I did the Hughes Engines Kit 2 years and a couple months ago. It produced good results. I now have oil in my plenum. IDK when this started.
I happened to take the TB off because I couldn't get at the IAC. I have a new EGR and it has coded a month after install so I was cleaning up possible problems. I looked in with a light since it was open and the plenum pan is wet with oil. Its more than a sheen, looks like probably a teaspoon on the area I could see.
Has anyone had this happen?
Hughes seems to think there is source other than the plenum gasket for the oil.
What might it be? The PCV valves is maybe a couple months older than same the plenum kit. I think the oil breather on the other side would have made oil stains on the air cleaner if it were a source. It was dry when I removed it and put a new air cleaner in yesterday. Does anyone have any ideas where oil might come from if the plenum is good?

Edit
I used blue locktite on the plenum bolts when I torqued them.

 

May still be the PCV valve; you'd be surprised how much that sucker can gulp!

Swapping from the Fram (yah, yah, I know!) PCV valve to the Motorcraft on my Cougar moved it from 1,000 miles/quart to 1,800 miles/quart. It also now has my dipstick tube unseating itself on WOT ...

Similar variance has been noted on a few other Mopars, too.

I'd still suspect the PCV and swap a Mopar PCV valve in.

RwP

 

If you have excessive blow by the best pcv valve is not going to stop that.

 

Ordered a new Mopar PCV I put a filter in the line to see if oil is getting by.
The new Mopar PCV valve will be in tomorrow. I can't imagine that much oil is blowing by. Its only got 147K. Lets hope this fixes the problem. I started it for a couple minutes after putting the filter in and nothing obvious showed up.
Here's pic of the setup. I have a second smaller hose on the ends of the filter and the clamp holds it to the PCV hose. Pressure fit would probably work.

 

I put the new PCV in and took the throttle body off to spray the intake down with carb cleaner and wipe it with a rag. I used a paint stir stick and a wire coat hanger.
I noticed the new air cleaner had an oil ring around its top and bottom seal making me think the old after market one might not have been sealing and letting oil from the breather by over the top and bottom. I am going to replace the breather and put a clear filter in that line for the same purpose.
Here are a couple before and one after of the intake and plenum through the TB holes. I shot some more cleaner at that spot on the side wall. Edit- I got the new breather and added the filter. last pic I expect if it is coming from there I will have to wait for the new breather to get full and let oil past it. I disconnected the breather when I went to the parts store and it drove a lot better. I mean it was more responsive. I expect it was the cleaned plenum that did this.

 

Update
The filters worked. It seems the oil is getting by the crankcase ventilation on the driver side. I had installed a new vent when I placed the filter in the line.
I checked today since I have been getting a spot under my truck over the last few weeks. Something around the bottom of the TC cover seems to be leaking it looks dry above that. I wiped it down will go wash it and then check daily until I figure it out. I had put in a new seal when I did the Timing chain and plenum kit.

here is a picture of the filter. I opened the air cleaner and it had oil where it seals to the top and bottom. Feedback would be helpful. I was hoping to get the suspension and steering parts replaced before I had to rebuild. Since so much has gotten by in 24 days I'll go ahead and say the plenum kit did not fail and the oil was getting around the aftermarket air filter I had in before I changed it on the first.

 

I have deduced that the oil drip must be due to the restriction caused by the filter I put in the oil breather line creating back pressure. I have added Risolone. I'm going to continue fixing the chassis and interior before I rebuild the motor.