Oil Catch for PCV system

Status
Not open for further replies.
My son's 88 Cutlass 2.3 Quad 4 has a crankcase vent oil/air seperator from the factory. It drains out the bottom back into the engine.

I'm fixing to donate it to which ever non profit foundation will drive it away. The oil/air seperator is made of plastic and sealed but now y'all done got me curious - might have to cut it open for a peek.
 
quote:
Originally posted by carrera79:
Would there be any reasoning behind thinking that expelling the gasses into the air would somehow mess with the computer's ability to efficiently manage the vehicle? I'm going to take a look at doing something with an aluminum pipe along the lines of the PCV thing, only with the inlet and the outlet on the top (i'll run an internal tube to the bottom for the inlet)
Click to expand...
Only if you do not block off the intake tract and create a huge vacuum leak. It's still better to get a profesionally made catch can and hook it back into the intake vacuum, so the metered amount of air is till gointo into the engine.
 
I have been reading this topic and still don't understand if the PCV system and engine blow-by are normal and functioning why you would need an oil catch? I can see moisture catch on cold start-up. I have never had a problem with oil in PCV system.
Anyway in regards to Gary's post on the exhaust setup there is another system out there called "Krank Vent" that is supposed to replace the standard pcv valve and provide a slight negative pressure to crankcase. Similar benifits stated as with the exhause type. Only problem I could see with exhaust type is it will suck when you let off gas and blow when on accel. Looks like the check valves are there to cover that but the welding would be a trick. This Krank Vent is apparently used on racers but I've never spoken to anybody who has one. Here's the web site. Any comments?
http://www.et-performance.com/krank_vents.html

[ April 24, 2004, 07:24 AM: Message edited by: needtoknow ]
 
quote:
Only problem I could see with exhaust type is it will suck when you let off gas and blow when on accel. Looks like the check valves are there to cover that but the welding would be a trick.
Click to expand...
Those extractors are check valves...but they are there only for backfire protection. The exhaust flow will naturally "induce" a vacuum on the crankcase. This is used for fishtank aeration and "weed and feed" syphon tubes for your lawn.

Welding is a simple matter for any qualified exhaust shop. The great part about it is that you never have to fool with it again ..probably for the life of your car.

I'm unsure why it was abandoned by GM and others. Pehaps they determined that the blowby vapor, because of other technical advancements, was better going through the entire combustion process before being expelled instead of just being exposed to the "after burn" that would occur with the added air. That is, the "before and after" O2 sensors may be fooled.

I would think that this could be remedied by installing it behind the cat.
 
I went to pep boys to try out thump186's post. I really liked that setup. They ordered the parts for me and I'm waiting for arrival. I have had some oil in the PCV system in every car that I've owned. I'm not talking about some great amount, but now I'm dealing with an turbocharged and intercooled vehicle and any small amounts of crap in from the pcv build up in the intercooler. I just washed the thing and it was pretty filthy after 120k mi. BTW-I also did the fuel filter, it looked original. I don't think anyone in the real world (not bitog people) change the things.
 
quote:
Originally posted by Gary Allan:
Why not use the exhaust draft to pull the blow by gasses into the exhaust stream? This works well. I'm uncertain of the long term effects on some of the newer cats or multiple O2 sensor arrays. This was OEM on many GM's of the late 70s and at least some of the 80s.

I always liked the "no maintenance" feature of this type of installation
Click to expand...
is it me or i dont know how that works period??! i know a can is used to catch the heavey oil in a pcv line, but that one just makes my mind boggle.
 
quote:
is it me or i dont know how that works period??! i know a can is used to catch the heavey oil in a pcv line, but that one just makes my mind boggle.
Click to expand...
The pipe pointed downstream into the exhaust flow creates a "void" in its "shadow" ..this creates a vacuum or pressure differential in that void. It "induces" a draft. The velocity of the exhaust flow won't let it change direction ...so it pulls anything in the void (or any vapor piped to it) along with it. The exiting exhaust gas is compelled to fill the void ..but because of its velocity ..can't do it immediately. The void doesn't care what fills it ..it's a relative vacuum ..it's open to all comers ...even whatever you have vented to that pipe ..be it open air ..or heavily saturated oil vapor.

Ever critically look at how a sand blaster works ..a propane torch ...a dynamic drain cock on a small sail boat? Same thing.

These were developed by Grumpy Jenkins for racing. GM adopted them for OEM installations (2.8 Citations for one).

Anyone else got a more articulate description of what I'm trying to say? That is, without a five paragraph expanation?
 
Good idea Gary - though the emissions testing may become a problem. Also you could cover your catalatic converter with the oil.

Its called a venturi. Some very effective vacuum pumps are of this type. They have a high pressure-high velocity stream of air pass by a small orfice. At the orfice a vacuum is created.

Carbs use the same principle.
 
I have this same problem on my Maxima. Opened the intake manifold at 30k and found pooled oil in the intake.

Went to Home Depot and picked up a water/oil separator and some hose. Have only put 60 miles on it, but I have almost a teaspoon of oil in the separator. Something about the Nissan 3.5L really pulls oil through. Never had any oil loss though.
 
Old (OM616 and 617) MB diesels have a cyclonic oil separator system to get the liquid oil out and burn the crankcase blowby. Works well.

Find one of these (you can actually find the MB part number on the net, Im sure, try www.mercedesshop.com), and then plumb it into your PCV system.

JMH
 
Most of these solutions, with the exception of a crankcase evacuation system, are basically shop vacs. You have to give the oil vapor a big (relatively) chamber to lose all of its velocity. No velocity ..no heavy, oil laden, vapor to the engine. If you can incorporate a drain return to the valve cover ..so much the better.

This is how shop vac, spray driers, and lots of other "stuff" manages flow without particle or vapor entrainment. You just rob it of what keeps it in suspension.
 
Gary, taking your point a step further: could a decent trap be made from a inline fuel filter housing (thereby obtaining the required hose end fittings) and stuffing it with cotton or a foam breather element?

This is exactly how my moisture trap works on my airbrush. Oil -vs- water vapor may be a bit different, as well as the flow rates, but what do you think?

ideas?
 
-


Thats exactly what i want on my 98 infiniti I30 (same as maxima) anyone wanna do a write up of what to buy and how to install this?
thanks
 
I run two of these - one for each bank on my V8 - and they seem to be working as well as any other solution. which is to say, a slight improvement but not a cure

http://www.f150online.com/galleries/pictureview.cfm?pnum=110810&anum=7528.

But my truck is, admittedly, a bit unconventional. Boosted modular Ford motors have a really bad blow-by problem, stock Lightnings and aftermarket blowers alike.

At least as far as the modular Ford motors go, no one has come up with a great solution yet. The pricey catch-cans work no better than this budget setup.
 
Thats what I have. All you need is an oil/water separator, some plastic 1/4 to 3/8 connectors and 3/8 inch hose.
 
Anything that allows it to lose its velocity will usually work. I've used larger oil/moisture separators in the past. I imagine if you could find a remote mount for a spin-on fuel filter (like a light duty diesel sized)..one that has a water drain on it, that that would be a pretty good setup. Everything should just sit in the bottom and you can just open the tap from time to time to drain out what it collects.

If not for the sophistication of the electronics, I often toyed with the idea of using full manifold vacuum on the crancase, like my old BMW did. You would have to provide some kind of backfire prevention, but the true blow by emissions should just be dissapated very soon after entry into the crankcase. There wouldn't be much velocity to the flow (high suction .low flow- just like holding your hand over a vacuum cleaner hose) ..so I would think that it would keep things nice and tidy ..except in exteme circumstances.
 
Status
Not open for further replies.

Similar threads

TiGeo
Rigged up a catch can
Replies
14
Views
679
TiGeo
J
PCV systems and catch cans with different engines
Replies
1
Views
589
SHOZ
JHZR2
Would you retrofit this PCV seal?
Replies
5
Views
291
JHZR2
0
Long Term Fuel Trim at 20% 04 Mazda 3 2.3L
2
Replies
27
Views
769
00scrub
wwillson
Crank Case Ventilation (CCV) the source of oil consumption in the GM 3.0L Duramax?
2
Replies
21
Views
1K
wwillson
Back
Top Bottom