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Catch can for Blow-by?
The crank case ventilation system for our Series 60 is set up the old-fashioned way. Simply a hose to the ground.
At last year’s trip going up to Flagstaff (7000′) which requires full throttle high RPM for an hour or so, I noticed some oil droplets on the back of the bus. Clearly, high elevation, full throttle and high RPM increases blow-by. I normally don’t see any oil droplets when I cross the Siskiyous (4500′) or other hills of that magnitude.
I was thinking about installing an oil catch can. Has anyone done that? The can from Moroso seems good quality.
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15 Replies
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Makes sense to me. Can you mount it in a place it will be readily accessible? I’d probably plumb it with aviation/motorsports grade braided stainless hose and aluminum AN fittings.
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I’m curious as to why. I have had several jaunts in that area and made hard long distance climbs and never sensed blow-by.
I would want to find out what is causing the problem in the first place, assuming it is a non-issue elsewhere in your travels.
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Noticing a drop or two of oil on my garage floor coming from my crank case ventilation tub at the end of each trip. Inquired about the drips with Ocala, Fl Detroit Diesel, service manager said it could be the rings in the air compressor going bad and causing pressure in the engine, hence the oil droplets.
Don’t know if I accept that theory, anyone have additional thoughts?
Chuck
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A few drops from the tube is normal, every one I’ve had did it.
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My dogs and my DD60 always mark their territory. They don’t call it a “slobber tube” for nothing.
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Well, the engine is 21 years old with 185,000 miles. The blow-by at high load could be due to increased wear. But the engine does not consume oil between changes, there is no blue smoke on acceleration and when I open the oil filler at idle, there is no pulsing oil mist which would indicate a problem with a single cylinder. So, my take is the blow-by is within acceptable parameters. It is just more visible on these pre-EPA engines.
I understand there is a metal mesh in the valve cover to trap the oil before it gets to the slobber tube. I’ll have to take a look and see if I can clean that mesh without taking off the valve cover.
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The age of the engine is unimportant and 185,000 miles is not even 20% of its life. If it is not using oil between changes that makes the cause for blow-by a bit more of a mystery.
If you were burning oil I would be inclined to suggest some cylinder pressure is getting past the rings and pressurizing the crank case but that doesn’t seem likely.
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My 12.7 breathes some too. What’s funny is that my old 8V92T did not show any breath and did not drop a bit of oil on the ground. It did use oil either. Unlike every other Detroit Diesel engine I have ever owned like they were all supposed to do. Go figure.
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You can hang a picture of a detroit diesel on the wall, next morning there will be an oil spot on the floor
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“You can hang a picture of a detroit diesel on the wall, next morning there will be an oil spot on the floor”
I just spit my coffee on the keyboard!
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Just be glad you don`t owe a new Volvo engine !!
1999 XLV X-6872, liberty #440 -
I know from several PC members the early Volvo engines caused a little intestinal distress almost exclusively due to emissions and the ECM. However once past the infancy stage even the early Volvo engines, and certainly the later models have been superb. Better mileage, quiet and plenty of power.
Looking back on the 8V92, it sure sounded sweet, but there is no way I would ever want a 2 stroke. I would however long for a pre-emissions Series 60, an economical engine with no downside.
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When I bought my coach at 6 years of age and about 45000 miles, it would emit visible smoke from the breather tube at idle. I was told this was not unusual and it’s possible the rings were not yet properly seated due to it’s low mileage. Possibly BS but the smoke bothered me.
I installed a positive crankcase ventilation device designed to filter the air from the valve cover, separate the oil and return it to the oil pan and the cleaned air routed to the intake tract. As I installed it, the cleaned air is discharged to atmosphere but it’s still emitting less emissions than stock and I don’t see smoke. Engine uses about 1 gallon of oil/10,000 hard miles. Current mileage is about 240,000. The downside is that I am replacing the filter element with every oil change (10,000 mi) due to contamination and the element is about $100.
Can’t remember manufacturer/model # but if anyone is interested I can dig out my info……ding……Donaldson spiracle
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I would like to know the manufacture and the model number thanks
1999 XLV X-6872, liberty #440 -
I don’t think my model # will do you any good now…superseded. Donaldson spiracle…largest available for class 8 trucks.
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