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2.5 NAD-oil breather back into intake manifold

boulder_rover

boulder_rover

In Fourth Gear
Hi everyone,
2.5 NAD in 1972 Series III
I am currently routing my rocker cover breather hose back into the intake manifold (there is a little port in the middle of the manifold that will accept the hose). My engine is not a heavy breather. I got tired of it dripping on the driveway and had the place to connect it........

What am I going to mess up by doing this? Truck seems to run the same, vented to to air or the manifold. I am wondering about the suction created by the intake manifold? Truck does not run on when cutting fuel off, which I thought would be one problem (burning up the oil vapors).

Thanks
 
Use a small sized pipe and try to put a gauze trap in the line. You just need enough depression to draw the fumes out. Too big a pipe and no trap, you will draw oil from the rockers if you run the engine hard for a long distance.

Chris
 
There was a modification on the military 2.5 N/A engines which returns excess oil/fumes from the crankcase to the sump from the rocker cover and any crankcase fumes are drawn into the inlet manifold. This is a standerd fitment on reconditioned engines used by the Forces. The engine is called a MK6B. I think the problem was that the old breather set up, dumped oil into the air filter and made it a nice oily mess with the chance of the engine running on it's own oil to destruction.
 
Dave,

That sounds like my truck. Ex-MOD RHD Series III. I always wondered if the engine was swapped here in the USA or if it was done by the MOD. I also have a little brass pipe brazed onto to my oil sump. It is directly opposite the drain plug, and points upward. I keep it capped off. Any idea what this is for? Should I route a hose from this up to the manifold? If I take the cap off, oil pours out so I wouldn't want to suck oil up into the manifold.


Thx
 
Yup, my mil 2.5 NAD has a cyclone filter in the breather pipes. However, mines a winterised / wader, and I can only find mention of the filter in the wading prep manual.

Nige
 
boulder_rover,

The fitting on the sump should have a pipe that runs up to a cyclone filter and a depression valve. There should be a hose from the rocker cover cap/breather which leads onto the cyclone which lets oil return to the sump and lets the gasses be drawn off through the depression valve to the inlet manifold to be burnt. This is all in the military modification book for engines that are being reconditioned, the plan was/is to make all the 2.5N/A engines to one build standard and under one part number so that they are interchangeable between all 90/110 Land rovers. I could look up the part numbers if you feel that you want to put all the missing parts back?

Dave
 
TEMPL4R said:
Use a small sized pipe and try to put a gauze trap in the line. You just need enough depression to draw the fumes out. Too big a pipe and no trap, you will draw oil from the rockers if you run the engine hard for a long distance.

Chris
Click to expand...


Yep, I can vouch for that...I had that on a 2.25d. It had a pipe running from the filter on the rocker cover to the inlet manifold. It ran fine most of the time but would suddenly started knocking like the clappers and smoking like a smokey thing on a long fast run. It took me a while to realise what the problem was as it was fitted by the P.O.
Cya
Mungo:)
 
Ok, I got the cyclone gizmo now and am wondering how to plumb it up. There are three ports on the cyclone. Bottom one obviously goes back to the sump. That leaves two on top. One has an o-ring bushing, the other does not. Right now I have the rocker cover breather going in to the top port, and the cyclone to intake manifold out of the middle port.

Thanks
 
I'm replacing the head gasket on a 2.5 N/A at the minute. Pipe goes from the filler cap to a short stubby pipe that sticks out of the inlet manifold. The filler cap has an oil seperator/gauze filter inside it.
 
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