Fully Rebuilt OEM 420a Engine Eats Oil

[DSMOCTANE]

-My father and I have just restored my 1999 Mitsubishi Eclipse GS with the naturally aspirated 420a engine. I have been experiencing rapid oil loss as well as some bluish smoke out the tailpipe. OBD-II is showing DTC P0300 misfire codes for all four cylinders and cylinders #3 and #4 are fouling plugs. Compression check shows a firm 190 pounds across all four cylinders on the fully rebuilt engine that now has 850 miles. I have replaced my crank/cam position sensors and had the PCM relearn the position of the crank and cams using the DRB-III Chrysler scan tool. I also have an MSD Blaster coil pack installed on the car, and even tried using the OEM coil pack to see if the misfires would go away. I lose a quart every week and have no idea where its all going. Is there a way to test the valve seals using a leak down test? Aside from the possibility of improperly installed valve seals in those two cylinders, what else could be the root cause of this rapid loss? The car never smokes at idle, but only between 2 and 3 1/2 thousand RPMS between gears while I accelerate. No puddles of any sort underneath the car either...

 

[bryanwheat]

Was the block properly honed? What was the measured piston to wall clearance? Did you properly install the oil control rings?

 

[DSMOCTANE]

Yes, the block and head have been pressure tested, decked, honed, and plained at a well trusted machine shop where we have had work done before. All rings were properly installed on new pistons and compression is a steady 190 pounds. I am wondering if my PVC pipe that goes from my crankcase to the intake manifold is possibly too restrictive. I hear people eliminate it entirely and put a nipple on the manifold nipple and put a little breather filter on the valve cover. Just trying to go through process of elimination.. WTF

 

[2ndgen420]

Head gasket? Maybe, is their oil on any of the plugs? In my opinion sounds like a head gasket problem.

The PVC wouldn't cause that big of an oil consumption problem oil is getting into the cumbustion chamber some how.

 

[DSMOCTANE]

Like I said before, the motor has solid compression in all 4 cylinders with 190 psi per each reading. Temperature of the car is smooth and the coolant has no contaminants whatsoever. Today, I had put a breather filter on my pcv pipe and put a rubber nipple to seal off the manifold. So far much less smoking and smoother idle. I hope this clears up my problem..

 

[bryanwheat]

Like I said before, the motor has solid compression in all 4 cylinders with 190 psi per each reading. Temperature of the car is smooth and the coolant has no contaminants whatsoever. Today, I had put a breather filter on my pcv pipe and put a rubber nipple to seal off the manifold. So far much less smoking and smoother idle. I hope this clears up my problem..

You can definitely have good compression with incorrectly installed or damaged oil control rings. You still never answered my question about the piston to cylinder clearance.

 

[92AWDHX40]

Did the machine ship assemble your engine or did you, and if you did, was everythi ng within spec and what,if anything was measured?

 

[DSMOCTANE]

-All machine work was handled at the machine shop while my father and I assembled the motor at home. When we put the pistons in my father had check the gap between the pistons and cylinder walls, and it was pretty close to what the bible called for. But off the top of our heads, we cannot recall that exact precise number of what it read back then. After chatting with a GSX owner this evening, I have begun to wonder if using 5w30 Mobil 1 in my rebuilt 420a motor for the break in period was a bad idea. I wonder if since machine work and honing has been done, if this weight may be too thin for the refurbished motor. Its about that time for another oil change anyway, so I may either running 10w30 Mobil 1 or even go with the Shell Rotella. WTF

 

[BoostedPhoenix]

-All machine work was handled at the machine shop while my father and I assembled the motor at home. When we put the pistons in my father had check the gap between the pistons and cylinder walls, and it was pretty close to what the bible called for. But off the top of our heads, we cannot recall that exact precise number of what it read back then. After chatting with a GSX owner this evening, I have begun to wonder if using 5w30 Mobil 1 in my rebuilt 420a motor for the break in period was a bad idea. I wonder if since machine work and honing has been done, if this weight may be too thin for the refurbished motor. Its about that time for another oil change anyway, so I may either running 10w30 Mobil 1 or even go with the Shell Rotella. WTF

You do not simply check your ring end gap, you set it by grinding the ends of the rings to fit the specified gap. 190psi is low for a 850 mile motor, Spec is 210psi so it sounds like either you did not get the rings seated properly or they were not correctly installed/gapped.

 

[DSMOCTANE]

The engine had shown 200 psi when we first got it in the car and ran it for the first few hundred miles. It has since went down to 190 psi and cylinders #3 and #4 continue to foul plugs. Cylinders #1 and #2 seem to be firing great with no issue whatsoever. I took off my intake today and found lots of oil inside of the throttle body butterfly and manifold. I tried running Shell Rotella 10w-30 instead of the 5w-30 for a change today and she still continues to smoke. Seems like oil is either somehow being sucked in through the intake mani or perhaps experiencing blow-by through just those two cylinders. Misfire codes still continue to appear for all cylinders as pending and the P0300 is throwing the CEL on. I hope I can get an extension on my emissions testing so I can reregister this damn car.

Rings were installed accordingly to the simple directional instructions and also as is as OEM rings. Block and head were tested and cylinders were properly honed. I am wondering if my valve seals have been incorrectly installed in those two cylinders. Why would rings not set in those two cylinders but in the first two and yet still continue to show steady compression in all four cylinders entirely?

 

[buhay6]

what I would do is find another motor that's running swap it in for now (to pass emissions) and tear down the one you have to find out what is/went wrong. Rather stop now than cause more damage if it is serious.....but that's just personal opinion.

In all honestly bryanwheat has helped me out by answering my dumb/noob questions and I always see him posting in other forums helping people out and he really knows his DSM's. So not trying to be a dick but if he says check your piston to cylinder clearances I'd do it..........he's been around the block once or twice from what I hear/seen.

 

[DSMOCTANE]

This already is my second motor. I'm just getting ready to give up on the 420a... mad:

 

[buhay6]

well you seem pretty mechanically inclined so why don't you just do a 4g63 swap?