you should be fine on the engine.... as long as you get 03-05 you should be ok.

From 03 through 05 they were non rev-ups. In the later part of 05 they put out the rev-up engines but for MT only..

as far as the price, that sounds "ok".. other's may be able to chime in. But from that link above with the car parts.. my search showed me about that price range for used engines..

 

Do you just have the tapping sound and everything else is OK (drives fine, oil pressure fine...)?

Is the tapping sound irregular (sometimes almost gone, sometimes pretty loud) and arhythmic?

If yes maybe it is nothing serious.
But I don't want to give you false hope, especially when you sound a lot more like an expert than I am, and you probably know how a V6 running on 5 cylinders is supposed to sound (I don't)

FYI:
There is another thread about engine knocking sound with attached audio file.
By now it is sometimes (NOT always!!) so loud that the engine with closed hood sounds almost like a tractor . And to me it sounds similar to your description of something knocking inside the engine as if it were lose or hitting something.
But the frequency is not constant, it knocks irregular, sometimes it skips out, and oil is fine and engine runs totally fine too (no stalling).
The dealer said that it could be the fuel dampers. He said that if the sound is "arhythmic" it is most likely not a serious engine problem, and that it can still be the fuel dampers if the knock frequency increases with RPMs because the fuel pressure increases. After they came up with this diagnose, they looked at the TSBs and found the fuel damper TSB.
However the part is not in yet, so I don't know yet whether it will fix my problem.

 

The sound is very rhythmic. Its not an extremely loud tapping but its definitely noticeable. The car runs pretty rough however oil pressure seemed fine for the 10 seconds I let it run.

 

i have an o3 enthusiest 6 speed with a air intake and exhaust still has cats and everything. i chnaged the oil and used royoal purple my cars got 51000 miles on it i was getting on the interstate and it died. i pulled to the side of the road and it started smoking i looked under it and oil was leaking everywhere so i had it towed to my house and took the splash cover off and theres a hole in the block. i went from 3rd gear to 4th shifting at 5800 rpms car never mad any tapping noises or any signs of it going. had the right amount of oil its been sitting at nissan for 3 weeks now a piston exploded supposibly and there waiting on a answer on the warrenty if it'll cover it. thats gotta be a manufacturers defect i have nothing that would really cause it to blow the fluids where right the oil pressure was right clueless anybody had this problem?

 

Does the knocking get louder with an increase in RPMs? The easiest way to diagnose this is to just pull off the pan and check some of the rod bearings. You'll have to pull the caps off though as they may not "wiggle" even if they are knocking. If you have a stethoscope you could put it on the block and try see which cylinder it's coming from too which would also make the diagnosis easier.

 

The knocking doesn't get louder, it just gets faster.

My plan of attack is:

-Drain the oil and look for metal shavings
-If there are shavings, I'll just buy a used longblock
-If there are no shavings I'll pull the pan and look for "wiggle"
-If there's wiggle, I'll just put the pan back on and buy a used longblock
-If there's no wiggle, I'll start tearing down the motor from the top down.

Is it possible to remove the heads with the motor still in the car? There is a possibility that I bent a valve in which case I can pull the heads, ensure that the pistons were not damaged and just have the heads rebuilt or buy used heads.

 

+1111111

 

Bring me the car, we will do a budget build, and reinstall and tune with a good fuel system, youll be fine..

 

Most likely you will find a piston with a side of it missing above the dingland..The prochargers are NOTORIOUS for melting pistons...Dont really think there was enough TQ to bend a rod, but you never know..

 

What is the breakdown of what you'd do?

-Pull motor
-Tear down to locate problem
-Rebuild whatever's necessary
-Throw it back together
-Add a better fuel management system
-Tune it

Whats a ballpark estimate for the work, not including the $900 for the utec.

 

If they melt pistons at my boost level then the intercooler must be pretty crappy to not handle 7psi.

I think I'm going to invest in a snow performance water/meth inj. kit

 

*Usually* when a rod bearing is on it's way out, the knocking will get louder with rpms (and faster too). I find it hard to believe that you all of a sudden smoked a bearing though, it should be more of a gradual process that you'd start noticing ever so slightly and it would progressively get worse. I think your problem is somewhere else. If you bent a valve, a compression check would tell you that, which would be a hell of alot easier than pulling the heads. Just my $.02

 

you can get utec for cheaper than that.

 

The compression check was part of the plan before tearing into the top end.

Draining the oil and that whole spiel was to check out the bottom end.

 

I just talked to someone today who has an 06 motor for sale with low miles for $1500. If your interested, I can find out more for you?

 

I don't think the 06 will work, isn't that the rev-up motor?

 

06 6MT is rev-up
06 5AT is non-rev.

 

Thanks for the offer on the 06 motor, however as stated before, its a slightly different motor which would require me to get an 06 ECU and harness for it to work.

I've found that the 06 motors sell for quite a bit less than the 03-05 motors most likely because people are aware of the oil burning issue.

 

Update 5/11/07:

I did a compression test on the motor:

cylinders 1-5 =185psi
cylinder 6 = 145psi

Also the spark plug for cylinder 6 had its side electrode smashed onto the end electrode, so it basically had 0 gap. This is why the car sounded like it was running on 5 cylinders. I started it again after gapping the plug back to .030 and it sounds much better but the tapping is still there which makes me feel like I at least bent a valve or two.



I'll get up actual pics of the plug tomorrow but so far the damage is looking like:

1-4 bent valves
1 spark plug
1 piston + piston rings for cylinder 6
1 possibly bent rod

Oil pressure was perfectly fine upon cold start up, it was 30psi+ for the 3 seconds that I let it run.

So does anyone have any ideas as to what could have happened?