Here's another PCV Valve and System thread for discussion. Sorry if this is ploughed ground...

I got the 240 running much better today by disconnecting the PCV valve. You all were saying "Its a vacuum leak!" The PCV valve apparently is a MAJOR vacuum leak I hadn't considered. So I pulled the valve from the rocker cover and capped it off and the idle is great. The questions I have now are specific to the PCV system and I didn't want to go off topic on the EFI Manifolds thread.

I plumbed the PCV system into the intake manifold. Maybe I have the wrong PCV valve. What are others with similar vintage 240 using for a PCV valve? Isn't this how it's supposed to be plumbed in (R/C to intake manifold)? Do I have it going into the wrong location? The pipe/hose diameter are 1/2". Too large pipe/hose?




PCV Hose routing to Intake Manifold


PCV Hose to Intake Manifold

 

This is what I posted on the EFI post:
'Well at least you found where, and vacuum leak is but if you have a PCV installed (right way?) it should not have a vacuum leak
That is a valve and not just a nipple to get the hose into the cover is it?
I think the motor is too new to have a road draft tube right? So why is the PCV causing a vacuum leak?
Dose the valve rattle if you shake it and it looks new."

The hose / pipe size should not make a different or where you have it but for S&G move it up to the nipple closer to the carb in the picture and see what happens.
I am guessing the same "vacuum leak".
Do what I above with the rattle.
What is the valve to, year & motor size?
If you put it back in the cover and it shows a leak pull the oil fill cap / breather, and put your hand over the opening to seal it do you still have the leak?
I guess it could be a bad valve I just never had one go bad before.
Let's see what others have to say.

BTW on my 81 the PCV has 2 nipples, 1 for the supply to the manifold and the other is for the fuel vapor canisters to pull the fumes into the carb to burn them when the valve opens to do so.
Well, I don't have a valve but figured I could just hook it to the canisters. Like you I could not get the idle to come down where I wanted it. After checking all over I found the vacuum hose to the canisters was the vacuum leak.
It was pulling too much vacuum; my fix was to take the smallest Holley carb jet I had the stick it in the hose to restrict vacuum. It worked but it still pulls a little more than I like but being lazy it has been that way for years but the idle is where I want it so that's a win for me

Good luck on the drive.
Dave ----

 

Dave et all;
The engine, when I torn it down many many moons ago, used a PCV valve an no road draft tube. I was considering a draft tube as a bailout option but I'm not there yet. That engine had so much blow-by it was difficult to keep the side cover and valve cover from leaking. She was a smoker for sure. The original owner (a little old lady from Sun City AZ) drove it to church, the grocery store, doctor and pharmacy. Short trips every time.

The existing PCV valve is spec'd as for a 300 (according to the catalog listing from NPD). I bought it as it was the best fit for the grommet I found that fit the valve cover I'm using. The PCV valve rattles when I shake it. The upper or higher fitting that is part of the carb base and not the spacer plate, is in line with the throttle and kickdown linkage and the routing to the upper nipple looked problematic without more bends and formed hoses. I had to fashion some kind of bracket to keep the PCV hose from drooping and resting on the intake manifold.

I inserted a piece of hose inside the 1/2" ID hose I'm using for the PCV system to act as a restriction in the PCV hose. I reinstalled the PCV valve and the idle is back in the normal range. I've been able to drive the car to the gas station and today it went to the exhaust shop for a new stainless exhaust system. Once its quieted down a bit, I'll be doing some engine break-in drives. I've also learned that the distributor I'm using (the OE Loadomatic) doesn't like to play well with the aftermarket carb, but it will do for now.

Nice work around for your leaking cannister hose. Ya gotta be creative sometimes.

 

When you get the car back I would like to know when the vacuum is at idle.
I also would look at getting a PCV for a 240 of your year and change the rubber grommet to fit. You should be able to find one at the parts store.
Is the valve cover from the 240 or something else? Valves are made for the motor and vacuum it should have.
Dave -----

 

I'll recheck the timing and idle speed when I get the car back from the exhaust shop and reconnect the vacuum gage.

The valve cover is off a later models (unknown year) 300 I got at the U-Pull-It 10 years ago or so.

 

My gut tells me it is the valve as I cant see it being anything else.
I do know they are make to fit certain motors and not be swapped between motor sizes / years.
Could it be either bad or wrong for that motor?
Dave ----

 

expolice: Do you have pics of how you installed the throttle cable on the Holley 4160C with the Offenhauser 6019-DP? I looks like everything must be reversed but I cant tell from the pice how you made the 180 degree turn back towards the captain-side firewall.

 

It would also be nice to know if he got it fixed but it has been over a year now
Dave ----