PVC question

[Irishman999]

My 85 ran like **** for 2 years, I replaced everything from the heads up trying to figure it out. My dad plugged in a pcv valve and it ran absolutely perfect....

 

[r.booser]

My 85 ran like **** for 2 years, I replaced everything from the heads up trying to figure it out. My dad plugged in a pcv valve and it ran absolutely perfect....

What did you have before you changed it? Just a breather?

 

[roving4s]

I think it's a myth, I've read and seen. That you don't have to run it back in the carb. Breathers or catch cans worked just fine. Then there's people who say if you don't it will run like ****.

Why didn't older vehicles have a pcv ?

 

[Irishman999]

What did you have before you changed it? Just a breather?

I might have just had a plug in the valve cover, I cant even remember. For all I know it was an open hole, I really did not care about that engine too much.

The carb needs a pcv valve to run right, its also one of the oldest most important emission control on an engine. If you dont run a pcv valve acidic gas forms in the crank case and it eventually eats your aluminum bearings.

As far as the port, you might break it if you try bending it back. Its worth a shot, if you break it off in the carb you can always drill the hole out and try to tap some threads so you can just screw in a barb fitting.

If you want to do a proper repair just pull the carb off, heat the area around the fitting a little bit with a small propane torch and pull it out with vice grips. Not sure exactly where you find the new ones but I am sure you can find them somewhere.

 

[r.booser]

I have had about a 50/50 on people saying there is no need and a breather is fine and others say it must be hooked up. Since it is an easy fix I will but that is a good debate.

 

[Irishman999]

I have had about a 50/50 on people saying there is no need and a breather is fine and others say it must be hooked up. Since it is an easy fix I will but that is a good debate.

I dont know how your truck is running but mine had these problems:

Idle would be okay while the engine was warming up, after driving the idle would be all over the place and rough. After a little bit of driving it would stumble from a stop and hesitate to take off. Driving on the highway was affected too very little power until I would let off the throttle and the power would come back. If you held it to the floor it would just bog and slow down.

I rebuilt the quadrajet twice, converted to a Carter AFB (same as 1406 eddy) and then rebuilt that. I changed fuel pumps twice, replaced the intake with a brand new edelbrock performer 2 and ran a phenolic carb spacer because I thought it was vapor lock. At one point I even got it a brand new distributor, several sets of plug wires, new plugs.... I changed just about everything with no change in results.

My Dad seriously grabbed a pcv valve and some hose of his bench, plugged it in and it ran like it was fuel injected. We re adjusted the timing, changed the idle speed back where it should be and the thing ran a like it was brand new.

Absolutely no doubt in my mind the pcv missing caused all that!

 

[r.booser]

damn that is crazy. I haven't ran it but around the block a few times. When I got the truck (had it a week) it had a bad dizzy and needed the carb adjusted bad. Just got all that finished and now I have to replace a few houses since they are just old. Tonight I'll take it for a drive and test it out. The PVC isn't hooked up now so if it does what you say then looks like I know exactly what is wrong. Thanks.

 

[Swims350]

lol forgot to mention it's actually pcv, not pvc that's plastic LOL.

 

[r.booser]

haha hey we are in the judge free zone here.

 

[skysurfer]

Why didn't older vehicles have a pcv?

They had road draft tubes, basically a 1" diameter metal tube coming off the engine and hanging down into the air stream below the vehicle. At speed, the vapors would be pulled out of the tube in much the same way cigarette smoke does near a slightly open window. They were outlawed for production cars in the early 60's, my '59 MGA still has one since it's oem and doesn't need to be modified.

 

[GTME94]

Some of the heavy duty diesels still had road draft tubes until about 5 to 8 years ago.

 

[roving4s]

See previous life was just fine, before the epa bs. I knew older vehicles had draft tubes, I was just stating why pcv. Is either yes or no I still think it's a epa thing.

Besides with all the epa and gov restrictions etc. That's one of the reasons we don't get alot of other vehicles in the country.

 

[GTME94]

Well PCV is actually good for your engine. The old road Draft tube required your car to be moving for it to work. The PCV uses engine vacuum so it always works except for a few instances of low to no vacuum. It is good to get the water vapor and extra combustion gases out of your crankcase.

As for the import of other vehicles, crash requirements are as much a reason for not importing cars as emissions. And emissions regs are getting closer globally all the time. Even China is requiring Euro emissions standards on new cars now. And it goes both ways, those other countries can't get some of our cool cars either.

 

[roving4s]

I still can't see why, you'd wanna burn contaminated fuel fumes. I'd rather vac them out of the engine not back into it.

 

[bobkyle2]

In our race engines this year, we are running tubes from the valve covers down to a the collectors on the headers.