PCV adventures with a carb converted engine

Posted by TheAbstracted@reddit | projectcar | View on Reddit | 6 comments

So, a little background: I have a 1988 2.3 Ford Ranger that I've been bringing back to life over the last several years as my first project car. I had a shop rebuild the engine in it fairly recently, but there was some problem with the fuel injection and ECU system that was causing bad misfires that neither I nor the shop could figure out, so I took the nuclear option and carb converted it. Everything has been fairly good, but recently I've noticed a bad oil leak, coating a lot of the suspension and frame under the truck and haven't been able to figure out where it was coming from. There was a little residue on the oil separator where the PCV connects to, so I started doing research into that part. (I've been learning quite a lot about cars in the last few years since I took on this project, but I'm still nowhere near being an expert.) So along the way in that research, I happened to learn a bit more about how the PCV system actually works, and it appears I might have made a major oopsie when I was doing my carburetor conversion - I hooked the PCV valve to a vacuum port on an adapter under the carburetor so it can have full manifold vacuum like it's supposed to (at least as far as I can tell), but I ALSO hooked up the valve cover breather to full manifold vacuum. From what I have gathered, this is, uh, less than ideal, and is likely to be why I have such a large oil leak that I haven't yet been able to find the source of. Hoping I didn't permanently ruin some seals or cause any damage, but that's kind of neither here nor there.

My question is, where should I hook this up to? From what I can tell, normally the valve cover breather would be hooked up to the air intake system before the throttle body, but I obviously no longer have such a setup. Some people have said to hook it up to the air cleaner on top of the carb, but mine does not have such a port and I can't seem to find one for a Motorcraft 2100 that does. I've seen the little filters that you just stick on top of the valve cover breather, but I'm getting quite a lot of conflicting information as to whether these are a good idea or not, with some people saying they just create a huge vacuum leak and others saying it sprays a fine mist of oil all over the engine bay. So what are my options here? Thanks for your time.

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igobyraymond@reddit

The valve cover port just needs fresh, filtered air. The small filter that fits directly on the valve cover is easiest. If you have a decent size breather on the carb, you could drill a hole and epoxy a nipple on to it.

As far as the leak goes, there should be clues. Where's the puddle at? Check at the back of the engine where the transmission attaches. A rear main seal will leak into the transmission bell housing and eventually leak out of the bottom of the housing. This can be mistaken for a leaking transmission.

Another common leak on early rangers is the oil pressure sender. It's a bell shaped metal object that will be located on the intake side of the motor, all the way to the back and near the top. Should have a single wire going to it.

The 2.3L is a great little motor, if not the most powerful thing. Good luck!

TheAbstracted@reddit (OP)

Yeah, I'm gonna have to get some degreaser and go to town underneath there, the oil is absolutely everywhere underneath. Looks like it has made its way back to several components on the underside because of the wind while driving. Front side of the engine is clean, but nothing else from the rear of it to the back of the transmission is. I know the sensor you're talking about, the wires on mine have been cut since I got the thing. My best guess is either oil pan gasket or rear main, but once I get it all cleaned up we'll see. Never done either one of those before, so like everything I do on this truck it will be a learning experience!

MetaphysicalEngineer@reddit

There's a chance the excess crankcase vacuum damaged seal(s) which are now leaking. Clean and degrease the hell out of the engine then run it a bit so you can find where the leak is coming from.

The separate filter breather and PCV valve create a small controlled vacuum leak that you adjust for when turning the carb. You may get some oil mist under WOT conditions, but in most cases the flow will be inwards through the filter.

FloridaMan_Inc@reddit

I did a carb conversion on my Honda and ran the ran both the lines into a catch can.

legionofdoom4@reddit

Did you do a separate can for pcv and ccv lines? When I tried to do this on my saturn I got a nasty vacuum leak from teeing in the ccv line into the pcv and connecting to manifold vacuum. Fixed it by routing the ccv back to its factory spot in front of the TB. Did I miss something that'll let me tee in the CCV to my can?

Single can (dual inlet) for both. No tees. No connecting back to the manifold at all. You shouldn't be connecting anything with positive pressure (like vent lines) into anything vacuum related at all.