what does a stock PCV valve look like?

[jkeyzer]

I have a 1.7 with d-jet, and I think my PCV valve is non stock and is slowly making an oily mess in my engine compartment. Does anyone have a picture of the correct PCV for my engine so I can compare? I wasn't able to find any on the BBS or the PP parts catalog.

Mine has the hose coming in at a right angle to the oil filler and has another smaller stub coming off the valve above (which I think is leaking oil).

Thanks!

[norustscott]

It will be a small brownish plastic gizmo with a white nylon knurled nut holding to the small breatherfiller box. It looks like no other pcv. If you have lots of oil you could be experiencing some additional blow by from an aging engine. just food for thought.

[Dave at Pelican Parts]

Sounds like you might have a 1.8 oil filler neck? That had a hose fitting on it.

Tough to tell from the description, though.

--DD

[jkeyzer]

I saw a similar PCV valve to mine at Pep Boys recently. It is a black plastic piece, with one large fitting on the bottom (goes into the top of the plate that the oil filler is attached to) and two fittings coming off at a right angle - one large one that my breather hose is connected to, and one small one with nothing connected. I'll try to take a picture later tonight.

Are new PCV valves available?

[jkeyzer]

Picture attached...

[Amark]

my 73 2.0 doesn't look like that. The hose comes straight out and there is no second port.

Mark

73 2.0

[Amark]

On second thought you might want to put a rubber plug over that open port. I think you might be sucking un-filtered air into you crankcase. I don't know if that open port is the cause of your oily mess but I don't think it is helping.

The top half of that PCV valve looks like it's the same as a mid 80's GM small block chevy. As long as it fits and it has it's guts I don't think it matters. Inside of a PCV valve is just a one way valve w/ a very light spring holding it closed. The GM type may just have a ball w/ no spring and the weight of the ball holds it closed.

Mark

73 2.o

[jkeyzer]

I took the valve out to inspect and clean it (it was so gummed up it didn't work anyway...) and I have the correct part # valve for the 914. I guess someone just added the right angle piece to make it easier to route the breather line, but didn't plug the second outlet.

Thanks for the pics, now I know what it is supposed to look like!

[Bleyseng]

Some of the cars 1.7 or 2.0 I have seen had that rubber elbow on the PVC valve. (the extra 1.7 I have laying around does)
Usually the rubber boot got hard, cracked and the owner/mechanic threw it away because it was leaking oil everywhere. I would find a good PVC valve (I have one) and just install the hose with a clamp on it.
Geoff

[Will98D]

A PCV valve will be sized for the particular angine and its displacement, so I wouldn't go with the 'Chevy should be OK' advice. The valve designed to 'leak' a certain amount of air in from a 5.7 liter engine will overpower the small 1.7/1.8/2.0

[jkeyzer]

Regardless, I have the correct PCV valve (I checked), it's just the right angle connector that is wrong!

Thanks for all the replies. I'm going to fix the right angle piece and everything should be fine.

[hardflex]

oon my 72 1.7, it's just a simple rubber elbow, without the extra port. that to me looks like the piece the deceleration valve hooks to.

from memory, I want to say the pcv should be closed at idle, opens under less vacuum to let blowby gasses into the manifold to be burned. is that right?

If his valve was stuck, the blowby may have been forcing oil out the extra port, causing the oil slick.

[jkeyzer]

Mine is a 72 1.7 as well. I think the extra opening was allowing oil vapor out onto the engine (as opposed to going to the air box). On the 72 1.7 I don't think the PCV is part of any sort of vacuum system (like the 1.8). Do I even have a deceleration valve? I don't think so.

[Dave at Pelican Parts]

A 72 would have originally come from the factory with a decel valve.

--DD

[pbanders]

I know it's a little late to be adding to this thread, but the photo shows a normal PCV valve that someone has fitted with the "branch tee fitting" that goes onto the plennum. The correct fitting is a rubber elbow that does NOT have a second open port.

You're likely to have a non-functional PCV valve with this open port, and a high idle due to the vacuum leal from the port.

[Dave at Pelican Parts]

Good catch, Brad! I missed that extra part entirely!

--DD

[jkeyzer]

Brad - you're correct on the second port. Someone used a right angle adapter that had two outlets. I plugged the extra one.

However, this did not result in a high idle, just an oil mess everywhere from escaping vapors. The reason is that on my 72, and I'm not sure if this is correct or not, the PCV system does not connect to a manifold vacuum source. Instead, there is a hose that goes up to the air cleaner. My 72 also does not have breather outlets on the heads, so it is a little different than the 73 and later setups I have seen.

Frankly I am glad that my oil filler isn't under vacuum, it's just one more place for air leaks to occur.

[pbanders]

I just reviewed the hose diagrams on the PP site, and while it's not the clearest drawing, it looks like on the 1.7L that the line from the PCV valve goes to the air filter box, so as you say, it's not under vacuum. I guess Porsche should have renamed this valve a "Passive Crankcase Ventilation" system, because it's sure not "Positive"! As you say, no high idle, but an oily mess instead. The 2.0L has the line connected to the plenum, so it's under vacuum. I also went back and check the Porsche Factory Workshop manual, and that's how it shows the 2.0L connection, too.

[pbanders]

FWIW, I have never verified that the PCV valve on a 2.0L D-Jet operates the way that other PCV valves do on other cars. PCV valves have a plunger that's designed to permit only minimal flow at idle vacuum conditions, and permit progressively more flow as engine speeds increase and blowby increases. Clearly, there's no plunger in the D-Jet valve, just a disc. For it to operate similarly, it would need to have not only a stop in the "normal" position (just sitting in your hand - the disc is pushed up against the bottom and the valve is closed), but also a stop in the "top" position (large manifold vacuum pulled on the manifold side - minimal blowby pushing on the crankcase side) to minimize flow at idle condtions. You can't test this by just blowing through the valve, you don't have enough suction/pressure/volume to do it.

Does it really operate this way?

[StratPlayer]

What's the set up on a later model D jet as far as a PVC is concered ie:76