PVC valve needed?

[dhamilton62]

The previous owner on the 62 c10 put a 350 sbc in it. The valve covers are edelbrock but don't have the ports for a PVC valve or breather and the PVC valve on the carb is plugged up. Is there another way these motor breather or would that by a big reason for why my oil filler cap is puking oil all the time? Thanks!

[chevy_mike]

Yes it would be. You should at least replace your oil cap with a breather style. Not ideal but it will allow the engine to vent.

Do both of your valve covers have oil cap ports? If so, you can get a PCV style for one and a breather for the other. Then hook the PCV to your carb and you'll be good.

[Jimal]

Originally Posted by chevy_mike

Yes it would be. You should at least replace your oil cap with a breather style. Not ideal but it will allow the engine to vent.

Do both of your valve covers have oil cap ports? If so, you can get a PCV style for one and a breather for the other. Then hook the PCV to your carb and you'll be good.

To add to this, if both valve covers have oil cap ports, you'll need some sort of baffle wherever you stick the PCV. Otherwise it'll just be sucking oil out of the valvecover and your truck will smoke. Moroso makes a PCV/breather grommet that works as a baffle.

[dhamilton62]

Thanks so much for the help. My valve cover are solid and don't have ports at all. I'm guessing I'll need to get some new covers and sell these. What's the reason for covers without ports? Thanks again everyone.

[chevy_mike]

Originally Posted by dhamilton62

Thanks so much for the help. My valve cover are solid and don't have ports at all. I'm guessing I'll need to get some new covers and sell these. What's the reason for covers without ports? Thanks again everyone.

Early SBC (up to mid '60's) had a road draft tube at the back of the engine and had the oil filler/breather tube coming up from the front of the intake manifold. With this system, no holes in the valve cover were needed.

When GM went to the PCV system, valve covers started to get holes in them and gone was the draft/fill tubes.

[Captainfab]

I just wanted to add that the PCV should be on the opposite side of the engine from the breather.

[PGSigns]

If you pull the covers you may find the place for the port is cast on the inside. They do this to allow the owner to pick where the ports need to go.
Jimmy

[garmar]

Not allowing your engine to breathe can cause oil leaks too. This is why a leaky oil pan or valve cover gasket is a sure symptom of a clogged PVC valve.

[Todd W. White]

My engine originally had a draft tube. I replaced it with a valve cover set up that allows a breather cap on one side, & a PCV valve on the other. Because it is virtually impossible to find the correct PCV valve for an engine that has been modified, or even rebuilt, I have found that the best choice is to get a field adjustable PCV valve from these people:

http://mewagner.com/

The Nova guys have found these, and love them. I have one on my 65, and it made all the difference in the world.

[Todd W. White]

My 283 originally had a draft tube. I replaced it with valve covers that allow a breather cap on one side, and a PCV valve on the other. I have a terrible time trying to find the right PCV valve for it. I tried everything from the ones originally specified all the way to ones that we just guess that. Nothing worked properly.

Finally, I found a company that makes a field adjustable PCV valve. It is possible with this unit to custom tune the PCV valve to your particular engine precisely. It made a tremendous difference in my engine performance.

Here is the link to the people who make it:

http://mewagner.com/

[Captainfab]

Thanks for that link. It is pricey but it might just be worth it. The PCV is something I have often wondered about which one to use, but I have never been able to find anyone that can tell me how to choose the correct one. I typically use one for a factory high performance application, but I don't know if it is really functioning correctly.

Originally Posted by Todd W. White

My 283 originally had a draft tube. I replaced it with valve covers that allow a breather cap on one side, and a PCV valve on the other. I have a terrible time trying to find the right PCV valve for it. I tried everything from the ones originally specified all the way to ones that we just guess that. Nothing worked properly.

Finally, I found a company that makes a field adjustable PCV valve. It is possible with this unit to custom tune the PCV valve to your particular engine precisely. It made a tremendous difference in my engine performance.

Here is the link to the people who make it:

http://mewagner.com/

[Todd W. White]

You're welcome!

It's not really that pricey, when you consider the cost of wearing your engine internally unnecessarily. It also has improved my gas mileage, believe it or not, quite a bit. I currently get at least 16 mpg in town, and 18 to 20 mpg on the highway. I didn't get that before. I'm running a 283 engine with an SM 420 transmission, 308 rear end, and 30 inch radial tires. My carburetor is a Holley 4360.

[old cool]

If a pcv rattles and looks newer, can it be bad? I have pinched the pcv hose between pcv and intake and got significant suction - like pinching a vacuum cleaner hose. Do these to variables sound like the pcv is working well? I don't like throwing $5 around but I have oil leaks now from pan. If there's undue pressure, and a new pcv would help, that would be great.
FYI, since vacuum leaks cause engine idle and acceleration probs, I looked closely at the grommet going into valve cover (250 6 cyl), it needed changing. It was obvious as pcv was tilted; no longer the case. I also found that the grommet going into power booster was cracked. Could be mind over matter (maybe a new batch of gas - lol) but it seems to have helped steady engine some.

[Snailed]

That M/E Wagner PCV looks like it would really do the trick on modified engines. I'll have to give it a try next time I'm setting up an engine. I have tried all kinds of PCV setups with and without valves but it always seems like stock setups on stock engines just work better.

[markeb01]

Yes thank you for the link. That looks like a dandy device. Consider that a PCV valve only does two things - at idle, it creates a small vacuum leak. At open throttle, it creates a big vacuum leak, all necessary to evacuate the crankcase fumes. But I remember when PCV systems first came out back in the 60's and they were generally hated because before they came along engines could be idle tuned so smooth they couldn't be heard running. The leak caused by the PCV brought all that to an end.

The trade off didn't get recognized until years later, and that was a sludge free engine that looked like new internally. That's when I became a convert and installed PCV systems and eliminated road draft systems on everything I built.

What a brilliant idea to create a PCV valve that can be adjusted like a carburetor. I can see how swapping to this new valve could require adjustments to the carb itself. Thanks again for sharing, this is an incredible piece of technology.