Air Intake Filter cleaning

[Traveler 45C]

Hello All,

The filters on my 8V71N’s are the foam type that wrap around the Air Intake. As these are not covered in the Service Manual, I don’t know the proper way to clean them. The Crank Case vents to the intakes and the filters get very oily (Yuk!). Should these filters be cleaned with F/O or a detergent?

Also…

As you can imagine, the intakes are excessively oily and full of crud, a gift from the previous owners. I’ll need to pull these as well as the Blower Screens and clean them also. My concern is for the Air Boxes. If they are fouled up, how can I get them cleaned? I read somewhere that shooting a mixture of Dawn and water into the intakes @ cruise RPM will clean Turbo Blades. Will this procedure also clean the Blower and Air Box? Is this really a good thing to do?

Thanks in advance,

G

[Genesis]

Clean the filters with detergent. If that doesn't work, try Zep 505. That WILL clean sooty and nasty parts, but be careful with it and make sure you rinse it all out!

As for "turbo wash" that is often touted on Boatdiesel, I'm not sure I'd trust it. I know that there are folks over there who say its good for "any diesel", but consider this - what if the wash manages to break off a good-size chunk of "crud" that then goes into a cylinder and is larger than the space at the top of the piston on the compression stroke?

I'd love to avoid having to tear off the top of the motor (blower, etc) and do this job manually, but can it really be SAFELY avoided? I dunno. This much I *DO* know - the folks who advocate this method won't buy you an overhaul if you do it and it trashes your engine.

[Traveler 45C]

Thanks Genesis.

I guess I'll make the decision whether to pull the Blowers or not after I get to the screens. Hopefully the screens have caught most of the crud. If the Air Boxes are just oily, do I need to get in there and clean them out or am I just chasing my tail?

G

[Genesis]

The screens are really more like chicken wire, unless someone has changed yours. They're only intended to prevent "big things" from going into (and destroying) the blower.

[dshuman]

Air-Seps sure fix that nice. Engine room stays clean too.

[Genesis]

.... BITE!

Walker has done two things that are REALLY STUPID with their design:

1. There is no positive filter on the crankcase effluent before it goes into the intake. No, that mesh in there (which you cannot get out to clean) doesn't count. Speaking of service, how do you clean that? You don't. Do you really want to return that to your crankcase? Hmmm...

2. The vacuum limiter design bites severely. Worse, its not cleanable, because Walker was so nice as to rivet it closed. And there is no way to know if its sticking or not other than to remove and tap it - which you really ought to do before EVERY run. If it sticks, you will develop a LOT of crankcase vacuum, and pull over a LOT of oil. Maybe enough to run away. Certainly enough to cause problems - like fouled inter/aftercoolers.

3. K&N makes the filters. Walker uses a funny size and got K&N to agree not to sell the elements to anyone other than them. They then mark them up about 500%, which of course you pay. Nice eh?

Try the Racor CCV system instead. Its cheaper and the stupidities that Walker displays are addressed in their design.

If you MUST run Walkers (you have them already, and don't want to spend on replacements) then make damn sure the vacuum limiters are not sticking - check them before EVERY DAY of operation, and route the returns somewhere OTHER than your crankcase (e.g. to a crap can) That way you won't pollute your crankcase oil with sludge and you also won't eat your oil supply up through the intakes.

[dshuman]

Genesis,

Thanks. Good to know if there are things I should watch. I see Air Seps listed on half of the 1510 Hatteri and Detroit Diesel thinks they're OK so I'll probably keep mine and watch them closely. How do you check the vacuum limiters? There's an air restriction gage on the air-sep and a check valve in the oil return line, which I presumed are there to prevent over-vacuum from sucking up oil?

Doug

[Genesis]

No, the vacuum gauge only shows you how restricted the main air filters are. It does not indicate proper operation of the crankcase vacuum limiters.

Proper maintenance of those things is critically important if you want to keep them. Make very sure the the vacuum limiters are free before EVERY run, and check the return check valves regularly (every oil change interval or six months). Air filter elements of course must be kept clean as well, but that's true for any air filter element....

If the vacuum limiters ever stick on you or their small filters get dirty, they must be replaced immediately.

[dshuman]

Genesis - Thanks. How do I check the vacuum limiters? As you say, they're sealed shut. If I shake them (in place) I can hear a rattle inside.

Doug

[jim rosenthal]

Not only are the K&N filters way too much money for what you get (and you can ONLY get them thru Walker), they restrict the airflow too much. My engines run better with no filters (not that I do this but we found this out by accident when we were running the boat and measuring boost etc). I am looking into the Racor CCVs also. I think Walker are snake oil sellers. Have you seen the FuelSep?

[jim rosenthal]

Karl, what is involved in converting my engines from Airseps, which I added on, to Racor CCVs? I have CAT 3116s, the 350hp version. I think I saved the factory airfilter housings but I am not sure. Any thoughts on this?
My email is Jimbo1907@comcast.net.

[Genesis]

The Racor system includes new air filter housings as well as a different CCV design. Boatdiesel.com sells 'em (no connection, but they have nice prices)

[jim rosenthal]

OK, I looked at them...it appears if I've done the math right that CAT 3116s would use the smallest size CCV, they are rated at 350hp, which would be about 5.8 cfm. Any thoughts on this? I am going to order them this week. I will sell the AirSeps on Ebay, someone may want them.

[Genesis]

I might go up one size on the air filter... probably not a bad idea to talk to Racor about it first...