my 2005 w/ 195k miles on it has been making quite a bit of timing chain noise for the last few months. I was positive I needed to do some work on it but was dreading all the labor to get it done.

a few days ago, on the drive home from work, the engine starting having some real issues at idle and was stumbling on acceleration. I was worried I had a major timing issue (skipped tooth and bent valve maybe?) and decided it was now or never to open up the case and investigate the timing chain.

The tensioner shoes on the secondary chains were completely worn down. Those chains were riding on the metal plunger of the tensioners.

The main tensioner lever arm was also missing some plastic (probably down in the oil pan now) and the main chain was rubbing against some metal on that arm also. That's probably where all my noise was coming from at startup.

Probably the most interesting part of it all was I was missing a tiny o-ring that seals an oil passage port that affects the variable valve timing. Our VQ engines use high-pressure oil to change the timing on the valves (and also the lift duration). I think the oil was squirting out into the main timing case and not fully pressurizing the cam, and thus not causing the VVT to work as well as it could.

Anyway - got everything is back together and the truck fired right up. I was really happy and the timing looks to be exactly right (was nervous about that part). Drove it around the block and the engine starts running rough and stumbling again - crap!

Finally threw a code - p0304 which is a misfire on cylinder 4. Ended up being an ignition coil boot, the spark was getting out of the boot and grounding to the engine. $10 later at the parts store and now the truck is totally amazing.

way more power than ever before, and over the last 2 days, I'm seeing another 2mpg on average. super quiet at startup/idle, butter-smooth on acceleration, and if you really give it some gas I can feel the VVT kick at ~ 3500rpm as the truck pulls.

I'll try to get some pictures posted of the tensioner shoes - the wear was impressive.

Awesome!!! Talk about a success story!!

Do you have any specific tips on other who might tackle that job?
Any more pics?

the ocho wrote: Probably the most interesting part of it all was I was missing a tiny o-ring that seals an oil passage port that affects the variable valve timing. Our VQ engines use high-pressure oil to change the timing on the valves (and also the lift duration). I think the oil was squirting out into the main timing case and not fully pressurizing the cam, and thus not causing the VVT to work as well as it could.

If you're talking about what I think you're talking about, it sounds like a.) someone did your tensioners before and b.) might have used the wrong parts. It's not an o-ring but a Nissan specific material seal that comes with the timing chain covers (the little panels in the front cover itself, there may be similar seals on the back side). Yes, it maintains oil pressure for VVT.

What happened with mine was the dealership that did my tensioners (did not replace chains) in 2009 used o-rings to replace the seals. One failed over time and VVT stopped working on that side. Dealership that did my chains and tensioners the second time a couple weeks ago replaced those seals with the correct Nissan parts, which only come with the whole cover.

If you replaced the o-ring with another o-ring and not the Nissan timing cover, then it will fail on you again over time. If you search the other Nissan forums you will find other examples where this happened to other owners.

You also probably had the same thing happen to your truck as mine. In the early days of the TSB, they replaced the tensioners but not the chains, and over time the same chains ate into your tensioners and guides.

way more power than ever before, and over the last 2 days, I'm seeing another 2mpg on average. super quiet at startup/idle, butter-smooth on acceleration, and if you really give it some gas I can feel the VVT kick at ~ 3500rpm as the truck pulls.

Yup. If you use Nissan DataScan II on your phone, and an ELM327-chip containing OBD II Bluetooth scanner, you will be able to see VVT actuate with CONSULT data. Importantly, you will be able to see if both cams are actuating or not. After my chain fix I got a code for timing advance but the truck felt pretty good. Only got the right problem with NDS.

VVT is active across the RPM range based on throttle vice RPM like Honda's original VTEC or others. It turns on when coolant is above 130 degrees F or so and you can feel it smooth out. FSM test for VVT (and cam timing) is zero plus or minus two degrees at idle and at operating temperature, and zero to plus thirty degrees advanced out of phase at 2,000 RPM.

I didn't take many pictures - but it's a pretty involved process. I found a great video on youtube - https://www.youtube.com/watch?v=j3uY3clWxFE


here are the pictures I have:
https://photos.app.goo.gl/SHkC9nu2dwkXgrHv9


you can see in this photo the o-rings. Look just to the outside of the main cam gears. on the right, you can see where the existing cracked/solid o-ring is and on the left, where one was missing.



btw - the o-rings were purchased from Nissan (at $7 each!) at their parts counter. They fit perfectly so I'm hoping they are the correct part.

it was this part:
https://www.nissanpartsdeal.com/parts/n ... 2y510.html

ShipFixer wrote:VVT is active across the RPM range based on throttle vice RPM like Honda's original VTEC or others. It turns on when coolant is above 130 degrees F or so and you can feel it smooth out. FSM test for VVT (and cam timing) is zero plus or minus two degrees at idle and at operating temperature, and zero to plus thirty degrees advanced out of phase at 2,000 RPM.

That's probably what I was feeling - (the time from the engine going from 2000 rpm to 3500 rpm is probably about the same time it takes for me to look down at my gauge cluster and say "crap this thing is really pullin!"

Different seals then. Looks like you got the correct ones, which are teflon instead of rubber o-rings. The ones I had replaced were in the timing covers themselves (13041-8J10A) along with another set (15066-5E510).

VVT sure does make a difference though. I'm pretty happy with how smooth my engine is, I don't recall it being this good, and the original repair was in 2009. It was also pretty nice to effortlessly pull away from the Tahoe that tried to cut me off on an uphill the other day