dbsoccer

Thanks Moses, Yes this is a mystery. I did learn also the guides where either to spec or they were replaced when I had the head reconditioned. I believe they replaced all the exhaust guides and left the intakes alone because they were to spec. I installed the seals. I recall they snap into place but I can check them without pulling the motor. It's not easy but it is much easier than a motor pull. I still feel the issue has something to do with the crankcase/PCV/EVP/etc. I have a new PCV valve to install but not sure the current one is defective. Both are OEM. But one thing that bothers me is when I go to check the oil the dip stick has 'popped out'. By this I mean, the top of the dip stick has a rubber gromment of sorts that goes into the dipstick tube. It has an interference fit so you need to push it to get it to be fully seated. The rubber holds it as well as seals the crank case at this point. But each time I go to check the oil after it has been driven for any period of time, the stick is no fully seated. Hmmmm? I need to measure but I would assume the bottom of the tube is below the oil level when engine is off. But when it is running I would expect, at least momentarily, the bottom of the tube is uncovered. The oil level drops because oil is pulled up into the motor etc. But....... in either case, the crankcase should be under a slight vacuum and not have a positive pressure. That is if the PCV system is working as intended. With the engine running I measure a vacuum at the engine side of the PCV of roughly 15 inches of Hg (I'm at 5000 feet). The dip stick tube has neither any pressure or vacuum at idle. I need to check at higher RPMs. I would expect to see a vacuum. If there is a vacuum or nothing, the dip stick should stay in place. Not sure what but the stick may becoming unseated for some other valid reason. My wife just told me the previous owner of the car said it consumed oil as well. Your comment about deflector or baffle missing is interesting. If oil was not returning to the pan quickly enough and preventing the vacuum from the PVC system from reaching the crank case pressure may build up. If the cam clearances were too large it may cause an undo amount of oil to be in the valve cover again, flooding the oil return passages so the PVC system wouldn't work. Again, pressure in the crank case and maybe oil is being pulled into the PVC valve. Just speculating here as this doesn't seem to be a classic case of a oil consumer. I'll continue with my investigation and keep you in the loop. Thanks again.

Hello Moses, I completed my compression checks and leakdown. I used a Snap On compression tester and two different leak down testers. I built a leakdown and used an OTC to validate the readings of my homemade set-up. It turns out the readings of both leakdown tester matched well within the accuracy of the gauges used (+/-3-2-3, typically) so I'm happy with my home made tool! Compression was 175psi+ on all four cylinders. They were all within a couple of pounds of each other. The leakdown readings ranged from 4% to 7%. To me this means the motor is tight. Just driving it I can tell it has some pretty good pep for a 2L stock engine. The Rav4 is a heavy car for its size and it accelerates pretty nicely. With regard to the PVC, I crimped the line between the PVC valve and where it ties into the intake manifold. As expected the rpm dropped 50 or so. My understanding to date, is this simple test will verify a work PVC system. I have not concluded that yet, however. There may be other things to check in this system. Any ideas? Thanks. Brent

Hello Moses, Great questions. I'll answer them but first I did complete the oil pressure test yesterday. Idle (~900rpm still a bit cold from start up) the pressure was 32 psi. At ~3000 rpm the pressure approached 70psi. So my fear of loose mains is minimized. I used a new Toyota pump so the numbers are where I'd hoped they'd be. I plan to go through the PCV system with a fine tooth comb. One line was new and the valve was new (OEM). I don't feel I have a timing belt noise. I did initially as I assumed the tensioner spring would provide the load I needed but I learned new belts relax a bit so I pulled the engine back down and re-did the tension using a new spring and then "going a bit tighter" as advised by some friends in the business. The belt and idlers were new during the rebuild as was the oil and water pumps. The motor had 240k miles on it prior to the rebuild. I worked with a quality machine shop in town for my block prep, crankshaft work and cylinder head work. The bores were fine - size-wise and taper so the shop just honed them to "break the glaze". I'm not sure of the exact honing process but I'm confident the didn't use a tool you can buy off the rack at your local NAPA parts store. These guys are known for their quality. Stock pistons and standard rings. I did check ring gaps during assembly. The crank dimensions were fine so I used standard bearings for both the mains and rod. I used pasti-gauge to verify my bearing clearances. The shop polished the bearing surfaces. I took time to make sure the crank's oil passages were clean using brushes, etc. I used the original pump screen but it was very clean as well. I did wipe down the cylinder walls with ATF as a final cleaning prior to installing the pistions. All of my parts came from Federal Mogul or one of their companies like Sealed Power, etc. I bought a Re-Ring kit from Summit Racing. The kit included the rings, bearings, gasket set and valve seals all from FM. I figure the leakdown will help me eliminate questions about bore prep and ring seating, etc. While I don't think the leak down is intended to test the function of the oil rings one could assume (as risky as that is) if the compression rings are sealing (which is tested via the leak down) the oil rings are probably happy as well. I.E. the honing and sizing, etc provided for proper ring seating. But until I get the test done I'm still just guessing. The oil pressure test was good news. What is odd is the tail pipe is not what I'd call black from oil burning. I've seen a good number of vehicles that burn oil and their exhaust pipes are typically coated with oil and/or black soot such that your finger would be a nasty black if you wiped the inside. While this car's pipe has a black coating it isn't what I'd call excessive. And there are no apparent leaks. Anyway, I'll keep plugging away. Thanks for your help and insight. Brent

Don't know if the 4WD Rav4 fits here but I figured I'd try anyway. My question is pretty generic so others may benefit as well. I recently (10k miles ago) rebuilt the engine in my Rav4 and it burns oil. The rebuild was complete - new pumps, belts, idlers, bearings, rings, valve job, valve seals, etc, etc. I primed the oil pump before I started the motor and my gauge read 75psi or so which is what I'd expect from a new OEM pump. I have no noticeable smoke from the tail pipe or leaks on the floor yet I consume a quart in 1000 miles plus or minus. One thing to note is after extended sitting the engine rattles for a few seconds on start up, like a knocking rod, but then quiets down and sounds fine. The rattle on start up sounds like loose main bearings to me yet when assembled the clearances were fine. I plan to do a compression test, oil pressure test and leak down test. The oil pressure check is to check the mains. I'm not sure if the leak down test will tell me anything about oil rings function so I will ask. I figured loose mains may increase windage which could lead to increase oil burning. I am hoping someone may have some other areas to check that would lead to fixes easier than pulling the engine back out and replacing main bearings. Thank you in advance.