Which PCV Valve?

[jhow66]

Now go thru that one more time as I did not get the X=y/Qx+l-3=1

[Orion 762]

X=y/Qx+l-3=1

(this does not look right, unless X = 1.)
???

Bernoulli's Equation Is:

P + (1/2) (rho) V^2 + (rho) g y = Constant

where P = pressure, (rho) is the fluid density, V is the fluid vlocity, g = local gravitation acceleration, and finally "y" is the distance from some elevation reference point.

(I also think Bernoulli was a Communist!!!)

That being said, I think I'll get a new PCV valve with the larger hole (in the bottom) and get the breather intake placed back into the air cleaner (now its simply a breather cap on my valve cover).

I'll also check out GMC Pauls Tech Tips on vacuum gauge tuning at idle (I remember seeing this somewhere else as well).

On a related note, I recall a discussion with my Dad a few years ago on the "pressure from a garden hose with nozzle". He was absolutely convinced that "smaller dia hoses/pipes would give you higher pressure" BECAUSE when you add a nozzle (smaller diameter) to the hose, you get "higher pressure". (He said that you can tell you're getting higher "pressure" because the water shoots out further!!)

I then suggested I'd get a 1/4" dia pipe layed down from the water meter to his house (300 yards away) so that he and Mom could have better "pressure" at his house. Surprisingly he thought this might work!

This goes to show that even reasonably smart folks with otherwise good common sense, can sometimes get things "backwards". This happens in "politics" a lot as well!

Thanks again . . . Orion 762

[bucket]

Does anyone use the hole in the rear of the intake to hook up their pcv? i have a nippled elbow in this location and connect it to either the power brake port at the rear or the 3/8 port at the front of the carb w/ a pcv in between. i think this setup looks cleaner

[texnician01]

what is the part # for that inline PCV valve that you have bucket?

I am using a PCV from a Chrysler. it's got 1/8 in pipe threads on it and it works good but it is just threaded into a hole between the coil and distributor. I also have a breather oil filler tube and sealed Chevrolet script valve covers. I hooked mine up to that Brake booster nipple and it was ok but the velocity is too high and I was pulling too much vaporized oil into the intake. it was puffing white smoke out of the rear pass. cylinder. I disconnected it for the moment cause I had to keep driving but couldn't be burning so much oil either. I will try the nipple on the bottom of the carb and see what that does.

Nathan

[bucket]

i'll check the pn this weekend. as you can see in the pic, that is using the pcv port at the front. when i had it hooked to the brake port, it was a threaded pcv. i will check that pn too.

i had not noticed any problems using the rear port, but it would make sense that it could pull too much vapor through that port.

anyone else have thoughts regarding using the brake port for pcv?

[jhow66]

bucket don't do it!. It will kill the fuel signal for the cylinder nearest the fitting. Hook it up temporary and see what I am saying. Orion 762 clear as a crystal.LOL,LOL,LOL

[bucket]

don't do which........hook up a pcv via the rear of the intake or via the brake booster port?

[jhow66]

Rear of intake.

[jhow66]

just looked at your picture. Do you have a early block? Is it hooked up to the hole in block behind the dist.? If it is do you still have the can under the intake? If not it will pull oil like crazy out of the lifter valley. You cannot run you PCV and brake booster off same line as the booster is a closed system and the PCV an oped one. Your booster would not see a strong enough vac. signal.

[texnician01]

the problem with mine was that I have a newer block with older intake and chevrolet script valve covers. I needed a way to vent the block. We know what the older engines used under the intake cause I have one in the shed but we figured we'd try it just to see what it would do. I'm gonna make a can type device like that and use it . the rear brake port doesnt seem to care if it is capped or has a pcv on it. I don't have a booster and from the pic neither does bucket. hope that helps the explanation.

Nathan

[bucket]

yea.....i have a late 66 327 block. the pcv hose is connected to the opening next to the distributor. weren't these originally used for the road draft breather?

there is a baffle can under the intake that is part of this system. the pcv dosent seem to be getting oil in it.

originally, my engine had a rochester 4G carb on it. i think these were the predecessor to the quadrajet. anyway, when i bought the truck, the pcv was hooked up using this road draft port and a port at the rear of the 4g w/ solid valve covers. pretty sure this was stock, but not sure.

when i switched to the edelbrock i called their tech line and they said i could hook up the pcv via the rear brake port. but as you can see in the pic, i hooked it up using the front port.

[jhow66]

You both are right. sorry I did not notice the manuel brakes. The vac port I was talking about killing the signal was the one on later intakes where it screws into the intake runner. No reason for it not to work the way you have it.

[texnician01]

Yes the pcv hooked up to road draft tube was stock. They offered an adapter to convert it to a pcv if it was originaly a Road draft. the only problem with mine was that I don't have the can under the intake yet. I can't use one like you have cause my block is too new. so I have to manufacture one. but prolly won't happen before I go off to the big sandbox over the pond. Have to wait until I get back.

thanks

Nathan

[jhow66]

Nathan, very best of luck to you and your wife . We all appreciate what you all are doing for us.