side supplies fresh filtered air to the crankcase from the throttle body.

 

If you're talkin about the local dealer, I wouldn't be surprised. Chimpanzees could do a better job than the retards in the parts department at mine. I found mine at just about any checker or local parts store. They have a catalog for pcv valves for just about every year car let alone c4. Just look up the number and its right there.

 

I had trouble locating mine at first,it's not in the normal location of most SBC

 

Here's what O'Reilly's carrys.... MicroGard - PCV Valve
Part Number: PCV296
Line: MGD
•Mfg. Defect Warranty
•VIN Code: P
Online:
Available

Store:
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Price $1.69 Each
BWD - PCV Valve
Part Number: PCV326
Line: BWD
•Limited Lifetime Warranty
Online:
Available

Store:
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Price $3.99 Each
BWD - PCV Valve
Part Number: PCV486
Line: BWD
•1 Year Limited Warranty
Online:
Available

Store:
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Price $5.99 Each
ACDelco - PCV Valve
Part Number: CV895C
Line: AC
•1 Year Limited Warranty
•Code Cv895c
•1 Vacuum Port
Online:
Available

Store:
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Price $10.49 Each

 

toptechx6,
Why is clean filtered air drawn into the crankcase from the right valve cover?
I appreciate the location of the PCV on the left side of the engine.
Thanks,

 

Hey Ramrod, I do have FSM but don't see any info on proper way to remove the PCV from my 92 LT1, mind giving me some help? The dang FSM doesn't even list PCV in any of the indexes though they have an illustration of it that seems to be incorrect location... thanks in advance!

 

http://en.wikipedia.org/wiki/Crankca...ilation_system

 

ok, it just pulls out right, it's that simple? Oreilly no longer has the AC delco, just the BWD 2 versions, some cheapie version and a Fram, at least per online.

 

Great info from toptechx6 and I found this which is a very informative read on PCV function and problems when it goes south 'due to lack of timely oil changes' according to the author. OReilly no longer carries the AC Delco part, they offer Fram and BWD. BWD has $4 or $6 versions.

autozone has this:
Part Number: PCV1107
Alternate Part Number: PCV1107DL
Features & Benefits
Designed using high-quality components for maximum engine protection. Meets or exceeds all OE requirements.
Part Number: PCV1107
Weight: 0.04 lbs
OEM Brand: AC
Manufacturer: Champion Laboratories, Inc

PCV info:

http://www.tegger.com/hondafaq/pcv-replace/

Replacing the PCV (Positive Crankcase Ventilation) valve, and why you need to
What happens when it gets clogged and how to keep it from getting that way
What happens when you remove it entirely in a modern car?
Replacing the PCV valve
How it works

What happens when it gets clogged and how to keep it from getting that way

Well, to get to the heart of the matter, you need to CHANGE YOUR OIL at timely intervals! That, and that alone, will prevent almost all PCV valve problems. PCV valves plug up with sludge. Sludge is old oil. If you need to change your PCV valve, chances are somebody's not been changing his oil often enough for driving conditions. And chances are good that you'll need to some serious cleaning of lots of other things on the engine, like the throttle body and Idle Air Control Valve.

The system consists of a small air intake breather hose mounted in the intake tract before the throttle body, and the PCV valve, which is typically in the intake manifold or the valve cover. Air flow is from the breather before the throttle body, through the crankcase, up the PCV valve and into the intake manifold after the throttle body. It's basically a controlled air leak, with the PCV valve acting as a one-way check valve that has adjustable flow characteristics.

Some diagrams to help:
http://www.intelab.com/swem/pcv_diagrams.htm

If the PCV valve gets plugged, here's what happens, roughly in order:

Excess crankcase pressure begins to back up the engine's breather tube, into the intake air tube upstream of the throttle body
Engine management system senses absence of air from plugged PCV valve, and adjusts fuel mixture accordingly. Engine makes slightly less power.
Oil begins to be pumped into the air intake tube through the breather hose, upstream of the throttle plate.
Oil runs down the intake tube into the throttle body.
Oil sludges up the throttle body and throttle plate. Gas pedal starts to get sticky. Airflow reduced. Engine management adjusts mixture again. More power loss, possible poor driveability.
Idle Air Control (IAC or EACV) valve gets contaminated and begins to stick.
IAC cannot adjust idle air mixture to compensate for plugged PCV valve. Idle drops, may become erratic as throttle plate cannot close completely.
Oil drips into intake manifold runners. Blue smoke seen out of tailpipe.
Breather tube begins to get constricted from oil contamination and airflow is reduced. Crankcase pressure mounts dramatically.
Oil pushed past valve guide oil seals. More blue smoke.
Dripping on driveway as oil is pushed past seals.

The above is the scenario for a modern car with a feedback engine management system, in other words, one with an oxygen sensor. Older cars without engine management systems were unable to compensate for plugged PCV valves, and the power loss, fuel mileage loss, rough running issues were FAR worse. A PCV valve that was stuck open could even result in a refusal to idle at all.

The function of a PCV valve is to control the flow of crankcase gases. Start your engine, then remove the oil filler cap (watch your clothes; you might get some oil splatters). Place your hand just above the opening. Feel the strong jet of air? That's "blowby", combustion gases that squirt past the piston rings into the crankcase below the pistons. Even new engines in good condition generate lots of blowby (but it's still a small
fraction of what passes through the throttle body).That jet of air has to be vented somewhere, otherwise it will quickly build up pressure inside the engine, and cause those aforementioned very bad things to happen. If the PCV valve gets plugged, blowby pressure has no proper place to go.

The primary reason for plugged PCV valves is neglected oil changes, which causes sludge. Secondarily, it also happens to engines that are primarily used for short trips, where moisture, fuel, and acids build up in the oil, emulsifying it into sludge, which is related to the neglect thing mentioned earlier. 3 months between changes might be too long depending on how you drive.
Also, an engine with worn compression rings will have massive amounts of blowby, which will overwhelm the PCV valve's ability to pass air and cause the excess vapors (and oil) to be pumped into the intake before the throttle plate.

Since the air inside the crankcase also contains contaminants like unburned fuel, water, acids and other things that your engine and its oil do not like, venting the excess pressure also helps to vent those contaminants out of the engine before they settle into the oil in the first place, so your oil stays a bit cleaner longer.

In the old days, you had something called a "road draft tube", which simply allowed the pressure (and the gases) to leak out a hollow tube that extended downwards from the crankcase to a spot near the bottom of the engine, where it dissipated into the surrounding air.

This is a Hudson straight-eight. It has not one, but TWO road draft tubes, indicated by the arrows. The tubes come out of the valve chest just below the manifold and, descend to the bottom of the oil pan.
Hudson Straight-Eight showing draft tubes

There were two problems with this road draft tube system:

When emissions controls first came in, it was recognized that the road draft tube contributed to smog by venting unburned hydrocarbons (raw gas) to the atmosphere
The air inside the crankcase was essentially static except for what was pulled out by suction near the road. If the car wasn't moving, crankcase air flow suffered.

The answer to the emissions problem, first mandated by the State of California around 1960, was Positive Crankcase Ventilation, where the engine was supposed to swallow its own blowby. This meant a closed-loop system: The road draft tube had to go. In place of the road draft tube was the famous PCV valve.

Some PCV valves are very simple to replace. They sit on top of the cam cover, right in plain sight. You grab them, haul until they pop loose, then replace them.

 

Hello to all,


I just replaced the air filter in my 92 vette, it went relatively smoot considering a few cuts and scraps.
My question at this time is how do you remove the fuel rail in order to replace the pcv valve. Does it just snap out or are there some screws somewhere within the rail it self. I know I have to be gentle with it so it doesn't chip or crack.
Any responses would ne appreciated


Polo92

 

I don't think you need to remove the fuel rail.



I believe it's at the end of the U shaped hose in the center of this pic.