Please tell me its not rod knock

[SpecVrooom]

2002 Nissan Sentra SER-Spec V (engine QR25DE) approx. 110K milesNo mods

Checked: Spark Plugs/Injectors - no visible damage or abnormal wear.

This just started happening about a week ago, its driving me nuts. Sometimes I think its under the valve cover, other times lower. I try to listen with a stethescope, but all the metal seems to transmit the sound.

The sound occurs a little between 2200-2400 RPM in neutral. It always happens under load, doesnt happen on de-acceleration, doesnt happen when at idle. It seems to dull during other RPM ranges and not in others, making me think a simple vibration, but since I can hear it through the block, I unfortunately ruled that one out.

Was thinking rod knock, or piston chatter. However since this is something that is learned through experience and this being my first encounter with the problem, I cannot tell if the sound is either of those or something else (crossing my fingers).

I did just get this back from the dealership about 2-3 weeks ago too. There were several recalls they did on it.

1) RECALL R3136 ECM FOAM2)RECALL R0712 ECM REPROGRAM3)RECALL R0316 SENTRA ENG EX NTB07-081 CAMPAIGN4)RECALL R0316 SENTRA ENG EX BT030-070 COVER-EXAUST5) NISSAN RECALL R3022 CRANK POS SENSOR NTB03-124

I was thinking maybe that pre-cat/butterfly screw problem...?

I am in a bit of a crunch to figure this out, so any help would be greatly appreciated.

Thanks

Modified by SpecVrooom at 11:50 PM 5/15/2008

update: checked the butterfuly valves, they are fine, broke a long screw somehow when torquing, before the torque was reached, and the others torqued just fine, so, all around, not a good night. Hellp!



Modified by SpecVrooom at 3:47 PM 5/17/2008

Modified by SpecVrooom at 8:37 AM 5/22/2008
Modified by SpecVrooom at 8:37 AM 5/22/2008

[MaximA32]

Any chance you could get a clip of what it sounds like?

[SpecVrooom]

thanks for the reply, but got it figured out...was the timing chain guides, one is busted i believe, havent cracked into it yet, but have 2 mechanics that confirmed it.

[SpecVrooom]

Okay, I lied, and so did the other two mechanics (not holding it against them). After taking off the oil pan, there was my problem. A thrust bearing. Great! So I have been pouring over the FSM to see what it is going to take to do this, and Holy S*&!. Easiest thing to do it pull the engine to get to everything you need. Problem is I am an average joe, I don't have a puller and just a floor jack. I talked to 1 mechanic and he said I could do it from the bottom. My question(s) is...Can I take off the lower cylinder block to get to drop the crank without taking out the connecting rod assemblies and having to take off the top of the engine and "push" them through the top like the FSM says? Whats the chances of changing just the thrust bearing without taking out the crank? Just taking the lower block off?

[nismoracingsx]

you don't actually remove the block if you leaving the engine in. pan gets dropped, pump, and crank gets dropped from underneath, thats where the thrust bearing will be.