02 Q45 engine knocking after about 2k miles on denso

[jamm220]

Well i guess its true and i learned the hard way. Before i even came on here i bought a 02 Q with 150k miles on i change the oil, diff, transmission fluid along with the air and cabin filter. I replace the old ngk's with come denso iridium (big mistake even though im not sure if this caused the problem). The engine starting knocking (not loud) but noticeable so i took it in. Cylinder #8 spark plug was bent at the tip of it kinda like the piston hit it. The tech also found a copper looking piece of metal on their and he said he could see where on the top of the piston was being hit. So now ill have to find another motor

[mtzgr777]

That's strange.....

[jamm220]

yes it is but im not blaming the plugs at all tho even though it make seems that way, i think more than likely there was something else lurking in there the labor to swap this motor is high as S$%T too

That's strange.....

[mtzgr777]

Yeah...it really does pay to be mechanically inclined....which unfortunately I am not (yet).

[Q45tech]

Depending on the quality and quanity of previous oil changes .....[every 90 days] many of these early engines were done done long before 150k.They redesigned the rings after 12 months but it didn't help much and the problem was corrected by 04-05 model engines.

Selecting an improper plug only makes the problems worse.

There are very significant differences between the 90-93, the 94-95, the 1996 and the totally redesigned more cost effective 2002.

If members don't have hands on and disassembly experience with 2002 engine avoid comments which may be appropriate for earlier designs.

Same thing with 2002-2004 G35 problems vs 2005.

[Q45tech]

I spent 8 Saturdays and Sundays working with regional and Japanese factory engineers at an new ATL dealer back in 2002 examining engines which were bad before the 2nd oil change.The just opened dealership service manager was 2 weeks before a T3 employee and had no clues about new engine design and development.

Obviously you didn't get one of the really bad ones. You might research the dealer records to see if you already have had an engine swap or two?

Not that that helps since after 100k you are on your own even with a engine replacement.

The 2002 Cima engine is just another reason I ignore the vehicles at not real Q's compared to the 90-95 engine. I avoid them like the plague.

I expect the new 5.0 liter will have some improvements. but you never know until you strip one down and measure things!CAREFUL as all the domestic junkyard engines will be bad and your only hope is a JDM takeout and then you are still iffy.

Adaptying a new 2005-06 or later is the best strategy.

[jamm220]

Depending on the quality and quanity of previous oil changes .....[every 90 days] many of these early engines were done done long before 150k.They redesigned the rings after 12 months but it didn't help much and the problem was corrected by 04-05 model engines.

Selecting an improper plug only makes the problems worse.

There are very significant differences between the 90-93, the 94-95, the 1996 and the totally redesigned more cost effective 2002.

If members don't have hands on and disassembly experience with 2002 engine avoid comments which may be appropriate for earlier designs.

Same thing with 2002-2004 G35 problems vs 2005.

hey what location do you work at? send me a number

[Skibane]

Unless the spark plug obviously knocked a hole in the piston or bent a rod (not too likely), are you sure that the engine is now permanently damaged? Seems like installing the proper plugs to see if the knock persists should be your next step - and would also give you an opportunity to check the other 7 pistons for damage.

[Q45tech]

I don't work at any facility. My main occupation is wireless telecommunications design and consulting and I have been on NICO for 7 years to flush my mind of wireless between breaths. Politics is a 2nd job doing research on candidates.

( moderate 3 other car sites and some wireless technical sites while my real computer is crunching big programs. As I yet I haven't put wireless comments on Nissan sites or politics etc.Helps me stay razor focused, I have 3 different key boards and monitors in front of me now. If I could type with my feet I could add 1- 2 more.

[qship96]

I dont think Infiniti "fixed" the oil burning{piston ring} issues with the VK4.5 in 05, as there are plenty of 05-06-07 model year complaints and engine warranty swaps still happening with both Q and M models.Crappy design and build,period.

[maxnix]

I think what Dennis was saying is that Nissan's later changes were more effective. As I dip in and out of the other Forums on NICO whose vehicles use the VK series, it seems like there are fewer complaints after 2004, but they are also fewer units sold and newer units, so less mileage.

OCI seems to be critical with any of these new stressed engines, and even some of the unstressed ones like the Toyota V6.

[jamm220]

i post a new thread, car is fix and the denso seemed to be the problem because after i replaced it with ngks it stopped knocking...thanks guysfor all your help

[Q451990]

That's good news! I feel sure some permanant damage was done, but if it's driveable and running well from all outward appearances at this point, you might as well drive it until something happens... could be 10K or 100K, so I would just try to forget about it and move on...

Did you happen to compare the length of the denso plugs you removed and the NGK you're installing? You might also want to check to see if you got one wrong Denso plug (too long) just to know what happened. Your warning to use OEM spec. plugs is a good one either way, but it would be interesting to know what happened anyway.

Heath

[jamm220]

That's good news! I feel sure some permanant damage was done, but if it's driveable and running well from all outward appearances at this point, you might as well drive it until something happens... could be 10K or 100K, so I would just try to forget about it and move on...

Did you happen to compare the length of the denso plugs you removed and the NGK you're installing? You might also want to check to see if you got one wrong Denso plug (too long) just to know what happened. Your warning to use OEM spec. plugs is a good one either way, but it would be interesting to know what happened anyway.

Heath

Update....I compared both plugs (denso n ngk) and they are exactly the same length so it gotta be something else. As far as the ngk, its running like it should now with no issues so that's a relief