Is it safe to install an oil catch can?

[kilou]

Quote:

---

I am in Norther Ontario Canada and I had no freezing whatsoever. There is enough fuel and other components to keep it liquid at even -40f. It got thick, but never solid.

________ at -40f, the oil was thicker than what was in the catchcan.

---

Are you able to drain the goo through the drain nipple at the bottom of the filter? Mine cannot even drain engine oil at room temperature...

I checked the filter in my fridge, the water is all ice now....and no sign of crack in the bowl

You're in Northern Ontario! Close to Sudbury/North Bay??? I was there last May! Very nice place! I love Canada

 

[BlazerLT]

Quote:

---

Quote:

---

I am in Norther Ontario Canada and I had no freezing whatsoever. There is enough fuel and other components to keep it liquid at even -40f. It got thick, but never solid.

________ at -40f, the oil was thicker than what was in the catchcan.

---

Are you able to drain the goo through the drain nipple at the bottom of the filter? Mine cannot even drain engine oil at room temperature...

I checked the filter in my fridge, the water is all ice now....and no sign of crack in the bowl

You're in Northern Ontario! Close to Sudbury/North Bay??? I was there last May! Very nice place! I love Canada

---

Sudbury!

You don't drain through the nipple thing seeing this filter was supposed to be used with a pressurized system. Seeing when pressurized it will push the stuff out the bottom. With a vacuum system this won't happen properly.

I just unsrew it, dump it, and rescrew it on.

Works mint!

 

[yugrus]

I drain through nipple every other day without problem. The goo is not as thick as oil, and it drains nicely.

 

[Drew99GT]

Every other day? You're gonna wear out the hinges on your hood!

I'm afraid I will to on my car since I have to top off about once a week. Well, it needs about half a quart by then but I like keeping it at full.

 

[yugrus]

I check under the hood every day anyway. You know... Some people admire fine paintings; I like to see that my oil level stays the same from last night

Anyway, I tried to improve the catch can performance by adding a bit more surface for the vapors to collect on. I took a nut and threaded a bunch of stainless steel ribbons through it, so they formed curly circles. I used a stainless sponge for that. The goal was to prevent any debris from sucking into the engine.
The results were opposite of my expectations. The catch can collected much less goo during two days I was running with this set-up. Last night I removed this porcupine from the can, and it collected the usual amount of oil.
Interesting.

 

[crw]

Interesting... I wonder if you will catch more or less oil in any particular engine based on the weight you are running?

 

[BlazerLT]

Not really, it is directly related to the amount of blowby from worn rings.

 

[mechtech2]

There can be problems in the cold with a catch can. If vapors congeal or freeze, air/gas flow can be curtailed until it warms up.
It is very hard to drain in cold weather, at a minimum.
I use a catch can, and will reroute it closer to the head for winter operation, as the extra heat will help.

 

[wiswind]

I installed a greddy catch can on my '96 3.8L windstar.
Has been on for a good 6 months now.
It is toward the end of my pictures at
http://community.webshots.com/album/201931518cScpNK

I bought extra hose, in addition to the hose that came with the can.
Installation was super easy.
I have not had to empty it yet, but cool weather has just gotten here.

Oil consumption is not an issue.
I installed it to keep the intake clean.

 

[kilou]

After MANY trials on how to route the rubber hoses, I finally installed my oil catch can (Husky filter). I made less than 20km.....and removed it immediately! I checked the crankcase vacuum by plugging a home-made gauge on the dipstick hole. This measure the vacuum directly in the crankcase and is a reliable measure of the vacuum available to pull out blowby gasses. With my install I had almost no vacuum in the crankcase (less than 0.2cm of water). I then removed the oil catch can........and immediately had a crankcase vacuum of about 1.2cm of water!!!!!!!!!

Of course my install is not the best one since the fittings make several turns and thus reduce the suction force. Unfortunately I don't have many ways to route the hose and after many many trials this was the best I could achieve.

So at least for now I won't use the oil catch can and I have reverted to the stock setup. Flow restriction was a real concern for me and unfortunately my setup did significantly alter the efficiency of the PCV. I prefer having to clean the intake.....than blowing an RMS!

I would strongly advise those who have installed an oil catch can to check their crankcase vacuum. I must agree that my design is particulary restrictive (too much bends) but this is all I could do. I completely removed the filter inside the plastic bowl so this was not the origin of the flow restriction......and the pipes diameter is the same as the stock hoses too.

Too bad, the oil catch can looked so great in the engine bay....

 

[SHOZ]

Here is a pic of my self draining one from a couple winters ago. This is with temps in the 20Fs.

 

[Dave H]

I had posted previously that I didn't see any difference with my catch can's collection of goo while using the little white "stone" filter and without using it. With or without that filter, it collected the same amount. I recently modified it by cutting the white "stone" filter off of the threaded portion, then threadeing the assembly back in. The "assembly is the black "gear" looking piece at the top that is held in by the threaded portion of the white filter stone. After doing this, I can easily say that the amount of gunk caught by my catch can has easily doubled. It seems this "gear" directs the air going through the catch can somehow, allowing more gunk to condense in it. I guess without the gear piece, the air flows almost straight through the catch can from one hole to the other. To put the gear back in, you have to use the threaded portion of the white filter. And the white filter has to be cut off of its threaded portion. It's made of some kind of plastic type material, so even a steak knife will go right through it.

Anyways, just an interesting observation I've made.

Dave

 

[Drew99GT]

Quote:

---

Regarding the stone, you can simply unscrew it but that leaves a direct path from inlet to outlet so I broke the stone off of it's little plastic mounting thing and screwed that little piece back on because it holds like a baffle type thingy at the top which diverts the flow right against the plastic container to condense moisture.

---

(my previous post in this thread)

That's exactly what I did Dave. Mine cathes a TON.

 

[yugrus]

I have the same set-up with the foam filter cut off. Every day (100km of mixed driving) the can catches just enough goo to cover the drain hole. I drain every night.
I wouldn't say that my set-up catches a ton, but I bet it helps.
I'd like to get a kind of a "dry" vacuum gauge to replicate Kilou's test. I'm not going to make my own water gauge, I'm sure with my luck I'll get half of the water right into my sump...
Any ideas?

 

[kilou]

Quote:

---

I'd like to get a kind of a "dry" vacuum gauge to replicate Kilou's test. I'm not going to make my own water gauge, I'm sure with my luck I'll get half of the water right into my sump...
Any ideas?

---

There is no problem with a home-made "water" gauge to check the crankcase vacuum. Just take enough hose and move the end slowly towards the dipstick hole so that the water will gradually move up. If it moves too much you simply remove it from the hole. Easy, safe, quick and probably more than enough for the accuracy we require!

My last design was really bad and the vacuum couldn't reach the crankcase so the blowby gasses were not sucked up anymore. I'm thinking of a new design that would save 3 turns....but requires a bit more job.

Anyway if you do vacuum tests you should check the crankcase vacuum both at idle AND under load (like at 2000rpm and 4000rpm...or more if you like). This will accurately show if the vacuum is enough under all circumstances. On my car the gases are sucked after the throttle body at idle while they enter the intake before the throttle body under load. So we need to check both conditions to make sure we'll not blow a seal with our installs....

 

[kilou]

Just wanted to add that my crankcase vacuum moved the water by less than 1.5 cm without the catch can so you will be more than safe with a small length of plastic hose to connect to your dipstick hole. We are measuring crankcase vacuum, not direct manifold vacuum!

Warm the car first!

 

[yugrus]

Quote:

---

On my car the gases are sucked after the throttle body at idle while they enter the intake before the throttle body under load.

---

Let me respectfully disagree with that. My understanding is that your throttle creates vacuum inside the throttle body (after the butterfly valve) regardless of the mode. The pipe before the butterfly is the fresh air intake for PCV system. If your engine is tight and does not have a lot of blow-by or fumes, etc. in the crank case, this fresh air intake prevents from the high vacuum build-up that might implode engine's gaskets.
Anyway, the dirty gases from the crankcase are always sucked through PCV valve into the throttle body, after the butterfly. The PCV valve reduces the flow at low RPM and maintains or increases the flow at high RPM. At high RPM the TB vacuum is lower then at idle, so PCV valve opens up to compensate for that.
There's the only case when gases can flow through the fresh PCV air intake tube- when the blow-by is high and PCV valve is clogged, but I'm sure that's not your case.

 

[kilou]

Yugru, your description sounds right for most cars but I'm not sure it's also valid for mine. Let me explain why:

My car (Volvo S4o non turbo, engine not available in USA/Canada) doesn't appear to have any PCV valve. No sign of such valve on Volvo part diagrams and when I renewed the whole PCV tubing and oil trap a few weeks ago there was no valve. Originally the car was fitted with a flame trap (not requested anymore by Volvo now) that was mounted on the PCV line that goes into the intake duct BEFORE the throttle body. According to your description this should be the fresh air tube but as a flame trap is designed to prevent ignition of blowby gases past it I guess there should be no reason to mount it on the fresh air side rather than on the path used by blowby gases. What you want is preventing gases from igniting in the manifold etc, right?

Here is a description of my stock PCV system:
---------------------------------------------
An oil trap is fitted against the engine block. Blowby gases exiting the crankcase first go to this oil trap to be condense (like in our oil catch can). A return line let condensed oil run back in the sump. Now there is one PCV hose that runs from the top of the cylinder head down to the oil trap. A second PCV hose (the major one, 1cm diameter) goes from the oil trap right into the air intake duct BEFORE the throttle body. However there is also a very small hose (3mm diameter) that is plugged to the major PCV line too and is connected to the intake manifold thus AFTER the throttle body.

My understanding is that at idle (butterly of throttle body is closed) the vacuum in the intake manifold is high, you have low blowby and anyway you don't want to get too much of it in the intake at idle. So the very small line only lets a small amount of blowby going into the intake. No gas goes before the throttle body because the butterfly is closed at idle and thus there is no suction before the throttle body.

When you accelerate and open the butterfly, you start sucking air before the throttle body so now blowby gases have a second way to enter the intake: direct into the manifold (via small hose like at idle) and through the connection before the throttle body. This "2 hoses system" basically does the same as a PCV valve (not sure about that but this is how I understand it) but then there appear to be no such "fresh air" supply to the PCV system. I guess this ""fresh"" air supply (to prevent seals from shrinking under vacuum) comes from the hoses that runs from the cylinder head to the oil trap (again not sure at all but...).

A picture is worth 1000 words, I'll try to make one in the future.

I don't understand 100% how my PCV system is routed and works so I may be wrong on some things above so please correct. Anyone with a normally aspirated Volvo should have a very similar design to mine and should be able to explain a lot more.

 

[kilou]

I have to add that there is always a small amount of oil in the intake duct before the throttle body. I completely renewed the whole PCV system on my car and there is always some oil fumes condensing in the intake duct so probably as I posted above blowby gases really seems to enter the intake before the throttle body as well. However you're right that this connection would also serve as a supply of fresh air to the crankcase in case the vacuum gets too high. This would thus be a 2 purposes design!

 

[yugrus]

Interesting setup. But the more I think about this, it becomes clear that even with "standard" system with PCV valve gases go through "fresh air" tube more often then I thought. That's how the butterfly valve gets oil deposits at the front...
Anyway, I'm almost convinced myself to run a home-made vacuum gauge test this weekend. Let's see what is the difference.