Log in

View Full Version : AOS drain directly to the oil pan



Dave 53
06-30-2021, 10:01 AM
Just installed a Killer B oil pan (and arctangent oil control plate) last night and haven't added oil yet. A light bulb went off in my head the moment I woke up this morning. Wish I thought of this before the installation, but maybe it's not to late... AOS drain directly back to the oil pan.

Is having the AOS drain directly back to the pan a silly idea? I can't think of any reason not to. The AOS came with a fitting to share draining duties with the PCV crank case fitting, but I haven't used that fitting because I haven't had my BAR inspection and I'm sure it would raise a red flag. Currently, I'm draining into a jar. Draining directly to the pan seems better than sharing the PCV crank case fitting.

What if I tap a fitting into the oil pan for the AOS drain? I think the Killer B pan is plenty thick enough to thread in a barb fitting.

I don't have any material to do an experiment and I really don't want to pull the pan back off. If I drill and tap a hole, most of the cuttings will come out the drill side of the hole, but how much will fall into the pan? Since the pan has never had any oil in it, I'm thinking I could vacuum out any cuttings through the drain holes.

Another option is to tap the extra drain plug (Killer B oil pan has 2 drain plugs). Advantage: Can be done on my work bench, not permanent. Disadvantage: For some reason, it doesn't seem as elegant. Maybe I'll tap the plug and live with it for a bit. Has anyone done this...tap the extra drain plug for AOS draining?

Update: Just rummaged through my shoebox of fittings and found a 1/2" NPT plug already tapped with 1/8 NPT hole! Going to buy a lottery ticket today!

Sgt.Gator
06-30-2021, 10:40 AM
The following is my opinion, I haven't actually done what you are thinking, although I do have experience with the KB pan.

I would NOT drill into the pan while on the engine.
The only reason I see not to use the second drain port for an AOS return is having an oil line/hose that low to the ground where it could get ripped out, which could be catastrophic.
So I would either run the return the usual way in the AOS instructions, or remove the oil pan and tig weld a bung higher up on the side, above the normal oil level.

Dave 53
06-30-2021, 06:07 PM
I'm not sure how a hose from the drain plug leading up could get ripped out. But, I am VERY concerned about the entire KB pan getting ripped out as it hangs below the chassis rails! I'll start a new thread on that subject...

Bob Cowan
06-30-2021, 08:13 PM
Just installed a Killer B oil pan (and arctangent oil control plate) last night and haven't added oil yet. A light bulb went off in my head the moment I woke up this morning. Wish I thought of this before the installation, but maybe it's not to late... AOS drain directly back to the oil pan.

I would not recommend that. Along with oil vapor, the can catches water and other airborne crud.

This is what comes out of the catch can on my diesel truck. I wouldn't pour that back in my engine.

https://i.imgur.com/FJibtu0.jpg

https://i.imgur.com/f9KVCzu.jpg