Crank case venting on -6 engines, puking 3.2? Options

[kdfoust]

I've been motoring around in my 3.2 conversion car and generally having a trouble-free time of it (much to my surprise). Tonight driving home from work I look in my mirror after pulling away from a stop light and just prior to NAILING it and see a plume of smoke coming out the drivers side rear of the car! (IMG:http://www.914world.com/bbs2/html/emoticons/burnout.gif) I mean this is one of those plumes you see from cars that have had something go seriously wrong. (IMG:http://www.914world.com/bbs2/html/emoticons/confused24.gif)

I immediately shutoff the ignition and coast to a stop at The Shack which is an ice cream stand on PCH north of Laguna Beach. If I've boogered the 3.2 at least I've got some nice scenery to ponder the next conversion. I'd decided while waiting for the tow truck that the next engine would be a 3.6.

I can't really see anything and everything is frigg'n hot so I just dial up AAA and sit down for a spell. After the tow truck arrives (note to self: (IMG:http://www.914world.com/bbs2/html/emoticons/icon8.gif) add a pair of those neat looking tow loops to the front and rear of the car) and we load the car on the flat bed I've reconciled myself to locating a 3.6 and decide that I'll do the conversion in 1/2 the time it took to do the 3.2 (22 days instead of 45).

Three hours later at home after having dinner and some adult drinks I decide that I'd like to acess the damages. After all if I'm gonna have to do a 3.6 in 22 days I need to get right on it. After looking EVERYTHING over it's clear that the oil came out of the crankcase vent. I hadn't terminated the hose from the vent to the puke bottle in the rear trunk so the hose was blowing oil over the place. (IMG:http://www.914world.com/bbs2/html/emoticons/barf.gif)

I think that I understand why this happened. I'd just decended a steep and fairly long hill. I reckon that during the decent the scavange pump pickup wasn't picking up much oil because it was all sloshed to the front of the engine. When I hit the level ground the oil wound up getting whipped around by the crank and other various works and puked out through the crank case vent.

Does this make sense to experienced -6 hands in the house? What other conditions should I plan on seeing this happen? I suppose this could happen during long hard cornering as well. Oh well, another lesson learned I suppose.

Later,
Kevin

[kdfoust]

Arriving at home...

[John]

Was the hose loose at the crankcase or at your breather/catch tank?

I can see this possibly happening if:

1. the hose was off at the crankcase
2. oil came out the breather
3. the oil that came out dripped down onto the header on that side.

We have run our 3.2 in the track car for the last several years (13-14) and have not had this problem. We drained the catch tank/breather once (and it had maybe 1/2 pint of oil in it). Our catch tank/breather can't drain oil back into the crankcase so anything blown into it stays there.

When you mention plume, I am assuming a large amount of smoke.

Is there oil dripping from the engine at the breather location? Did it drip onto the headers?

[SLITS]

Hi Kevin...ready for Baja? You take images that are more out of focus than the Resident Kraut (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

[kdfoust]

QUOTE (JOHNMAN @ Jan 6 2006, 08:37 AM)

Was the hose loose at the crankcase or at your breather/catch tank? I can see this possibly happening if: 1. the hose was off at the crankcase 2. oil came out the breather 3. the oil that came out dripped down onto the header on that side. We have run our 3.2 in the track car for the last several years (13-14) and have not had this problem. We drained the catch tank/breather once (and it had maybe 1/2 pint of oil in it). Our catch tank/breather can't drain oil back into the crankcase so anything blown into it stays there. When you mention plume, I am assuming a large amount of smoke. Is there oil dripping from the engine at the breather location? Did it drip onto the headers?

Yeah the hose was off at the catch tank. After thinking about it I bet it was only a 1/5 of a quart of oil total but you know how a little bit of oil goes a long way when it comes to smoke and mess. The catch tank is on the driver's side in the trunk of my car so the oil ran from the engine sheetmetal to the header.

It'll be interesting to monitor the puke tank for a while to see how quick it fills up. 1/2 pint in 13 years ain't much.

Later,
Kevin

[kdfoust]

QUOTE (SLITS @ Jan 6 2006, 08:45 AM)

Hi Kevin...ready for Baja? You take images that are more out of focus than the Resident Kraut (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

Yesh, I'm gready fuh Bha.

[john rogers]

On my race car the crankcase vents to the dry sump oil tank and then the dry sump tank goes to a puke tank. The dry sump tank catches any and most of the oil particles that are coming out of the crankcase. Thi sonly fails if I overfill the system so the vent inlet to the oil tank has oil covering the hole. It then blows the oil out to the puke tank until it is happy. To prevent the hoses from coming off I ssafety wire them on with stainless lockwire under the hose clamps so they can not get blown off. Haveing said that, I imagine your problem is in several places: first venting the case right to a puke tank instead of to the oil tank. Second, not safety wiring the hoses and connections so they can not come apart. There will be pressure in the case most of the time, you just never notice it until something like this happens.

[John]

John,

QUOTE

On my race car the crankcase vents to the dry sump oil tank and then the dry sump tank goes to a puke tank.

That would be ideal, but our dry sump tank is up front (like Kevin's).

Back in the engine comp, our vent/catch tank is mounted about where the 914-6 factory tank would be located. We mounted the vent as high as it would go and still be inside the eng comp.
We used the factory vent hose.


I believe that this is more than likely how Kevin has his set up.

[kdfoust]

Yeah this is a front oil tank car. So like John says the crank case breather goes from the crank case vent to the puke bottle directly. It wasn't hooked up on purpose cause I really didn't forsee blowing oil out the vent under daily driving conditions and I was waiting on the appropriate fitting. (IMG:http://www.914world.com/bbs2/html/emoticons/ohmy.gif)

Safety wiring the clamps isn't a bad idea though. (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif)

Later,
Kevin

[john rogers]

Well that is a fine pickle! I'd say run two puke tanks then, one near the engine and one in the trunk. I can't remember how Jim Patrick runs his as he mounts the oil tank up front? There's some picts on his web site that show it though.

[John]

From what I understand, the PMS cars running front mounted tanks, are configured this way as well. In fact, Kevin's looks to be the same brand that Jim Patrick sells. Mine are actually Patterson Enterprises as they are less money but look identical.

I am doing the same setup in my current project (as soon as I get my remaining parts and lift time). I have to get a taildragger out of my way first.....

My guess is that the oil either built up over time or you had a single glurk of oil come out the breather at one time causing your cloud. Since our breather hose runs up hill to the breather, I don't believe that much liquid oil makes it into the catch tank.