2004 350z replace rings or replace engine

Nissan 350z / Nissan 370z technical discussion forum: Maintenance, performance, installations, modifications, how-to's and troubleshooting.
Crow350z
Posts: 1
Joined: Mon Nov 16, 2020 4:13 pm
Car: 2004 Nissan 350Z

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2004 350z replace rings valve stem seals or buy used engine


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mrwrolguy
Posts: 81
Joined: Sun Nov 26, 2017 2:39 pm
Car: 2004 White 350z Touring Edition

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replace engine... you can get a JDM engine shipped from Japan 50k+ miles for 1500$ and remove the Cats and replace with resonated test pipes... the cat dust on decel getting pulled back into cyl destroyed your rings. I swapped my engine is a couple of weekends. Good Luck. ps mark everything and take pictures expec the coils and injector plugs if you swap engine harness.

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VStar650CL
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Joined: Thu Nov 12, 2020 1:25 pm
Car: 2013 Nissan Altima 2.5 SL
2004 Nissan Altima 2.5 S

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Good advice. We see "cat inhalation" all the time, and not just on Z's. Nissans all have exaggerated valve overlap to suck back a little exhaust and avoid the need for an EGR. Works great unless a cat goes bad, then it inhales metal. It isn't worth re-working them once the walls are scrubbed.

Emrys
Posts: 3
Joined: Mon May 10, 2021 4:49 am
Car: 2006 Nissan 350Z

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mrwrolguy wrote:
Sat Nov 21, 2020 8:32 pm
replace engine... you can get a JDM engine shipped from Japan 50k+ miles for 1500$ and remove the Cats and replace with resonated test pipes... the cat dust on decel getting pulled back into cyl destroyed your rings. I swapped my engine is a couple of weekends. Good Luck. ps mark everything and take pictures expec the coils and injector plugs if you swap engine harness.
Any suggestions on a good JDM engine importer?

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mrwrolguy
Posts: 81
Joined: Sun Nov 26, 2017 2:39 pm
Car: 2004 White 350z Touring Edition

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I found mine via craigslist... I was in Houston and was a short trip... most large cities have importers

2003PATHFINDER2022
Posts: 31
Joined: Sat Jan 08, 2022 5:45 pm
Car: 2003 Nissan Pathfinder 3.5
2006 Nissan 350Z

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Great! Cats that wear out will destroy my engine, like I haven't replaced enough parts at 70,000 miles of normal use! How does one know if the cats are breaking down, the exhaust diagnostic device here in C R is very sensitive to contaminants being put into the atmosphere, I wonder if this problem shows up thru a diagnostic check, if not than how can I know about this problem?

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VStar650CL
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Joined: Thu Nov 12, 2020 1:25 pm
Car: 2013 Nissan Altima 2.5 SL
2004 Nissan Altima 2.5 S

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You'll always get a P0420/P0430 when a cat is dying. That's your early warning system. Sometimes cats last years after they throw codes, sometimes they come apart quickly, but that's a crapshoot. Those codes will usually be the only warning you'll get. On the bright side, VQ's like your Z are the least susceptible engines in the Nissan line to inhalation. It can still happen, but it's much rarer than on QR's and VK's.

2003PATHFINDER2022
Posts: 31
Joined: Sat Jan 08, 2022 5:45 pm
Car: 2003 Nissan Pathfinder 3.5
2006 Nissan 350Z

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P0420/P0430 code to inform me of cat. breakdown, my tecks here say "don't count it" You won't know until you achieve max blowby of the scrubbed walls and worn rings=another shot jap engine. My air bag light has been blinking for 2 years, air bag sensor problem, bad air bag? NO just a defective expensive ignition switch clock spring! I put no trust in so called 'computer code diagnosis" what so ever. 9 out of 10 times a problem is never the big important part, it is nothing but another overly complex system of sensors, relays, sending units or a crap wiring job from the factory.

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VStar650CL
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Joined: Thu Nov 12, 2020 1:25 pm
Car: 2013 Nissan Altima 2.5 SL
2004 Nissan Altima 2.5 S

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P0420/P0430 with no other codes and no exhaust leaks are very reliable indicators of a dying cat. With other codes, particularly induction codes, it's a different story.

Driver airbag codes on any Nissan are always from the clockspring. The airbags themselves virtually never fail.

The moral of this story is, codes are only (ever) as useful as the person analyzing them.


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