8v71 airbox drains

[Kitt]

Hi all,

Does the 8v71 need the check valves on the air box drains? They're currently draining into a trap made from PVC pipe, but I need to replace one of the 90 degree fittings in the block that broke off and figured now is the time to add the check valves if needed. What happens if the check valves aren't used?

Thanks!




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[lostagain]

The check valves are not necessary. They are nice in that they only open at a low pressure at low rpm, so they only drain fluid at idle. Without them, oily fluid spits out all the time. But if you have a catch system, it is not messy. And a little of the air pressure that the blower sends to the cylinders escapes out the drains, but it is not much. So you could install them, but it is not urgent, and the engine runs fine without them.

JC

[bevans6]

I like to have them, but as JC says, they aren't mandatory.  I expect they came along as part of an emissions upgrade.  If you have a turbo engine, they become a lot more important, I would definitely install them in that case.

[wg4t50]

The check valve drains are more useful on a turbo engine, I used them on both non turbo and turbo toys.  I like every little horsepower I can muster, plus 1 or 2 is better than minus 1 or 2 hp.
Dave M

[Kitt]

Thanks everyone. I'm going to skip the check valves for now - one less maintenance item to worry about.


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[Tikvah]

Please explain.... what are airbox drains?  What are the check valves?  How do you do this with PVC?

Without them, oily fluid spits out all the time.

I have lots of oily fluid on the back of my bus and on my toad... is this a cure?

Please tell more.

[eagle19952]

Please explain.... what are airbox drains?  What are the check valves?  How do you do this with PVC?
I have lots of oily fluid on the back of my bus and on my toad... is this a cure?

Please tell more.

[eagle19952]

PASTED for your viewing pleasure....

[bigred]

Tell me more about the PVC catch basin!!I don't see a drain on the pipe.What happens when it gets full?? I would love to put some kind of a catch can on my 8v92 but what do you do with the oil that you catch??Obviously you can't poor it down the nearest drain ,but leaving these big oily spots on a nice concrete pad is not a very good option .My mechanic says that I need to hook my Grand Cherokee to the Prevost and go run up some mountains .He swears if I'll get that thing out and drive it like I was mad at it ,that these things will dry up,but sure would love to have a safety in place.

[luvrbus]

You can buy the Wagner catch cans for a DD a lot of older GM in scrap yards will have the Wagner can they have a web site you can order from (Wagner does).I don't why he has one on a Eage I just tie the drains into the front cross member with a breather and drain they hold a lot  .
A engine in good shape there is not much oil comes from the air box drains 

[eagle19952]

You can buy the Wagner catch cans for a DD a lot of older GM in scrap yards will have the Wagner can they have a web site you can order from (Wagner does).I don't why he has one on a Eage I just tie the drains into the front cross member with a breather and drain they hold a lot  .
A engine in good shape there is not much oil comes from the air box drains 

those are not mine i lifted the pictures...kinda foolish. but some engines need them ....

[Geoff]

I congratulate everyone for not using the "S_T" words.  If you have a lot of of oil coming-out your air box drains you have a problem, and a catch container is only a band-aid.

--Geoff