2007 Maxima engine, with the VQ30 timing/ecu conversion. Using the VQ35 oil pump.

Driving last night, started to make strange noises, most noticeable at light acceleration.

I noticed at idle, the "oil" light came on, but went off as soon as the revs came up.

Checked oil level, it was fine.

Let the car sit over night, and the noise seems to have gone away and the oil pressure is also OK.

Is this a oil pump failure warning? Maybe some check valve is stuck?

Thanks.

 

You can buy a mechanical oil pressure gauge from the auto parts store to check your oil pressure. Low oil pressure is not always the pump, however. Excessive bearing clearances will cause the pressure to be low as well. The problem could also only occur while the engine is warm due to metal expanding as it's temperature rises.

 

Drained the oil tonight.. Lots of small metal particles in it.

Dropped the oil pan, and found one of the thrust washers broken and laying in there.

Any ideas on what would cause this to fail?

Rock Auto has DNJ ENGINE COMPONENTS Part # TW632 listed.. $11.00. Anyone have experience with this brand? or a recommendation for a specific brand that may last longer?

Thanks

 

The OEM parts are 5 for the upper, and 10 for the low thrust washer. I would use those. You need an upper and lower for each side of the 3rd bearing cap. However, I don't think you can replace those without removing the 3rd bearing cap so this could turn into an engine rebuild.

But the real question is why did one of your thrust washers fail?

 

Yes, I saw the cost for the Nissan OEM parts too (Courtesy). I also see there are some other aftermarket. Cosworth and ACL. They any "better"? The marketing materials would indicate so.

Why would removing the 3rd bearing cap turn in to a full rebuild? Can you elaborate?

As for what damaged it, I have a few theories.. This engine is bolted up to a Porsche transmission that uses a "pull" style TOB for clutch engagement. I am thinking maybe it is maladjusted and I am pulling too much? Another thing I noticed after I changed the engine last year (and had the flywheel cut) is the new clutch has a lot of chatter when it engages, the cut may have been done wrong causing the chatter and maybe even slightly off balance. All things I need to check on.

 

If you loosen one bearing cap, you must loosen them all. At that point, you might as well redo the main and rod bearings, especially with all that metal in your oil.

 

Why do they all need to be loosened? is it to get access to something? or just to follow the torque procedure?

 

It's physically impossible to remove just the 3rd bearing cap because of the bearing cap beam. You have to remove the beam to remove the bearing cap, and you have to removed every bolt from every bearing cap to remove the beam. Even if the beam wasn't there, the FSM states there is a strict order in removing the bearing cap bolts, and you are supposed to loosen them in steps to avoid deforming anything.

If you did just want to do the thrust washers, I suppose you could remove the beam per the instructions in the FSM, and just remove the 3rd bearing cap. You have to remove the lower and upper oil pans to get the beam off. You'll have to remove the cross member to do this unless you pull the engine.

Since you have to remove all of the bearing caps anyway, I would just replace all of the main bearings as a preventative measure. To do this you'll have to remove the crankshaft, which means disconnecting the connecting rods, giving you access to the rod bearing while you are there. Howver, to remove the crankshaft, you'll have to pull the oil pump, which requires you to take off the outer timing cover and timing chains. You might as well replace the chain guides if you remove the timing chain...you can see how this could turn into an entire rebuild very easily.

 

I have been able to replace main bearings (in a ford engine) without removing the crank from the engine. They just rolled in and out. Why would the same process not work for the Nissan?

 

You can try, it's a pretty tight fit though. I don't really think you could roll out the bearings from the engine block journals. The standard main bearing clearance is 5-12 ten thousandths of an inch (0.0005-0.0012). When I rebuilt my bottom end, there was a very slight interference fit between the journals on the block and the bearings.

 

I have done this on a few different engines. The ONLY thing I could imagine hindering this method would be a dowel pin, like on air cooled VW. I have never been into the lower end of a VQ, But I would say try it.

BTW WTH do you have a VQ3.5/Porsche trans mounted in? If its a sand rail, pics are required as well as Youtube vids. Same rules apply for open wheel racer.

 

Never mind, did some searching. Awesome car.

http://www.deloreanmidatlantic.com/s.../levy/levy.htm

 

Those pics are from 2006.. that was my original 2003 engine. I installed the ProCharger C2 on it, and blew it up.. Swapped in the 2007 VQ35, and that is the one I am trying to fix now..

No idea how much HP is it now with the SC, but I was getting about 6LBS of boost.

There are some videos of the car moving on YouTube.. Some before the SC, some after.

 

Its doesn't looks like oil pump failure notice but might be there is some dust particles in the oil filter or in the carburetor, so its better to drained the oils.

 

Is there a guideline for proper oil pressure VS RPM?

I replaced all the bearings in this engine (see my other thread), and that fixed the noise. The trust bearings were smashed and destroyed, the rest of the bearings had lots of wear on them from (I assume) the lost oil pressure.

With the engine back together now, about 1000 miles on it, it seems to be running OK but I am concerned that the oil pressure is still too low. Once it is warmed up, I have maybe 10PSI at idle, and it hovers around 20PSI at 2K RPM. Is that normal?

Thanks