But where has all the oil gone?

The truck is drinking oil somehow.  The engine is a relatively normal rebuild, minor compression bump, light porting, rocker upgrade to increase lift, nothing extreme.

I've got no puffs of blue smoke when I start up or accelerate.  I have no stains where I park either at work or at home.  (Minor clarification, at home I have no new stains.)  The back end of the truck is relatively clean of any evidence of oil where the vortex from driving down the road would let the oil settle on the tailgate.  There is some nastiness on the back there, but it doesn't feel oily, it more feels like the regular road grime and grit that you get from driving wet roads.  The plugs are good.  Nothing weird in the radiator.  Despite all of this, I'm drinking about a quart every 1000 miles or so, if I really put my foot in it sometimes its more than that.
About the one thing that I can point to is that when I had the intake off to replace my injectors I realized that my PCV valve was sucking oil and putting it in the intake, so I ended up putting in an oil catch can.  I haven't had it long enough to gauge whether that's the culprit.  Enough oil in the intake that if I stuck my finger in and touched the wall it would come back with enough to make a print, but if I stuck my finger in as far as I could and drew it up along the wall of the intake it would form a droplet that wouldn't fall off my finger.  I don't think that's enough to show what I've been losing though?

I'm stumped.

Pics below are the tailgate.  You can see where I've wiped, and what is on the paper towel.  It doesn't appear to me to be enough for that level of oil consumption

One quart in 1000 might not be noticeable on the plugs.  I burn a quart every 400 or so and my plugs stay clean.

What rings did you use

Were the rings properly seated during break-in? (I'm abusing in break-in: hard on/off throttle progressively up to redline to load the rings).

What valve seals did you use, and did you install them correctly?

Does the catch can fill up?

I've found sometimes a different PCV valve is needed if you've changed the way an engine breathes. On my daily driver (11:1 SBC, ported heads, snotty cam, 8inHg idle) I went through quite a few PCV valves chasing oil consumption and ended up with one that has no valve in it at all, just a 1/32" orifice. Oil consumption dropped considerably.  I'll likely make one for MrsSkinny's oil-sucking VG30 as well.

1qt per 1000mi is still very "acceptable" by most car dealerships today.

I've heard (but never experienced it myself) that if you don't use break in oil after a rebuild by going straight to regular oil the engine will burn oil past the rings.

Usually can be fixed by running a few hundred miles on break in oil. 

Something about not really seating the rings until you use break in oil?

immediately popped into my head when I read the thread title. 

maybe your muffler is full of oil ;)

Forged or cast pistons?  If it's cast do the ring break in procedure like you mean it!   Hard accels!   If it's forged you can do it again, but it may always burn oil.  With forged pistons you typically get one shot at this before the cylinder walls are too smooth to seat the rings.  
 

What honing procedure was used?  This can also play a major role in ring break in.

Some of the questions asked are good ones. Without answers I'd say swap to break in oil, beat the snot out of it, maybe swap the pcv valve and really really investigate for oil leaks. On a newer engine with pretty clean oil, you may not get an obvious nasty black stain just a clearer wetness. Throw some baby powder at the block and make sure it's not leaking.

1000 miles to a quarter is acceptable for a newer engine with low tension rings and a manufacturer looking to reduce warranty costs but not on something like this

1 qt per 1000 still shocks me. My explorer decided the hood could be opened since I drove it for 5k miles because I needed it to do it.

1/4 quart low after I could finally get it open. Wife's golf? Burns about 10 times that

Piston rings: https://www.summitracing.com/parts/slp-e-229x
Pistons: https://www.summitracing.com/parts/slp-h519p
Valve seals were the Felpro umbrella seals that come with their top end rebuild kit.  Installed properly from what I could find in how-to stuff

I think I used regular oil with a break in additive?  I'll have to try and dig more into my email for orders.  I'll have to try and get ahold of the guy that did the machinework to see how they prepped the block

"Break it in like you're going to drive it" is what I've always heard, and I damn sure did.  Lots of hard accels and decels.

Definitely not weeping outside, I've checked multiple ways.

I've had the catch can on for about a week and a half, so 400-500 miles?  It doesn't look anywhere near filled though.  I think its about a quart size, but I'm not sure what sort of baffles are inside it.

A quart per thousand may be appropriate for a manufacturer, but it damn sure pisses me off, so I'd like to try and fix this.

I know it is a very very old trick to try, but has anyone ever known anyone to use borax/comet/bon-ami powder to seat rings?  Its supposed to be abrasive enough that it scratches the walls enough to give one last chance at setting the rings.

I have heard of folks just dumping a teaspoon of Borax into the carb just as you womp on the throttle.  Never done it myself. I've heard it works. I've also heard from a different source that that is what you do with Chrome rings. I can't substantiate anything.

I'm not convinced "Break-In Oil" makes things break in better. I believe it has additives to prevent the engine of wearing OUT during break-in. Additives that are not in regular oil so as not to pollute the cats.

Case in point: I've been running a container of Break-In Additive into my daily-driven flat-tappet cam 350 with every oil change since I built the engine in 2013. Every oil change. Four oil changes per year. Eight years. The engine is doing lovely.

And I'm ok with oil consumption that is a quart between oil changes, but not more than that.

SkinnyG (Forum Supporter) said:

1qt per 1000mi is still very "acceptable" by most car dealerships today.

That's a bunch of BS as far as I'm concerned (dealers saying it's ok because they don't want to fix the problem). I've never owned a car that burned anything close to that amount of oil. 

With the multitude of cars I've owned, from high mileage E30s, to a new Mustang or Frontier, I've never had a car that used more than a half quart between 5000 mile oil changes. 

In reply to z31maniac :

It isn't "the dealers", it is "the manufacturers".  Dealers will happily rering an engine but it won't be covered by warranty.

It is also somewhat flexible. If the engines are problem children the number gets lower.  IIRC the LS6 engines would not get covered under warranty until 1 quart in 200mi.

So I'm driving home from my sister's this weekend.  Fill the tank, take a leak, check the oil.

I notice this oil slick on the fender well.  I trace it back thinking its from an oil bottle I have stored underhood; it isn't, its from the fume/breather thing that goes to the intake before the air filter.  I look at the tube where it goes into the valve cover and I've got another oil slick.  There's been some oil leakage there before, but in the past I've chalked it up to the nozzle/nipple thingie popping out and it leaking.  Now I'm wondering if there's more going on there?
This is new to me installing the catch can.  Any possible thoughts going on here?

Your PCV system is plugged, so engine blowby is blowing out the breather going to the airbox, carrying oil with it.

Could be a stuck valve, could be plugged passages in the intake manifold or valve cover.  If it's a stuck valve I strongly suggest cleaning it with a can of carb cleaner, maybe two.  Replacement valves are often calibrated wrong and cause issues.

Pete. (l33t FS) said:

Your PCV system is plugged, so engine blowby is blowing out the breather going to the airbox, carrying oil with it.

 

Could be a stuck valve, could be plugged passages in the intake manifold or valve cover.  If it's a stuck valve I strongly suggest cleaning it with a can of carb cleaner, maybe two.  Replacement valves are often calibrated wrong and cause issues.

 

I think there's something weird going on under the valve cover, but I'm not sure what.  I plugged a vacuum gauge into the PCV tube/Catch-can system I have and got a decent enough vacuum signal considering the plastic line to the rubber line to the next rubber line.  The PCV valve is the correct Motorcraft part for the truck.

And for E36 M3s and giggles, the K&N filter and the inside of the air box.  The inside of the plastic tubes connecting the box to the throttle body is clean at least.

And changed the plugs.  None are pretty, but #5 is especially not pretty.

The oil is going out #5...

I'm sorry about this. But it's been fun watching you diagnose the issue. 

At this point you should put new plugs in and shoot some NOS to it.

How much depends on if you want to have parts to rebuild with or not, but a 125 shot may work.

5 doesnt look good but Ive seen plugs that looked worse that didnt consume this much. How old are those plugs?

That breather is just supposed to be a fresh air intake to replenish what the PCV system removes, seeing it spray out there and push a bunch of oil to the intake would generally make me think a bunch of blow by or as mentioned earlier PCV system not working. You have a good vacuum signal to the PCV valve but is the pcv valve actually opening and closing?

My ranch truck 4.9 hasnt had an actual oil change in a decade or so (it just gets a new filter spun on opening weekend and topped off occasionally), it leaks and it doesnt use this much oil.

That might have an oil ring expander overlapped.

Ask me how I know..

Sounds to me like you have a few choices at this point. 
 

1) Magic's fix (borax, restore, marvel mystery oil, etc) 

2) put a bore scope down #5 to check to see what's going on. 

3) pull the head and see what's going on. 

In reply to Fueled by Caffeine :

I've got the bore scope.  What am I looking for?  Check the intake side? Into the spark plug hole?