Hidden PCV?

47convert · April 21, 2005, 01:21:45 PM

Does anyone remember the info on installing a pcv valve into the intake? I just got an old Fenton three deuce intake and I'd like to use the oil fill tube as a breather and install a threaded pcv into the back of the intake somehow so I can use period valve covers. I think it was discussed here or it may have been at the HAMB.

SKR8PN · April 21, 2005, 01:40:01 PM

Don't remember the post,but I can tell you how I hid the one on my 360/408 Magnum stroker..........On my MOPAR PERFORMANCE,single plane,MPI intake,I located where I wanted it,(under the throttle body and to the rear a bit),and drilled the appropriate sized hole that the stock PCV grommet would fit. I then made a small aluminum"box" that had vent holes in the sides,stuffed it with aluminum screen,and had a friend weld it to the bottom of the intake,right over the PCV opening.This was to help stop it from pulling oil into the PCV.Then It was a simple matter of running a hose to the base of the new throttle body.

47convert · April 21, 2005, 06:50:06 PM

Good idea with the aluminum shield - hadn't thought of that. I'm sure I saw a PCV that screwd in to a pipe threaded hole.

Dusty · April 21, 2005, 08:36:32 PM

If you are running an electric fuel pump, drill and tap your block off plate on the old fuel pump flange, and install the PCV valve there. You can install a stainless or brass Ell and run a neoprene hose part way up the side of the block, install the valve, and run more hose to the base of the carb...It works for me...

Pope Downunder · April 21, 2005, 10:40:33 PM

Quote from: "47convert"Does anyone remember the info on installing a pcv valve into the intake? I just got an old Fenton three deuce intake and I'd like to use the oil fill tube as a breather and install a threaded pcv into the back of the intake somehow so I can use period valve covers. I think it was discussed here or it may have been at the HAMB.

See this thread.
http://www.roddingroundtable.com/forums/viewtopic.php?t=2332&highlight=pcv

47convert · April 21, 2005, 11:01:12 PM

Neat idea, but I think I'm going to use a mechanical pump. What about this? I have a 3/8" bolt that for some reason has the hex in the middle of the bolt. (threads on both ends) I could chuck it into a lathe, drill through it, install it into the old front mount hole that is usually drilled through into the fuel pump area and run a hose from there into an in line PCV like you suggest. Would it not suck up a lot of oil from the pan without a baffle?

Pope Downunder · April 22, 2005, 08:18:57 AM

Quote from: "47convert"Neat idea, but I think I'm going to use a mechanical pump. What about this? I have a 3/8" bolt that for some reason has the hex in the middle of the bolt. (threads on both ends) I could chuck it into a lathe, drill through it, install it into the old front mount hole that is usually drilled through into the fuel pump area and run a hose from there into an in line PCV like you suggest. Would it not suck up a lot of oil from the pan without a baffle?

Worth a try, not much to risk. I presume you know that bolt hole lines up with the pump push-rod, so make sure it doesn't bind. There must be a reasonable amount of oil splashing about in there, as they can leak quite a bit through that hole if you forget to put a bolt in it.

Whether there is enough vacuum & velocity to draw the oil up is the big question. If it did you could drw the air though a baffled chamber, then up.

47convert · April 22, 2005, 11:15:42 PM

I presume you know that bolt hole lines up with the pump push-rod, so make sure it doesn't bind. [/quote]
Yeh, I was dissapointed to see that hole is not drilled all the way through on this motor. Makes fuel pump installation a little easier. I found a neat Mopar PCV that screws into a 1/8" NPT. I'm going to just drill and tap the back of the intake near the coil bracket and weld a small baffle around it on the inside. Thanx

Skip · April 24, 2005, 12:38:18 AM

The PCV valve regulates the flow of air OUT of the crankcase and into the intake manifold.

Fresh air is supplied to the crankcase by the air intake opening.

In Detroit's V-x engines the valve is in one valve cover and the air intake is in the other. In inline engines, the intake is on one end of the cover and the PCV valve is on the other.

The theory behind the Positive Crankcase Ventilation valve is that it should be mounted as high as possible on the engine and the air inlet should be positioned similarly. This is because the moisture in the engine rises to the highest point when the engine warms up to normal operating temperature. CIRCULATION of the air is the key to a properly functioning PCV system.

If there is a properly functioning PCV system, the moisture-laden air is drawn out of the top of the engine. If there is no PCV system or the system is not operating properly, the moisture in the top of the engine will condense when the engine cools down and sludge will begin to form on the underside of the valve cover(s).

In order for the PCV valve to work there MUST be an orifice somewhere in the crankcase to supply fresh (filtered) air to replenish what the intake manifold has drawn out of the crankcase via the PCV valve. Again, the key is to mount it up high.

On a small block Chev, for instance, air is drawn in through one valve cover, passes down the pushrod holes into the bowels of the engine and back up through the pushrod holes on the opposite side of the engine where it exits through the PCV valve.

The early SBC PCV system drew air into the valve covers and exited through the oil filler tube. This system wasn't all that efficient and was replaced with the current cross-flow type of system.

FWIW, if you simply connect engine manifold vacuum to the grommet where the PCV valve belongs, you'll wind up with a massive vacuum leak. The PCV valve REGULATES the air flow. That's why engines run so crappy when they need a new PCV valve. The PCV valves get sticky and you wind up with a vacuum leak.

47convert · April 24, 2005, 10:46:15 AM

Thanx Skip - I figured on using the oil fill tube as a breather and installing the PCV into the back of the intake - not as high as the valve covers, but still pretty high - I'd hate to drill a hole in these valve covers - what do you thing?

Skip · April 24, 2005, 11:02:27 AM

You will wind up with stagnant, humid air in the valve covers each tome you shut off your engine if you don't force any air circulation through them. That's why pre-PCV engines were always filled with sludge.

av8 · April 24, 2005, 03:10:32 PM

What is the motor -- flathead maybe? If so, what year? They're not all configured alike on this count.

Mike

47convert · April 24, 2005, 03:56:55 PM

Quote from: "av8"What is the motor -- flathead maybe? If so, what year? They're not all configured alike on this count.

Mike

No, I have the same problem with a small block Chevy and a 409. I have really nice valve covers for both and hate like H to cut them up.

HemiDeuce · April 25, 2005, 11:53:23 PM

Hi Skip I know you are a Hemi expert, and was wondering what you think of using a PVC Valve in the valley cover of a 354 Hemi and routing it to the base of the carb and using the stock Oil fill breather as the air inlet for the PVC system, without having a vent in the stock Hemi valve covers.

Skip · April 28, 2005, 10:43:31 PM

Quote from: "HemiDeuce"Hi Skip I know you are a Hemi expert, and was wondering what you think of using a PVC Valve in the valley cover of a 354 Hemi and routing it to the base of the carb and using the stock Oil fill breather as the air inlet for the PVC system, without having a vent in the stock Hemi valve covers.

I ran my hemi like that for just one year and every time I pulled the covers to set the valves, there was a milky brown film on the bottom of them.

I cut my chromed "IMPERIAL" valve covers for Offenhauser breathers (the same as the one on my O'Brien Truckers finned covers).

the breathers are on the front of the covers and I draw the air out through the draft tube opening in the valley cover