Ok, clever people. I have a simple one for you. I see many, many pics of engines on this website with lovely chrome air cleaners. I've bought one for my '85 305ci Z28 and it looks great, but it doesn't have a port for the crank case vent tube, like the original one does. How do you guys get round this? If I leave it to vent into the atmosphere, it smells real bad in the cockpit, but I'm told I shouldn't block it up. I can "point" it at the air cleaner, but after a week or so I'm left with a nice black stain on the element. Does the car need, or greatly benefit from this PCV stuff? Bear in mind that I'm from England and we have no emissions laws for a 1985 car.

:hail: to the one who can solve this for me!

Might seem like a dumb question to you guys, but this is "foreign technology" for me!

Si

 

I don't know about on Chevys, but on a VW engine when you change oil filler neck (which is where the "PCV" is on that engine), you install a breather box. It's just a simple little box that the PCV hoses connect to that has a filter inside it. The box itself traps and collects all the oil and still lets it breathe. Maybe that'll help you.

 

Back in the days when gas was quarter and you could
buy Sunoco 260 ...

Oil Breathers consisted of a little can with sort of a sponge/filter
in it. The vapors would escape through the can into the engine
compartment with most of the oil being caught by the sponge.

Look for "oil breathers" or some such in any engine catalogue
often under "dress up items".

 

Either you can use an open breather and deal with the smell of oil in the car, or you can connect it to the bottom of the air cleaner through a tube. Lots of aftermarket companies sell adapters to connect a breather tube to the air cleaner base and the base usually has a round knock-out specifically for that use.
Try Edelbrock or Mr. Gasket at your local speed shop or Summit or Jeg's mail-order.
-Rich-

 

PCV is simply an emissions device to keep the crankcase vapors out of the atmosphere. The simple PCV valve will just suck the vapors back into the engine to be reburnt.

Without the PCV system, the crankcase still needs to vent the excess pressure. A simple pushin breather cap will work. At least that way the engine won't be drawing in oil and water vapor and try to burn it. water doesn't burn too well.

Drag racers don't use PVC at all because of this. Most use an exhaust evac system where the exhaust pulses draw out the crankcase vapors. A newer approach is to use a vaccum or converted smog pump to pull the crankcase down into a vaccum. This can actually increase HP.

For your application you're probably best off just installing a simple breather filter where the PCV is and don't worry about having the engine suck the vapors. If you have too much crankcase pressure you might get a bit of oil slobber around the filter. Excess pressure also causes gaskets to leak.

 

However, if your '85 is a TPI (with MAF) you'll need to close the PCV vent system to make sure the MAF meters all intake air. It sounds by your descrition that you have a carburetor, in which case a breather cap would work adequately.

Ahh, good old Sunoco 260 - gets me right here. The days of 12:1 on the street (none of this camel-urine gasoline we have now), open collectors and cutouts, sucky drum brakes, true Carter ThermoQuads, Isky cams and Offy intakes, Thrush mufflers that would burn out cleanly after two Saturday nights, chicks that couldn't give anything that moldy bread wouldn't cure, chrome reverse wheels and baby moons, and bias ply tires that were measured in hundredths of an inch instead of millimeters. All we get now are faster cars that handle better, get better mileage, and cleaner air. Still, there's something awe-inspiring about 5,000 pounds of '65 Catalina cruising down the road at 125 on skinny tires that just can't be duplicated today.

 

My car is carbureted and has the air cleaner pcv system off of it too. Is the correct spot for the crankcase breather on the driver's side exhaust manifold? Mine just has on open hole, and I am getting a little too much exhaust smell in the car. I also used to have leaky gaskets/main seals that I just replaced. I don't want to have to do this again. Can someone help? For some reason I thought the crankcase breathers were on the valve cover of cars. I am most likely wrong though. Thanks for the help.

 

Well, you went for the chrome air cleaner... why not go for a dress up kit with chrome valve covers? I got a kit like this recently (because my old valve covers were CRAP).. it came with a chrome breather in place of the tube that runs up to the aircleaner. Other side is still a PCV.

 

Well guys, as promised,

:hail: to the lot of you! That has helped no end, thankyou.

Thinking about it now, as the laws are not set up for so much emission gear over here, I think I'd like to remove as much of it as I can. The Cat was the first thing to go! I've also bypassed the charcoal filter. What else can I safely (and tidily) remove? I don't mind if there's a power gain or not, I'd just like to tidy it up in there. Not a lot of people here have the necessary equipment to detect a problem with these complicated (complicated to us foreigners) devices, and replacement emissions gear can get quite expensive here.
It's a 305 carbureted version if that helps.

By the way, now I freely admit I don't know half as much as you guys obviously do, and I know even less than the boffins at the air filter factory, but I've always been led to believe that it's best to get cold air into the mixture rather than hot air. Surely these lovely looking chrome pan filter things draw the hot air rising from the engine? Don't think I'm arguing with the trend, though! Can someone just explain it to me?

Si

 

You are correct. If you are using an Open element air cleaner that sits right atop the carb and engine you are sucking in hot air which hurts performance. You should think of custom making an air box and giving yourself some sort of ram air effect.

 

I'm so glad you said that. It's the only excuse I need! With the LG4 engine, I can't really afford to lose any power. Maybe I'll stick to the original air cleaner assy and polish it up to as-close-to-mirror finish as steel can get. Big bit of hose pointed at the floor (with mesh to keep the stones/birds/small children out). mmm I can see it now...

Does anyone know, if I do all this (and end up keeping the PCV system functioning), what is the best material to soak up the oil and vapours from the vent tube? I tried a sponge but it got soaked in no time at all!

Si

 

Try a charcoal sponge. That's what's in that Charcoal canister after all!