99 2.5 Heavy Oil Consumption After Rebuild

[GrayBastard]

Finished (or so i thought) rebuilding my 2.5l 4 banger about 6 months months ago, my first ever rebuild with almost no experience. But due to other issues i had not driven it ever since rebuilding it.

Over the weekend I drove it just under the first 200 miles and everything was running great, checked the oil after the first 50 miles and it was in range. When I drove it to work this morning the oil pressure gauge was acting funny (going to near zero when idling and only 20psi when driving). Initially I thought it was just the new cheapo pressure sender i put in failing already but then I checked the oil and sure enough it was bone dry, barely a drop showing on the dipstick. Immediately stopped driving and picked up some more oil. Adding oil fixed the pressure gauge and is now operating normally.

-There are no signs of a leak, especially not one significant enough to leak 3-4 quarts in 2 days.
-Have not been able to check the plugs yet, will do so after work.
-Smells a little bit rich
-Very heavy a black soot in and around the edge of the tailpipe, but have not observed any smoke at any point over the weekend.
- Engine code p1495 (leak detection pump), though I believe this is unrelated and have spent hours hunting this on its own.
-I didn't put it through any kind of break in because i wasn't aware that i should have done that. Im doubtful that would cause so much consumption though.

So in summary, it managed to burn about 3-4 quarts in about 200 miles of driving. Where do I go from here? What are the first things I should check? Thanks in advance

 

[Obi-Wan]

Improper piston ring stagger, oil wiper/scraper ring and old / damaged valve stem seals are really the only things that will cause an engine to consume that much oil so quickly.

 

[BlueC]

-I didn't put it through any kind of break in because i wasn't aware that i should have done that. Im doubtful that would cause so much consumption though.

At minimum, after a rebuild, the rings have to be seated via break-in. During this period, it's common to have some oil consumption. Proper seating of the rings involve light driving (and minimal idling) for the first 500 mile with the proper oil, then change and drive normal. If you were running it hard during this period, then more oil consumption is likely.

I'm not familiar with the 2.5, but quick search looks like that is a flat tappet engine which absolutely has to be broken in, and with the right oils. Otherwise, you're most likely going to wipe the cam. You've driven it this much, if it's going to happen, it has already happened or is happening.

 

[Juggernaut]

To add to the above, I wouldn’t get too excited until your certain the rings have seated. You could leaked down test just to gain some understanding of what’s going internally.

There’s different philosophies regarding break-in. I’m in the break ‘em in the way you want to drive ‘em camp. Warm it up and ring it out. The idea is higher pressures, better sealing, faster bedding, blah blah blah. It’s always worked well for me.

 

[Obi-Wan]

quick search looks like that is a flat tappet engine which absolutely has to be broken in, and with the right oils. Otherwise, you're most likely going to wipe the cam.

Yes yes yes.

Any flat tappet cam I've ever installed required that the cam has proper break-in lube and engine oil galleys pre-primed, then set the timing as close as possible to avoid as much cranking as possible, then run the engine no load at hi idle (1500-2000rpm) for about 15-20 minutes.

Never had an issue with this method.

 

[Juggernaut]

Yes yes yes.

Any flat tappet cam I've ever installed required that the cam has proper break-in lube and engine oil galleys pre-primed, then set the timing as close as possible to avoid as much cranking as possible, then run the engine no load at hi idle (1500-2000rpm) for about 15-20 minutes.

Never had an issue with this method.

This is absolutely correct for a flat tappet cam. Starting it up quick and quickly bring it to mid rpm, no load for 20-30min is the way to do it. Piston rings however do need load. The ring tension itself isn’t enough to establish a proper ring seal. Cylinder pressure and heat helps drives the rings into the cylinder walls, creating a better seal. Peak cylinder pressure is around peak torque, (so roughly 3200rpm). Gentle break in with too low load/rpm can unfortunately lead to cylinder glaze and excess oil consumption.

 

[pagrey]

It's pretty common to have trouble seating rings on a rebuild if you don't break them in correctly like @Juggernaut suggested or pick the correct type of ring for how you prepared the cylinder walls. Some fancy rings are a headache to seat while simple cheap cast rings normally are easy. Keep a really close eye on your oil level and read up about what driving conditions help seat rings. Whatever you do, don't switch to synthetic oil. It should work itself out unless something is messed up but this isn't that unusual to hear, at least for me.