Hello, I am new to the board and hoping for some help with my EJ25 rebuild. I have done a complete rebuild of the motor. History.... Crank, rods, block and heads were taken to machine shop, all checked out in spec, had heads redone with new guilds, seals, and valve job and surface. Installed new bearings throughout. Replaced one piston #3 with OEM, my fault, ruined on clean up. New DNJ rings all pistons, had to size each. OEM Gasket set including head gaskets. All went together fine, all clearances checked with mics and bore gauge. Installed engine, fired up no problems, ran good. After maybe 4-5 run cycles 10-15 minute trips to store it started smoking bad. Figured rings not seating so went on two 40 mile hwy runs both in excess of 1 1/2 quarts of oil, looked like a crop duster even at idle. Pulled plugs, #4 oil fouled bad, ran compression check #1=210, #2=210, #3=210, #4=225. Pulled PCV hose and did not see excessive case pressure, so I figured on oil ring or valve guide failure, no oil in water or vise versa so felt like head gasket ok. Pulled engine, disassembled, took out #4 piston which looked fine other than standing oil in the cylinder. Now thinking head failure, took head and piston back to machine shop, machine shop could not find anything wrong with head or piston.

 

So now I am looking for any help someone on the board may have. Could it have something to do with oil separator/ PVC, if so why #4? Intake gaskets were wet with oil both sides. Before I go back together should I re-ring it? What could I be missing? 

 

Thanks for any help you may have.   

so we have oil loss but no compression loss.  

 

it sounds like there's oil coming through the intake - can you verify and inspect that more closely ,try and follow a trail?

 

it's not the valve stem seals/guides?

 

what was the history of the motor before the rebuild?  

what was wrong with it and what the previous parts look like?

Thanks for the reply.

 

Car had 185k miles and had the normal head gasket problem, over heating leaks etc.. Bought it this way, DD will be 16 in a year, figured it would be fun to rebuild, work out all the bugs and give to her in a year or so.  

 

Yes compression was good. Head checked out good. Had a long conversation with the machine shop and I explained my ring end gap procedure and he was astonished at how oversized the rings were upon purchase. I had only pulled #4 piston at that time. Wish I had kept the box on the rings but they were marked STD and then a O.S. .050. rings overlapped in the cylinder bore by over a 1/6 of and inch by eyesight. not being very experienced I went ahead and gapped them, even the expander ring and oil upper and lower. Machine shop said he had never heard of doing that. Pulled the other three pistons and found much more tension on those three oil rings. Honestly not sure I should have had to do the sizing on the rings like I did, but expander ring not go in the bore without some sizing. I did this by bending the exp ring taps in a bit until I got to spec.

 

All the parts looked great, except for the piston I ruined and replace with OEM piston.

 

At this point I am going to re-ring the motor with some ordered from the machine shop.

 

Still would like your opinion though, and any points you may have on the build with your experience.

 

Thank you!

did you line up the oil ring end gaps by chance? Even still , that would be a ton!

No, 180 degree opposite, as shown in SM. Yea it was smoking so bad I could not believe it ran as good as it did.

triple check breather hose routing? triple check cam timing?

 

measure oil pressure?

 

does kinda seem like an intake valve problem - too tight? dropped guide?

 

 

just wild guessing

Did .you get the cylinders honed achieving a cross hatch pattern. to help rings seal.  otherwise cylinders / bores could be glazed.

 

Did you check / size each of the rings individually in its respective bores ( checking ring gap etc in at least 3 positions in bore using its piston to push in)

 

When  fitting rings to pistons did you position all ring gaps equi - distant from each other?

Edited January 7, 201610 yr by subnz

Was number 4 the only plug with oil fouling? Were the rest totally clean or just less fouled than number 4?

"Had a long conversation with the machine shop and I explained my ring end gap procedure and he was astonished at how oversized the rings were upon purchase. I had only pulled #4 piston at that time. Wish I had kept the box on the rings but they were marked STD and then a O.S. .050. rings overlapped in the cylinder bore by over a 1/6 of and inch by eyesight. not being very experienced I went ahead and gapped them, even the expander ring and oil upper and lower. Machine shop said he had never heard of doing that. Pulled the other three pistons and found much more tension on those three oil rings. Honestly not sure I should have had to do the sizing on the rings like I did, but expander ring not go in the bore without some sizing. I did this by bending the exp ring taps in a bit until I got to spec."

 

New standard rings and a hone job will probably fix this. First time I've ever heard of someone installing .050 over rings in a standard bore. At most a .010" over ring set can be filed and fitted to a standard bore. The OS rings filed that much exert a ton of pressure on the cylinder wall.

 

The oil in that cylinder is the reason for the higher cranking compression. The ring mfg has a preferred cylinder wall finish. You didn't say what grit you used on the hone job.

Yes, thank y'all for the replies. I agree that the ring set I received was likely not correct and I should have known better. The machine shop did the hone job and did just enough to remove the glaze. not sure of grit. I will ask, was not going to re-hone for sake of not splitting the case, or removing any more material.... do you think it is necessary? I can see cross hatch and  I can also see some mirrored looking areas where the piston skirts run but can still see some cross hatch in those areas as well, just not as much. Getting new rings this evening. 

Sorry, forgot to answer the cylinder question. #4 was by far the worst. The others had some carbon build up as well.

Ok, think I found it. The expander part of the oil ring where the gap is has little tabs that but together with a wire going thru it. This is where I used some pliers to squeeze them in a bit to set clearance. One side of the tab broke off in #4 and caused the oil ring in that cylinder to lose retention. Next time I will not use rings that are oversized for a standard bore. I lived an learned on this one. 

 

Checking back on my order, I ordered the rings from Parts Geek assuming at the time they were standard, they were DNJ part number DJPR715, no where on the online ring description does it show that they are oversized. Should have sent these back and just used my Machine shop to order the rings in for me. This is what I wound up doing this go around, using Hastings rings standard size I did not have to size even one ring. Put them in the bore checked end gap they were all good out of the box.

 

Special thanks to Ed Sr. and Ed Jr. at Arlington Automotive Machine for taking the time to spend with me analyzing and correcting my screw up.

 

Also Thanks to those of you on USMB for giving me your thoughts.

 

Guess I will let y'all know if it last more than 200 miles this time

Only other reason I would think of for excessive oil in one cylinder is a damaged valve stem seal.

You're gonna see oil in the intake manifold because of the way the PCV system works.

 

When you installed the pan did you make sure to put the funny square o-ring on the tube in the back corner? Using the wrong O-ring or no o-ring there will lead to excessive oil consumption but it's generally more like 1 quart in a thousand miles.

 

Wrong rings sounds like your culprit though. For future reference, NPR (Nippon Piston Ring) makes the factory stuff for Subaru. DNJ may be fine but IMO if you're that far into the engine there's no reason to buy inexpensive rings just to save $20.

 

Good luck!

Hello Sooberoo, Yes I used a full factory gasket set and did replace the O-ring on the tube in oil pan. Fairly sure the broken expander ring is the problem. Honestly I wasn't trying to save any money on the rings other than not paying $165 for factory, even when I shopped factory rings online they only offered oversized. As I stated I replaced the rings with Hastings this time around and they fit great. Thanks for the info on NPR though, next time I will give the a try.