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Discussion Starter #1
Im trying to hook up my PCV on my cleveland, and its not being nice to me. When I hook up the pcv valve, it still idles just fine, but any change in acceleration, the car stutters, like a vacuum leak type thing. Do I have to change stuff on the carb at all when I hook up pcv? Heres what I have currently: holley 3310, pcv on valve cover grommet, breather on other valve cover. PCV hose going to large port on the base of the carb. It runs fine without PCV, with pcv idle is good, once you get going its good, but any acceleration it sputters. Do I simply need larger accel pump shot?
 

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OK ... I'll chime in ... Then grab my ankles so you all can kick my A$$


I just eliminated PCV on two vehicles ... One is my 351C 4V ... I simply vented both valve covers to the air cleaner.

I did some major refabrication to the air cleaner assemblies on both cars. I have one (valve cover) vent to aircleaner "inside the air filter" and the other vents to the air cleaner on the "outside the filter". I figure there is a small amount of "Vacuum Assist" expecially to one venting inside the filter.

Both engines run better without the PCV. I see zero ill affects.

It is my opinion (and you noted this in your post as well) that PCV is little more than a controlled "Vacuum Leak" as far as your induction system is concerned.

Rest assured folks will tell you that you are not properly venting your crank case if you eliminate the PCV ... As I see it ... as long as pressure can freely exit the crank case ... you've got it whipped.

Ok Guys ... I'm ready
 

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A properly functioning PCV system will extend engine life 2-3X!!! It does this by "sweeping" blow-by diluents from your oil. You can accomplish similar results with a "road pipe" from a valve cover vent that extends below the engine and has a 45 degree cut facing back. The air flow over the cut creates a partial vacuum and provides the positive venting while under way.

If it is an all out race engine that sees frequent rebuilds and/or frequent oil changes, a PCV system has no significant benefit as long as the crankcase is well vented!!

If it is a street engine that will see years of service, I would definitely keep the PCV system in place!!

My $.02 worth,
Cobrajack
 

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I know, Guys are going to tell you I ran it this way and I ran it that way, but a pvc system should be closed. It is possible that the vacuum pull (or no pull) with that open breather is having an effect on your power valve under acceleration. Just try this. Either close off the hole where your other breather fits in the valve cover, or tape up the little holes in the breather, and see how the car runs then. If it is better, then you need a closed breather, if it isn't..... I'll go back to my garage and just be quiet.

Dan



<font size=-1>[ This Message was edited by: danpmcd on 2/21/02 8:06pm ]</font>
 

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put a filler cap in place of the other breather. when you step on the gas, the pcv port on the carb pulls vacuum on it, and the air goes in the breather you have on it now. In essence you have a vacuum leak. Try it and see if it helps
 

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Discussion Starter #7
Thanks for the advice, I'll try it this weekend and let yah know how it goes.
_________________


<font size=-1>[ This Message was edited by: Brian M on 2/22/02 2:02pm ]</font>
 

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My turn my turn....
Back to basics...
The PCV system is used to reduce emissions. A closed engine system draws air in through (typically) the oil filler cap. An operating engine creates a slight vacuum. The air passes through the motor and is drawn through a the pcv into the motor above the butterfly line.
When the motor idles the pcv is closed while it is most open during acceleration.
If a pcv system is going to be used, the motor must be tuned to take into account the potentially vapour rich mix during acceleration. The source of air must be considered just as any other source of air would be.
Some things to check however are if the oil filler cap/breather has a seal to the rocker cover and the dipstick has a reasonable seal also. A lot of pcv systems actually pipe the air into the air cleaner housing on the engine (not atmosphere) side of the air filter element.
Also is the pcv pickup baffled.
They can pick up oil during max vacuum (acceleration) and therefore be adding oil to the fuel mix, changing the mixture radically.
If you ever want to see how much oil the bastards suck up, plumb in a little glass jar (150ml or so) into the system, and you will find 50ml of oil in there in a matter of days.
I have had to do this as straight propane engines have no "washing effect" on the oil by wet fuel and so raw oil eventually makes its way to the rear two inlet valves and forms stalagtites (the poking up ones).
 

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Discussion Starter #9
Ok so today I was gonna do it, and couldnt find anything to plug the hole. I did however find out why so much oil was leaking, the end seal on the back of my intake had come out, literally slipped out. The 2 bolts on my intake i used were crappy, and didnt get torqued properly, leaving no pressure on that rear seal. Dug around for new bolts, found some good ones put em on, torqued em down. Hopefully that will seal good enough, since I cant afford a new gasket set right now. Tomorrow im gonna run to kragens and find something to plug my breather, and see about the pcv tomorrow.
 

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Hey Brian! all your trying to do here is see if the open breather is the problem. You don't have to spend money to do that. Cut you a piece of cardboard in a circle and duct tape it over the hole and take the car for a drive! Does it run better or not. If it does, buy you a closed breather, if it doesn't, start looking for something else as the problem. Just do it!

Also.......Your intake leak. This is the reason nobody uses those intake end seals anymore. They are more problem than they are worth. When you get ready to put it back together, throw the end seals away and just run a 1/4 inch bead of silicone on both ends of the block let it set up for about a half an hour. Then install the manifold port gaskets and set the manifold down on top of the silicone gently. Once all is in place, install your bolts and snug it down.

Good luck!

Dan
 

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Hmmm ... "No Body" Uses manifold end seals??

I use them ...

Brian ... all you do is use a bead of silicone on the block under the end seal ... install the end seal on the block and let it set up, preferably over night ... Then use a small bead of silicone on the top of the end seal and install the manifold.

The end seal will be secured to the block and will not budge (ever) ... because it was secured prior to the manifold being installed

That end seal has much more structural stability than a bead of silicone (in my opinion)

I know ... lots of people use a simple bead of silicone ... but not me ... the procedure I describe will resolve the issue guaranteed



My two cents
 

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QUOTE
On 2002-02-25 01:09, MonsterMach wrote:
Hmmm ... "No Body" Uses manifold end seals??

I use them ...

Brian ... all you do is use a bead of silicone on the block under the end seal ... install the end seal on the block and let it set up, preferably over night ... Then use a small bead of silicone on the top of the end seal and install the manifold.
---------------------------------------------

Why would you need all that silicone on the top and the bottom of that end seal? Are you afraid it might come out?

MonsterMach.....You are not giving him good advice. I've had those end seals come out but I have never had a manifold leak back there using just silicone. At least on the last 5 manifolds I've put on. Not what my Buddy's done.

I did a little research on this and if you will look at your Edelbrock instructions, if you have any, they recommend using a 1/4 inch bead of silicone and not end seals.

If you wil turn to your Weiand instructions, if you have any, they recommend using a 1/4 inch bead of silicone and not end seals.

If you will look at the 400 HP write up on this website they don't use end seals.

What's this telling you MonsterMach?

Since I've already invested this much time in "Try'n to fix stupid" I' going to continue.

Most of us when we modify are engines, heads will be milled, blocks decked and a whole array of differant part configurations are purchased. Those end seal, while they suck in the first place, are for stock engines and their attaching parts.

The man (Brian) told you he had an end seal hang'n out of his engine, why would you tell him to stick another one in there, when there is a better way.

BRIAN, Don't listen to me or MonsterMach, Just do what FORD MUSCLE, EDELBROCK AND WEIAND recommend, THROW AWAY THE END SEALS.

Nuff said

Dan
 

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Ohhh ... Dan is a little testy


My only response is ... I don't have leaks ... I use the seals as I describe ... and if they were pointless and usless ...

WHY DO YOU SUPPOSE THEY MAKE THEM


Dan ... Don't let youself get to thinking your God ... Buddy


And if you look back through the posts on this forum ... You, my friend ... will see that we usually do not resort to calling each other ... "STUPID"

Your cooperation appretiated ... By All, I'm sure.

_________________

Larry Madsen
Las Vegas Nevada



<font size=-1>[ This Message was edited by: monstermach on 2/26/02 8:32am ]</font>

<font size=-1>[ This Message was edited by: monstermach on 2/26/02 9:22am ]</font>

<font size=-1>[ This Message was edited by: monstermach on 2/26/02 12:15pm ]</font>
 

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Sorry guys ... I can't help myself on this one


Re: "Lobe Seperation" Post

"Mach1Morgan and N20Mike" can have a fair and reasonable knock down drag out over complex engine dynamics ...

And we can't even discuss how to install a damn intake manifold without demeaning folks ... What's wrong with the picture?

Fast2 ... I rest my case ...


_________________

Larry Madsen
Las Vegas Nevada



<font size=-1>[ This Message was edited by: monstermach on 2/26/02 12:05pm ]</font>

<font size=-1>[ This Message was edited by: monstermach on 2/26/02 1:41pm ]</font>

<font size=-1>[ This Message was edited by: monstermach on 2/27/02 1:16am ]</font>
 

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can i call myself stupid? cuz seriously even reading this techboard (while very informative) it makes my knowledge.... well the lack of it... seem very large know what i mean?
 

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I know I will probably catch some flak over this but here goes. Larry, I know that you are a man and that you can handle your own problems, but I think this is kind of in general and in response to the above post.

why would you be stupid? That is why you are here to learn. I really truly think that the real "stupid" ones are those that think that they know it all, and will not admit that they dont. Debate is good, and healthy


I dont think that anyone here needs to call someone else stupid for doing something that is or has been successful for them in the past and or present. If MonsterMach states his opinion, he is entitled to do so. If it has worked for him, then why should he complain? He never said that your idea was wrong, he is just simply stating what he has done and how it has been succesful.
Jeff Given
 
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