370z engine blown

Zenki370 · 05-25-2012, 04:16 PM

Quote:

Originally Posted by gsxr750

Most likely the ring damage was caused by the rings never really seating properly or a excessivly lean air fuel mixture and even engine timing could do it or bad engine mapping

Exactly what i was thinking. Ive found with most brands, its better to just modify the catback if youre going to touch the exhaust and leave it alone there after. Its the one and only mod Ive done on my Z and it will remain that way until the warranty runs out. I dont have extra cash to replace the engine nor the legal help it would take to fight a warranty denial.

Fabsnoop · 05-25-2012, 04:54 PM

Just went to the dealership to take a look at the broken HFC. The whole entire honey comb of the cat was broken off. It was just moving around freely. The tech at Nissan said "the only reason Nissan decided to replace the motor is because this motor is known for having oil consumption issues." I asked him if he was certain that the cat was the reason the engine failed..He said "it's one of the reasons.." I swear they'll never give you a for sure answer to anything. Should i go the test pipe route, have the hfc replaced (probably the worst idea since permanent viagra), or put the stock cats back on?

Red__Zed · 05-25-2012, 04:44 PM

Quote:

Originally Posted by gsxr750

B.S. ! There is no possible way parts from the exhaust can be sucked into the engine thru the exhaust ports.

The engine is a simple pump and the exhaust can only pump pressure out, it can't work as a vacuum and suck particles back into it.

Dirt or foreign objects can only enter thru the intake or other sources, oil, broken internal parts, broken head gasket etc.

Back pressure is only a term used to describe the amount of restriction to exhaust flow caused by a internal muffler, baffle or cat etc. Back pressure does not mean a reverse flow of exhaust gases.

This guys example is a good reason to show why is better to keep the car stock, dealers and manufactures are always looking for reasons to deny a waranty claim if possible.

Just be glad they covered your repair under waranty.

Most likely the ring damage was caused by the rings never really seating properly or a excessivly lean air fuel mixture and even engine timing could do it or bad engine mapping

You know the exhaust ports stay open during the intake stroke, right? This is not a terribly uncommon occurrence (when cats go bad, that is)

gsxr750 · 05-25-2012, 11:13 PM

Quote:

Originally Posted by Red__Zed

You know the exhaust ports stay open during the intake stroke, right? This is not a terribly uncommon occurrence (when cats go bad, that is)

exhaust valves are only open after the mixture has been ignited and the gases expelled out the exhaust after combustion, no air is ever sucked into the exhaust ports.

Vacuum is only created in the intake port , not the exhaust port

Red__Zed · 05-25-2012, 04:45 PM

Quote:

Originally Posted by red6spd

Does anyone else find it strange that Nissan apparently found that the aftermarket cats where the reason a several thousand dollar engine went boom and they are still gonna eat all that money?????????????? Something does not add up here, seems like the OP's mod according to Nissan directly resulted in the warranty issue.

Dealer can expense it back to Nissan, Nissan knows OC is an issue and doesn't ask questions.

Dealer wins loyalty at nissan's expense. A single engine cost is trivial to Nissan. Pretty straightforward.

UNKNOWN_370 · 05-25-2012, 04:55 PM

Quote:

Originally Posted by Red__Zed

Dealer can expense it back to Nissan, Nissan knows OC is an issue and doesn't ask questions.

Dealer wins loyalty at nissan's expense. A single engine cost is trivial to Nissan. Pretty straightforward.

Yezzzirrr. That's basically what I was saying earlier. Why lose a customer over a $9000 engine if he may buy a $40000+ car every 3 years or so?

Jordo! · 05-25-2012, 05:07 PM

It's not impossible that this happened, but the major damage was almost certainly due to inadequate lubing due to oil consumption.

To be fair, it can be difficult to figure out what caused what when two more more mechanical components fail at the same time -- all that matters is that they are covering it.

I'd look into a different set of HFC's or TP's.

G37Sam · 05-29-2012, 02:16 AM

Isn't a little bit of exhaust sucked back in as some sort of EGR? I read somewhere Nissan uses that technology but not very sure

Shamu · 05-29-2012, 07:50 AM

Nissan dealers have been known to hire people. People post things on the Internet. People are highly unreliable.

Would love to see picture of said Berk cat. Evidence that cat material was found in combustion chamber or oil pan. Maintenance records of said 370z with accounting of people who did the work. Frequency and type of oil used. What kind of oil filters used for all oil changes. Any monkeying around with tune?

Yes some other motors have had issues with precats but haven't seen much evidence to regular cats located a ways down the system causing this on a VQ37. Not saying it can't happen but would like to see real evidence.

Otherwise this is just a bunch of pointless yapping and sensless product bashing.

Guard Dad · 05-29-2012, 04:38 PM

One vote for stock cats and peace of mind.

gomer_110 · 05-29-2012, 04:50 PM

Just get LTH's and then you can't have a problem with the cats. That's got my vote.

2011 Nismo#91 · 05-30-2012, 07:39 AM

I know this can and has been an issue for pre-cats. How ever this is just impossible for a normal Cat. Yes there is some gas sucked back during overlap but you have 5 other cylinders one of which will be exhausting completely. So at most the exhaust pressure would be reduced but as for an over all back flow of the exhaust is just BS.

Your blown engine was due to other issues, the destroyed cat is unrelated. And more then likely all the oil burning clogged the cat up and exhaust pressure just ripped through the clog. But all this is difficult to prove hence why they are just replacing the engine.

Red__Zed · 05-30-2012, 09:23 AM

Quote:

Originally Posted by 2011 Nismo#91

I know this can and has been an issue for pre-cats. How ever this is just impossible for a normal Cat. Yes there is some gas sucked back during overlap but you have 5 other cylinders one of which will be exhausting completely. So at most the exhaust pressure would be reduced but as for an over all back flow of the exhaust is just BS.

Your blown engine was due to other issues, the destroyed cat is unrelated. And more then likely all the oil burning clogged the cat up and exhaust pressure just ripped through the clog. But all this is difficult to prove hence why they are just replacing the engine.

Isn't piping separate to the cat, with each cat seeing three cylinders?

vjarnot · 05-31-2012, 08:07 AM

Quote:

Originally Posted by 2011 Nismo#91

Your blown engine was due to other issues, the destroyed cat is unrelated. And more then likely all the oil burning clogged the cat up and exhaust pressure just ripped through the clog.

This is the only scenario which makes any damn sense at all.

christian370z · 06-02-2012, 11:29 PM

Unless you go with test pipes, there are examples of all types and brands of catalytic converters failing, stock or not. In my opinion, the vast majority (myself included) have had nothing but great experiences with Berk HFCs.

05-25-2012, 05:07 PM	#7 (permalink)
Jordo! A True Z Fanatic Join Date: May 2010 Location: nirvana Posts: 6,394 Drives: 2023 NATM Rep Power: 419	It's not impossible that this happened, but the major damage was almost certainly due to inadequate lubing due to oil consumption. To be fair, it can be difficult to figure out what caused what when two more more mechanical components fail at the same time -- all that matters is that they are covering it. I'd look into a different set of HFC's or TP's. __________________ Enjoy it. Destroy it.

05-29-2012, 02:16 AM	#8 (permalink)
G37Sam A True Z Fanatic Join Date: Dec 2008 Location: Dubai, UAE Posts: 1,507 Drives: RB'd G37 Rep Power: 22	Isn't a little bit of exhaust sucked back in as some sort of EGR? I read somewhere Nissan uses that technology but not very sure __________________ '14 Viper GTS '08 RB'd G37S - Sold

05-29-2012, 07:50 AM	#9 (permalink)
Shamu A True Z Fanatic Join Date: Jan 2011 Location: Nor Cal Posts: 1,059 Drives: 370Z Racecar Rep Power: 21	Nissan dealers have been known to hire people. People post things on the Internet. People are highly unreliable. Would love to see picture of said Berk cat. Evidence that cat material was found in combustion chamber or oil pan. Maintenance records of said 370z with accounting of people who did the work. Frequency and type of oil used. What kind of oil filters used for all oil changes. Any monkeying around with tune? Yes some other motors have had issues with precats but haven't seen much evidence to regular cats located a ways down the system causing this on a VQ37. Not saying it can't happen but would like to see real evidence. Otherwise this is just a bunch of pointless yapping and sensless product bashing. __________________ Grant Last edited by Shamu; 05-29-2012 at 08:15 AM.

05-29-2012, 04:38 PM	#10 (permalink)
Guard Dad Enthusiast Member Join Date: Aug 2010 Location: South Orange County, CA Posts: 422 Drives: 2010 370Z Silver A7 Rep Power: 16	One vote for stock cats and peace of mind. __________________ 2010 Brilliant Silver, Base w/Sport Package, AT7, Katzkin leather, upgraded audio and lots of Dynamat and a bunch of small stuff.

05-29-2012, 04:50 PM	#11 (permalink)
gomer_110 A True Z Fanatic Join Date: Aug 2011 Location: Perrysburg, OH Posts: 17,992 Drives: '11 Nismo #528 GM Rep Power: 36942	Just get LTH's and then you can't have a problem with the cats. That's got my vote. __________________ '11 370Z Nismo #528 Fast Intentions \| Stillen \| Motordyne \| Uprev \| CSF \| Zspeed \| Z1 Motorsports \| AST \| Swift \| SPC \| SPL \| Whiteline \| Hotchkis \| Bride \| Schroth \| Robispec \| Cusco \| Nismo \| Volk \| Forgestar \| Hoosier \| RJM '17 Titan Bone Stock

05-25-2012, 04:54 PM	#2 (permalink)
Fabsnoop Base Member Join Date: Aug 2010 Location: Los Angeles Posts: 34 Drives: Nissan 370z Rep Power: 16	Just went to the dealership to take a look at the broken HFC. The whole entire honey comb of the cat was broken off. It was just moving around freely. The tech at Nissan said "the only reason Nissan decided to replace the motor is because this motor is known for having oil consumption issues." I asked him if he was certain that the cat was the reason the engine failed..He said "it's one of the reasons.." I swear they'll never give you a for sure answer to anything. Should i go the test pipe route, have the hfc replaced (probably the worst idea since permanent viagra), or put the stock cats back on?

05-30-2012, 07:39 AM	#12 (permalink)
2011 Nismo#91 A True Z Fanatic Join Date: Mar 2011 Location: NJ Posts: 2,413 Drives: slowly Rep Power: 40571	I know this can and has been an issue for pre-cats. How ever this is just impossible for a normal Cat. Yes there is some gas sucked back during overlap but you have 5 other cylinders one of which will be exhausting completely. So at most the exhaust pressure would be reduced but as for an over all back flow of the exhaust is just BS. Your blown engine was due to other issues, the destroyed cat is unrelated. And more then likely all the oil burning clogged the cat up and exhaust pressure just ripped through the clog. But all this is difficult to prove hence why they are just replacing the engine.

06-02-2012, 11:29 PM	#15 (permalink)
christian370z A True Z Fanatic Join Date: Jul 2010 Location: Newport Beach Posts: 3,900 Drives: 2010 370Z/Saab 900se Rep Power: 433	Unless you go with test pipes, there are examples of all types and brands of catalytic converters failing, stock or not. In my opinion, the vast majority (myself included) have had nothing but great experiences with Berk HFCs. __________________ -320whp / 259wftlbs- SP Rays -- RE-11s -- SpecialtyZ Tune -- Swift Springs -- Stillen 25R Oil Cooler -- Stillen G3 Intakes -- Berk HFCs -- F.I. 12" CBE -- Stillen Sway Bars -- Es14 Spring -- INGS+1 lip -- CF Spoiler -- GTR Start Button -- VLED Parking Lights -- PWJDM V2 shift knob

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