351w PCV valve and oil and sound?

slickmainer · Post by **slickmainer** » July 20, 2011, 7:12 pm

I know nothing about this so bare with me. this looks like the valve I have

1)Oil will gather where the black plastic meets the metal
2)there is, what I would call an air blow by sound when you move the base around, is that to be expected
3)the hose that is at the top goes to my transmission and this also makes a sound when you pinch it, but that could be by design, i dont know.
4)im wondering if this is related to my transmission not shifting correctly, like there isn't enough pressure.
5)once the engine is off, I can pull out the pcv and it will rattle, i think that is right?

I know I probably have all the directional air flows wrong and said pressure when it's a vacuum or vice verse.

any thoughts?
I read where blow by at the pcv might mean a cylinder ring gone bad

ezernut9mm · Post by **ezernut9mm** » July 20, 2011, 8:22 pm

the auto in my 67 gets it's vacuum straight out of the intake. i'm not sure, but i don't think manifold vacuum is the same as crankcase pressure.
but maybe those types of valves are intended to operate like they are manifold vacuum.
it doesn't seem right to me gregg.

slickmainer · Post by **slickmainer** » July 20, 2011, 8:33 pm

the bottom hose goes to the intake manifold

I think this is a 73 or 74 block and 2v intake

62galxe · Post by **62galxe** » July 20, 2011, 8:55 pm

you want manifold vacuum to the trans.

banjopicker66 · Post by **banjopicker66** » July 20, 2011, 8:57 pm

1)Oil will gather where the black plastic meets the metal
Some oil is probably OK, but it may indicate blowby. More info is needed, probably after you make some changes I suggest, below. You are correct about the vacuum being off at the PCV valve.

2)there is, what I would call an air blow by sound when you move the base around, is that to be expected
Possibly, I assume you mean the base of the PCV valve?

3)the hose that is at the top goes to my transmission and this also makes a sound when you pinch it, but that could be by design, i dont know.
4)im wondering if this is related to my transmission not shifting correctly, like there isn't enough pressure.
This is setup incorrectly, especially if it is a C-6 transmission. Your transmission should be pulling manifold vacuum directly off the back of the intake. Yes, my guess is this is causing shift problems, due to the vacuum at the PCV valve being different that what the transmission needs.
There should be some kind of vacuum tree on the intake, in the back. Try attaching the transmission line to this, and see if it fixes the shifting.
Note that a previous owner may have tried to solve shifting problems by adjusting the vacuum modulator valve on the transmission, so be patient.
Further, you will need to plug the now opened nipple on the PCV valve. That nipple is usually for other vacuum actuated devices, such as the heat stove. If you have nothing else that requires vacuum, plug it.

5)once the engine is off, I can pull out the pcv and it will rattle, i think that is right?
This is correct.

See if the changes help, and post back.

slickmainer · Post by **slickmainer** » July 20, 2011, 9:02 pm

I have a rebuilt c4 transmission. the PO said it was set up to shift firm and at higher revs.

I'll photo the routing going on. it was all working great till about 2 days ago.

slickmainer · Post by **slickmainer** » July 20, 2011, 9:18 pm

First photo is of the passenger valve cover.

skinny hose (top) goes to some metal tubing then back to a rubber hose and ends up at the back of the vacuum modulator on the end of the c4.

thicker hose (bottom) goes directly to the intake manifold. You can see that at the base of the intake manifold there is another small hose that heads out to the vacuum advance

Second photo is of the vacuum advance line

ezernut9mm · Post by **ezernut9mm** » July 20, 2011, 9:39 pm

see that port coming out of the back of the intake that has the hose going to the pcv valve? that is where the transmission modulator needs to get it's vacuum from.

the pcv valve should be routed to a port in front or rear of the carb spacer so that the pcv vapors are burned along with the air/fuel mixture from the carb.

got a pic of your carb spacer?

be it aluminum or phenolic, it should look something like this.

Alan Mclennan · Post by **Alan Mclennan** » July 20, 2011, 9:45 pm

slickmainer wrote:I know nothing about this so bare with me. this looks like the valve I have

is this a pic of your new PCV valve?, have you cut the end off the small barb?, it looks like it`s capped off!, just asking!. But I agree with Ezer!, the tranny should have it`s own vac supply coming from the carby base!

banjopicker66 · Post by **banjopicker66** » July 20, 2011, 9:51 pm

Ezer corrected me - the PCV vacuum should indeed come out of the base of the carb, usually with a spacer just like he posted.

However, the transmission vacuum should still come from the intake.

And, the vacuum advance should go to a nipple on the carb for modulated vacuum, not directly to the intake.

slickmainer · Post by **slickmainer** » July 20, 2011, 9:51 pm

this is the front of the carb. I assume that is the port you are talking about

slickmainer · Post by **slickmainer** » July 20, 2011, 9:57 pm

@alan- no that is just an image online

@ezer&banjo-
A)intake manifold down the the transmission modulator
B)get new PCV that has only 1 hose and run to front of carb spacer
C)find a way to connect the vacuum advance to a place on the carb?(it looks to be a 2100 2v carb, where would that nipple be)

ezernut9mm · Post by **ezernut9mm** » July 20, 2011, 10:04 pm

gregg, your pcv should go to that port in that last pic you posted. and the trans modulator should go to the port on the back of the manifold where your pcv is at right now in the first pic. then you should be good to go.

you might want to do some checking on the proper hose routing for the vacuum advance as well. that is one of those dual pot advance thingies. it pulled when warm and pushed when cold. i'm not sure if the advance hose goes to the front one or the back one.

banjopicker66 · Post by **banjopicker66** » July 20, 2011, 10:07 pm

Hi again Gregg.
The PCV valve should be drawing vacuum from the spacer just like Ezer said. It looks like it is plugged off, though, can't really tell for sure from here.
That fitting screwed into the back of the intake should be used for power brakes and the transmission, not the PCV valve.
See where the vacuum advance line plugs into the intake fitting? That's where the transmission line should go.

The vacuum advance should draw vacuum from a nipple under the front of the carb, one the same size as the line you are using now - but I don't see one.

banjopicker66 · Post by **banjopicker66** » July 20, 2011, 10:11 pm

Ezer, I think he can leave the second distributor line plugged like it is. If I remember correctly, the one he has plugged retarded the advance under certain conditions. With the rear line plugged like it is, the advance works properly.

ezernut9mm · Post by **ezernut9mm** » July 20, 2011, 10:25 pm

ok banjo. i wasn't sure if you used the front or rear port on the vacuum advance. i know from the factory they used both. one for advance and one for retard until the engine warmed up.

slickmainer · Post by **slickmainer** » July 21, 2011, 9:06 am

banjopicker66 wrote:Hi again Gregg.
The PCV valve should be drawing vacuum from the spacer just like Ezer said. It looks like it is plugged off, though, can't really tell for sure from here.
That fitting screwed into the back of the intake should be used for power brakes and the transmission, not the PCV valve.
See where the vacuum advance line plugs into the intake fitting? That's where the transmission line should go.

The vacuum advance should draw vacuum from a nipple under the front of the carb, one the same size as the line you are using now - but I don't see one.

OK, so the large fitting on the back of the intake is for power brakes (which I dont have), the transmission vacuum should come off the small side port on this fitting where the advance is now. The advance should come off the carb, and the PCV should go to the carb spacer in the front.

I think I got it.

ezernut9mm · Post by **ezernut9mm** » July 21, 2011, 8:33 pm

you do got it. i'll bet it runs lots better when you're done too.

slickmainer · Post by **slickmainer** » July 21, 2011, 9:13 pm

well i moved the vacuum advance line to the side of the carb (under the choke on my 2100 autolite 2v)

I then managed to keep all of the original transmission vacuum line the same but added a reducer connection to a smaller tube in order to fit onto the tiny nipple sticking of side of the larger connector on the back of the intake manifold. The nipple where I used to have the vacuum advance line is really small compared to the size of the vacuum modualor on the C4. i hope that little tube can give the pressure the transmission needs.

I wasn't able to find the right hose and new pcv valve to go on the front of the carb spacer so I had cap off the top nipple of the double pcv valve (old transmission line)and keep the pcv running into the back of the intake till i can find the right hose combo.

All photos i see online of a carb spacer show a smaller thin walled outlet than what is on mine. mine is just a big thick walled hole, so i dont know if the PO stuck something in there to block it off since it wasn't in use or what.

It started and ran and shifted a little better but not 100% what I would expect, and I still got some oil gathering on the outside of the PCV where the plastic meets the metal.

thank you all for your help, at least now I could get it to a shop if needed.

ezernut9mm · Post by **ezernut9mm** » July 21, 2011, 9:59 pm

the aluminum spacers have a thicker port than the phenolic ones do.

351w PCV valve and oil and sound?

351w PCV valve and oil and sound?

Re: 351w PCV valve and oil and sound?

Re: 351w PCV valve and oil and sound?