Venting crankcase to atmosphere

[belfastguzzi]

ok, sorry these pictures are a bit disgusting. They show the water - emulsion that returns to the sump oil:

 

The pipes and the spine frame are thickly coated with creamy emulsion. In the bottom of the spine there is a pool of water that can be seen through the outlet that feeds this water into the sump oil. Yuk. It was hard to get a photo. You can see the line of the top of the water. Angles are funny because the bike is leant over. In the jug is some of this water extracted from the spine. Now you know where to find this, no need to carry a drinks flask in future. Just remove the banjo bolt in front of the tank and drop in a few spoons of coffee powder or instant soup.

 

Is this system really necessary? Why not disconnect the breather where it enters the spine and let the water vapour vent to atmosphere instead of recirculating. Is there too much oil being vented for this to be a reasonable proposition? Is there a reason the vent system has to be closed (apart from environmental considerations)?

 

Sometimes I have disconnected car breathers instead of having them recirculate, particularly when a core plug went in the Land Rover engine (– until I repaired it). I collected the condensed vapour in a bottle. It was basically all water, I don't remember much or any oil.

 

As a first step, I have vented the outet pipe from top of frame to atmosphere and closed off the airbox feed. I'll see if any / much oil shows out of this top vent and how much water is expelled. The next step would be to rearrange that engine case breather, before it gets to the spine frame. (Water in the steel frame can't be good thing anyway.)

 

Any good reason not to do this? Pete? Rubber chicken?

[belfastguzzi]

Maybe another option is to put a drain into the spine where the water collects, so that there is not so much returned to the sump?

[guzzi323]

In one of the other oil consumption related threads, Pete Roper speculated that our disappearing oil might be going into the airbox through the spine vent. Perhaps we should try venting into a catch bottle instead of the airbox. Then we'd know if our oil was getting burned up through this route.

On my bike, usually by 4k miles on an oil change I have to top it off with 1/2-3/4 quarts of oil. It's not leaking out so It's got to be burning up. Next time I've got the tank off, I think I'll rig up a catch bottle and we'll see how efficient these air/oil separators are.

 

johnk

[belfastguzzi]

Hi John

that's what I've done. The vent that I've described above is the one that goes to the airbox.

 

There are two ways that the oil/water vapour & liquid can go: out to the airbox and back down to the sump. I know that oil mist does go to the airbox, but I'm hoping that mostly water vapour goes there to recirculate back into the engine and so taking this pipe out of the system will let water out, rather than oil. We'll see.

[jrt]

The old loopframes vented almost straight to atmosphere- they went through a (useless) recovery box, so the idea has possibilities.

That won't fix your root problem, though, which is that your bike runs too cold to evaporate off the condensate. I'd think about restricting airflow around the cylinders to keep the bike warmer.

[Guest Nogbad]

Yuk! Given that oil floats on water, if the wet crap makes its way back to the pickup, thats what will get sucked up first, although there should be a lip around the strainer or ribs in the sump to prevent flow of the bottom half inch of depth or so to stop exactly this happening.

 

The fact is, you are not running the bike for long enough at a time. I had a look inside my spine, nothing but a light oil coating. But then, my bike gets started, then a 50 mile thrash, then stopped until a repeat at the end of the day.

[belfastguzzi]

Yuk! Given that oil floats on water, if the wet crap makes its way back to the pickup, thats what will get sucked up first, although there should be a lip around the strainer or ribs in the sump to prevent flow of the bottom half inch of depth or so to stop exactly this happening.

 

The fact is, you are not running the bike for long enough at a time. I had a look inside my spine, nothing but a light oil coating. But then, my bike gets started, then a 50 mile thrash, then stopped until a repeat at the end of the day.

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yes there was plenty of emulsion around the pick-up. I suppose it makes a bit of a nonsense of the 'what oil, exactly, should I use?' concern. Make mine a capuccino.

 

Actually I prefer espresso. Good to hear that there is only a coating of oil in your frame. So cutting out repeated short journeys is the real answer: though I'll still experiment with the plumbing routing. Do Gaggia do aftermarket parts?

[Guest Nogbad]

yes there was plenty of emulsion around the pick-up. I suppose it makes a bit of a nonsense of the 'what oil, exactly, should I use?' concern. Make mine a capuccino.

 

Actually I prefer espresso. Good to hear that there is only a coating of oil in your frame. So cutting out repeated short journeys is the real answer: though I'll still experiment with the plumbing routing. Do Gaggia do aftermarket parts?

54412[/snapback]

 

You could make a small catchpot to put in the return line from the frame to the sump. This is basically a little chamber with an inlet pipe that dips almost to the bottom, and a weir or baffle behind which an outlet port drains the contents. It makes use of the fact that the water will gather at the bottom, and you put a little drain plug at the bottom to remove the water periodically.

 

I might try making one.

[belfastguzzi]

You could make a small catchpot to put in the return line from the frame to the sump.

54413[/snapback]

I would prefer to catch, or lose, the stuff before it gets to the frame.

 

If I was to do something with the return from the frame, I would be tempted to open the pipe and close the sump and just not return anything.

 

 

The reality is that most of my weekly journeys will be short ones, so the oil is not going to get a good roasting. Although I didn't consider the issue in great detail, I had previously thought that the air-cooled motor would heat up quicker than a water cooled and so be better for short journeys.

 

I can't be the only one who does short 4 to 5 mile journeys – or am I?

 

I wonder if any of the modern car engine technology has tackled this issue of constant short cycles where the engine & oil rarely gets up to temperature?

[txrider]

Some thoughts and observations concerning engine warm up and operating temps-

I have an 11 year old Volvo 850 that apparently has a cooling system designed to come up to temp fairly quickly. Coolant temp shows normal within 5-6 minutes although I'm sure the oil temp takes somewhat longer. It seems to me that water cooled engines have more control over rate of heating up and possibly stabilized operating temperature due to thermostat controls in the cooling system. I can't name the source, I've forgotten it, but I read recently where an air cooled (Norton)bike engine oil temperature was still stabilizing after 10-12 miles of medium speed operation. So, with aircooled engines we don't have a lot to play with in engine warmup control except to block off cooling fin area which, unless done with aid of careful cylinder temperature measurement could cause other problems like uneven cylinder temps and maybe even cylinder distortion.

I think installation of an oil temperature gauge and a sending unit properly placed in the pan could at least provide information of when and if the oil gets to minimum of 212f for moisture boil off. If driving conditions don't allow this temp then the suggestion of buying a Japan made beater bike sounds like a good approach.

In fact I'd be interested to know if anyone has installed such a gauge and if so how they did it. I'll bet some of the experienced gurus like Pete Roper have done this to monitor engine oil temps in racing.

[Skeeve]

The reality is that most of my weekly journeys will be short ones, so the oil is not going to get a good roasting. Although I didn't consider the issue in great detail, I had previously thought that the air-cooled motor would heat up quicker than a water cooled and so be better for short journeys.

.....

I wonder if any of the modern car engine technology has tackled this issue of constant short cycles where the engine & oil rarely gets up to temperature?

54447[/snapback]

 

Plan A: if all your journeys will be short, start the bike before putting on any of your gear & leave it idling while you gear up; the time spent running on the sidestand will add to the time of your overall heat cycles.

 

Plan B: get a 1-way valve & run the breather to the airbox & be done with it. Any oil vapour gets burnt, the water vapour adds minutely to your power, and you only have to be diligent about checking your oil.

 

Best o' luck!

[belfastguzzi]

I have an 11 year old Volvo 850 that apparently has a cooling system designed to come up to temp fairly quickly. 

54456[/snapback]

 

Synchronicity or what! The newspaper in the photo in this thread has an ad for – a Volvo 850!

I just have to hoke through the bin, find the paper, a bunch of old tenners...

[big J]

I'd agree with Skeeve, a 1 way valve into the airbox would work ok. Or get up half an hour earlier and go for a decent run before work,skiver. Just because you're Lord Mayor doesn't mean you can lie in bed half the day. If you're stuck, get one of your flunkeys to take it out, or drop it off here, I'll do my best to fry out any emulsion.

[belfastguzzi]

54467[/snapback]

I'm gonna run it on Scotch Whisky. Then the water can only improve matters.

[big J]

WHAT? Water in your whisky??! Are you mad????