Educate me please... Breather to Turbo oil

Boat Guy

Boat Guy

Well-Known Member
May 15, 2013
2,289
Who knows? Could be Cali, Oahu, Florida, Annapolis
Boat Info
400 DA
Engines
CAT 3116s
So, on my Cat 3116 I have a breather with an exit pipe that goes around the engine and exhausts near the air intake filter on the turbo.

So the engine room gets oil as well as oiling the filter and I guess lubricating the turbo a bit...

How important is this lubrication to the turbo? It's got an oil line running right througth the center housing lubricating the shaft.

Why cant you run a hose from the breather exhaust pipe to the oil fill tube?
 
The canister in the center of the engine is a crancase vent filter. The crancase fumes, which contain oil droplets, pass thru it and around to the AirSep in the black corregated tube. The AirSep has a turbine feature in its design that slings (for lack of a more desctiptive term) the crankcase vent fumes outward and causes the oil to precipitate out of the crankcase fumes which is then recirculated into the intake stream. The precipitated oil then drains out of the AirSep back into the oil pan.

By passing the AirSep means you will be dumping the engine crankcae venair/fumes back int ot he engine which can only increase crankcase pressure and increase blowby, increase oil consumption and decrease efficiency. If you wish to eliminate the plumbing and thereby negate the purpose of the AirSep, then remove the large corregated black hose where it enters the AirSep, blosk off that orifice on the AirSep body and hang the hose down into the lower part of the bilge then put several oil absorbent pads under it because it is going to make an oily mess.
 
Frank, somehow I figured you'd be the one responding....Thanks.

Thing is, for some reason, my '97 doesn't have airseps. If it did I wouldn't ask the question. Mine has a pipe off the crankcase vent filter that just ends on the stern side of the engine and blows into the engine compartment near the std. filter.

I was thinking of adding the Airsep or looking for alternatives.

I did think going straight back into the oil fill would increase pressure and the possible other contaminants wouldn't be good either. I think Walker wants $1100/per for their solution...looking for options.
 
Run a tube from the output into a plastic bottle. Then just empty the bottle once in a while. There are kits to replace the airsep units with a simple air filter, that do just that.
 
Sorry, Eric. I thought Sea Ray started requiring AirSeps on 3116/3126's in late '96 model year.

But the description above explains what the AirSep does. Putting a bucket or oil pads under the vent pipe may catch the oil that has precipitated out of the crancase vent fumes but neither approach will remove all the oil from the crancase vent fumes. You will still have an oily mist in the engine room. Routing the crancase vent directly to the oil pan won't work because it increases the crancase pressure and increases blowby, will increase oil consumption and decrease efficiency.


The other consideration is noise. The AirSep does significantly reduce the turbo noise on 3116/3126's. My boat did not have Airseps when we bought her. The first day on the boat, I couldn't get the dogs out of the cabin and the turbo whine was so loud you couldn't have a discussion with a passenger sitting beside you. I ordered Walker AirSeps the next morning.
 
That's what I heard too Frank, but mine doesn't have them...

Thanks for the info guys...I don't want to increase crankcase pressure, I'd like to lower it, which I understand that's what the Airseps do. But, was just thinking of seeing what other solutions were out there.

Are you saying it lowers the noise enough to have a conversation? It was that noticeable?
 
My wife and I can have a conversation in normal speaking voices while sitting in the front seat which is right above the turbos. The dogs no longer run to the cabin when they get on the boat and are happy sitting on the back seat at all rpm settings. The difference is more than noticable...it is dramatic.
 
No, I do not, and we are 500 miles from the boat. I can take some the next trip to Florida but it will likely be after Christmas.

Here is a photo from the Walker Engineering website that might answer any questions you may have:

https://www.walkerairsep.com/product_detail.asp?id=77

First, open the little photo of the yellow Cat engine in the upper right corner to a larger view. The OEM air breather is the black cylinder to the right of the turbo. The Walker AirSep replaces the Cat breather and mounts on the turbo inlet. The airspeed is conical in shape while the Cat breather element is cylindrical.

Also, I'll try to answer any questions you might have................



Frank
 
Thanks Frank.

I have just read your several posts around these and they certainly sound a great investment. We have noticed a whistling noise which I presumed is turbo and would be nice to eliminate.
What is the approximate cost for a set? Other than possible new hose as their website suggests, presume pretty much plug and play from an install perspective. Might make contact to see if they ship internationally.
 
Well, it is a bit more than plug and play, but is well within the ability of a weekend mechanic, and the installations with the AirSep are very good.

The factory crankcase vent system must be removed and the Walker Engineering parts installed thus making the 3116 have a crankcase vent recirculation system that captures crankcase vent fumes and separates the oil out of the vent fumes and muffles the turbo squeal because the AirSep has a muffler built into it.

There are some potential land mines in the installation that are easy to avoid if you know where they are. So, if you will let me know, via PM (to be sure I see it, not to keep it a secret) after you get the kits and read there installation instructions, but before you take anything off the engines, I'll help you with them.

As far as cost, I don't have a current frame of reference, but I would guess AirSeps for 3116's would cost $850 to $950 (US) each.
 
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