Installing Walker Airseps on Detroit 8V-71N

[drewread]

With the loss of boatdiesel.com I'm hoping there are enough people here that we can get some Detroit answers on this forum and hopefully build up a bit of an information archive that will be usable.

I'm preparing to install Walker Airseps on a new to me 1972 Hatteras 48 Yachtfish when I can finally get to her in the spring, she is all wrapped up now and I'm forced to plan based on the photos I took during the purchase process.

I managed to find some brand new old stock Airsep kits with their installation manual, and I also have a copy of the latest version of the the Airsep installation manual for a 8V-71N. The only difference between them is that the old one has a PR2000 vaccum assembly on each "engine breather" then they tee together and head into the Airsep. The new instructions tees the breathers together and then there is one PR2000 after the tee before it heads into the Airsep body.

The issue I'm having is trying to find the breather tubes to connect them to based on my engine photos, as mentioned I don't have access to the boat but I do have some photos. I can only seem to find the flywheel breather tube in the photos and that is the one I am supposed to plug up and not use.

Am I correct in thinking that I may not have the other two breather tubes installed on this engine or am I looking in completely the wrong location? Images below.

Thanks for any help!

I believe the green circle is the Bell Housing Breather which routes up under the existing Air filter into open air. This may be my only engine breather.

The green circle is where I believe one of the "engine breathers" should be, the hole below it to the right in the picture is potentially a closed up "crankcase breather" location. Correct me if I am looking in the wrong place.

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[Captain Ralph]

The top picture is your crank case vent (cam gear cover on engine back with pipe pointing up). It offers a mesh to coalesce oil for return back to the engine and allow fumes to pass to your air intake assembly.
With out the normal valve cover breathers, this will be your best option.
Your bottom picture, that lil port in the head, IMO is not going to help but just make a mess.

Question; Why do you feel you need a Walker system on a natural V8 when your already venting/drawing into the air silencer?

 

[drewread]

Thanks for the reply Capt Ralph.

In all honesty, I don't have any time on the vessel as I purchased it late fall and stored it. I'm trying to prepare for some maintenance that is overdue in the spring. This is just one of many projects, don't worry there will be lots more silly questions!

There is a stream of oil running out of and down that crankcase breather tube, you can see some in the image of it. It may be coalescing on the foam air filter material and dripping down. It is not all being taken care of by "almost" entering the air intake. The Airsep should run that oil back down to a crap can through its discharge hose and stop if from getting into my bilges.

The air filters needed replacement regardless, so this hopefully takes care of two birds with one stone.

 

[Captain Ralph]

So, Your vent pipe (#2 in picture) just stays outside the engines air filter/silencer can and not in to it. Inside the gear cover (#1 in picture) is to be a mesh to capture that oil before it blows way up that pipe. You may want to check into this.
Do you have a manual?

 

[drewread]

So, Your vent pipe (#2 in picture) just stays outside the engines air filter/silencer can and not in to it. Inside the gear cover (#1 in picture) is to be a mesh to capture that oil before it blows way up that pipe. You may want to check into this.
Do you have a manual?

Yes, it sits open just below the foam air filter (image below pipe #2).

If you look closely you can see that the foam filter is hanging about 1/2 inch off the bottom of the filter housing. Without being able to see it in action, my belief is that oil (vapor?) is leaving that tube and getting sucked into the foam filter, coalescing on the foam and dripping all over that end of the engine.

It is almost an airsep style setup, just not quite hitting the mark.

All of these are reasons I wanted to install the Airseps.

I do have the manual and noted that the "Flywheel housing breather" has a breather pad (wire mesh filter) inside of it that is supposed to be periodically cleaned. I doubt it has been cleaned or checked since the engine was overhauled in 2010. I plan to clean it once I find the gaskets for it.. as long as it is not going to get capped off as the Airsep instruction sheet suggested is was supposed to be.

 

[Captain Ralph]

Your term; "Flywheel housing breather" still bothers me.
This is not the flywheel housing.

With out valve cover vents, this is the only block vent you have and should never be blocked off.

That is an ugly pipe end. Almost like it has been cut short or something is missing?

 

[Captain Ralph]

BTW; I have a same rear gear cover/vent on my 12V71TIs and valve cover vents.
I wonder what was stock on your engines.

 

[drewread]

Your term; "Flywheel housing breather" still bothers me.
This is not the flywheel housing.

With out valve cover vents, this is the only block vent you have and should never be blocked off.

That is an ugly pipe end. Almost like it has been cut short or something is missing?

From the manual:

 

[drewread]

BTW; I have a same rear gear cover/vent on my 12V71TIs and valve cover vents.
I wonder what was stock on your engines.

No options plates and an out of hull rebuild in 2010.. So I will probably never know

 

[Captain Ralph]

No options plates and an out of hull rebuild in 2010.. So I will probably never know

Crazy, Yep, it is called a flywheel housing in my book also.
I have been wr,,, I have been wro,,
I have been incorrectly referencing that part for a long time.


With the serial number, a real DDC shop can print out the factory option / build data.
Maybe be able to retrieve the tag data. I don't think they can print new tags anymore.

With the serial number, a whole part number manual (including every washer and nut) can be ordered. This offers everything the engine was built with.

 

[Sonic Boom]

Don’t plug that crank case vent, if you think a Detroit leaks oil normally just wait till it can’t breath. It will find a gasket to breath out of. That plate on the inside of the head usually has a pipe to drain oil/gas back to the case and there’s a hose that eventually leaks in this location. Maybe a blessing you don’t have this as its one less thing to leak and not the easiest location to repair.

 

[drewread]

Don’t plug that crank case vent, if you think a Detroit leaks oil normally just wait till it can’t breath. It will find a gasket to breath out of. That plate on the inside of the head usually has a pipe to drain oil/gas back to the case and there’s a hose that eventually leaks in this location. Maybe a blessing you don’t have this as its one less thing to leak and not the easiest location to repair.

I have no plans on plugging my only breather, it looks like it will be the only breather routed to the Airsep. I think that is where this is all headed at this point.

I was trying to figure out if I had the other two breathers and was just looking in the wrong location for them, but at this point I don't think I am.

 

[drewread]

Crazy, Yep, it is called a flywheel housing in my book also.
I have been wr,,, I have been wro,,
I have been incorrectly referencing that part for a long time.


With the serial number, a real DDC shop can print out the factory option / build data.
Maybe be able to retrieve the tag data. I don't think they can print new tags anymore.

With the serial number, a whole part number manual (including every washer and nut) can be ordered. This offers everything the engine was built with.

I'll take recommendations on a DDC shop that can pull that info. Up here in the great white north we are always referred to Wajax by DDC. They so far have not been helpful.

 

[bostonhatteras]

The 'lost' second vent is the freeze plug just to the right of the circle on your cylinder head. I've seen some engines with it and some without it. I went completely redneck for this crankcase venting. I drilled and tapped a 1" nylon threaded barb into the emergency shut down housing on the tubular part just before the turn to the silencer, then added braided hose to a tee that connects the crank case vent and the rear of block vent. The braided hose is clear and its remained clear for 8 years now anyway, so little oil goes through it. poor mans CCV but it works perfectly with taking up little space or expense. I can post pics if you care to see it, much less hassle than airsep

 

[cww]

This was never popular on the naturals which is the reason walker stopped selling the kits for them, I don't think they ever sold more than a handful. Not sure of the science behind it, but the boats I've had with naturals the ER always stays clean on its own. It's the turbo ones that soot everything up without them. I wouldn't bother with it on naturals, it's a solution in search of a problem.

 

[drewread]

The 'lost' second vent is the freeze plug just to the right of the circle on your cylinder head. I've seen some engines with it and some without it. I went completely redneck for this crankcase venting. I drilled and tapped a 1" nylon threaded barb into the emergency shut down housing on the tubular part just before the turn to the silencer, then added braided hose to a tee that connects the crank case vent and the rear of block vent. The braided hose is clear and its remained clear for 8 years now anyway, so little oil goes through it. poor mans CCV but it works perfectly with taking up little space or expense. I can post pics if you care to see it, much less hassle than airsep

Looking at the manual, that was one vent option, "cylinder block breather". Other breather options were the two plated over holes (I circled one in green), the "cylinder head breather", and valve cover breathers. One option in the manual has the two cylinder head breathers tied to the cylinder block breather with hoses and a tee. Lots of variation, but not clear why various options were chosen - I'm confident there are some grey haired mechanics that know exactly why each one would be beneficial in any given situation.

 

[drewread]

This was never popular on the naturals which is the reason walker stopped selling the kits for them, I don't think they ever sold more than a handful. Not sure of the science behind it, but the boats I've had with naturals the ER always stays clean on its own. It's the turbo ones that soot everything up without them. I wouldn't bother with it on naturals, it's a solution in search of a problem.

I'm not sure they were as unpopular as you may think, and definitely more than a handful were sold as I have two in my possession and that only leaves three fingers.

I'm not at all concerned with soot, I'm concerned with getting oil mist under control in the ER, which is exactly what the Airseps were designed to do.

FYI - they are still for sale and supported by Walker. These were used on more than boats as I'm sure everyone is well aware.

 

[jmooney]

Could you find valve covers with vents ? This would be much like the later engines and maybe easier to plumb .

 

[Timeless72]

I installed airseps on our 871s several hundred hours ago. Noticed an immediate decrease in leaks and they run quieter. Maybe a different tone over decibel. For what it's worth, would do again. They are naturals.

 

[Captain Ralph]

Here is a pic of the vent pipe coming out of the block's rear cast. This gets in the way of many options.