Nissan 370Z Forum - View Single Post - Valve Cam Brackets Broken? Chasing down the tick...

loon · 02-08-2023, 02:11 PM

Hey guys, might be long but this one has been alot for me.

Back in December after a few cold days (rare down here in FLA) I started randomly losing power, like the engine would climb rpms but there was no speed that came along with it. Thought it was MAF at first, replaced the sensors, the problem came back the next day. Cleaned the throttle bodies... the problem came back 3 days later. Changed the spark plugs, same story, came back the next day. So i determined it was heat sensitive, came back from vacation after my AHA moment realizing it was probably the fuel pump. That it was.

Changed the fuel pump and then took it up the next day to Sebring for a track day, on the second lap of orientation I got a fatal loss of power and ticking

Now I'm here trying to diagnose it.

Took the valve cover off and the only thing strange that I found was this:

https://imgur.com/XqPu0pu
https://imgur.com/pbu1mTJ

(Sidenote youtube was forcing me to use shorts because it's such a short video, kinda weird but w.e)

It looks like the valve cam bracket is slightly damaged where it mounts to the head. It's much worse on cylinder 1 than on 3, and 6 looks undamaged.

Additionally the VVEL linkage arm (which I can't find anywhere what to call it because NISSAN doesn't sell or identify this part individually) has way too much play, especially compared to the other two cylinders

When looking down the intakes it is clear that cylinder 1 has a significant amount more carbon buildup than any other cylinder. Images probably not necessary...

Last note, I checked codes AFTER taking the intake plenum and everything off and got P0603, P0123, P0228, P2133, P0223. But those are all overvoltages on each TP sensor + a ECU fault that could have realistically been from disconnecting the battery in a weird way.

SO... cylinder 1 is probably a problem? but I haven't has misfires since I changed out the fuel pump. The ticking doesn't sound like rod knock and I'm still technically able to drive with whatever the problem is (I was able to drive off the track, then to the front gates to be towed with no problem) of course with no power. I'm fairly confident that the problem isn't rod knock, so the only other thing MUST be the valves, and well... the furthest I've got with that is the above pictures, think that's the cause?

02-08-2023, 02:11 PM	#1 (permalink)
loon Base Member Join Date: Jan 2023 Location: FL Posts: 31 Drives: 2014 z34 Bl M6 Rep Power: 547	Valve Cam Brackets Broken? Chasing down the tick... Hey guys, might be long but this one has been alot for me. Back in December after a few cold days (rare down here in FLA) I started randomly losing power, like the engine would climb rpms but there was no speed that came along with it. Thought it was MAF at first, replaced the sensors, the problem came back the next day. Cleaned the throttle bodies... the problem came back 3 days later. Changed the spark plugs, same story, came back the next day. So i determined it was heat sensitive, came back from vacation after my AHA moment realizing it was probably the fuel pump. That it was. Changed the fuel pump and then took it up the next day to Sebring for a track day, on the second lap of orientation I got a fatal loss of power and ticking Now I'm here trying to diagnose it. Took the valve cover off and the only thing strange that I found was this: https://imgur.com/XqPu0pu https://imgur.com/pbu1mTJ (Sidenote youtube was forcing me to use shorts because it's such a short video, kinda weird but w.e) It looks like the valve cam bracket is slightly damaged where it mounts to the head. It's much worse on cylinder 1 than on 3, and 6 looks undamaged. Additionally the VVEL linkage arm (which I can't find anywhere what to call it because NISSAN doesn't sell or identify this part individually) has way too much play, especially compared to the other two cylinders When looking down the intakes it is clear that cylinder 1 has a significant amount more carbon buildup than any other cylinder. Images probably not necessary... Last note, I checked codes AFTER taking the intake plenum and everything off and got P0603, P0123, P0228, P2133, P0223. But those are all overvoltages on each TP sensor + a ECU fault that could have realistically been from disconnecting the battery in a weird way. SO... cylinder 1 is probably a problem? but I haven't has misfires since I changed out the fuel pump. The ticking doesn't sound like rod knock and I'm still technically able to drive with whatever the problem is (I was able to drive off the track, then to the front gates to be towed with no problem) of course with no power. I'm fairly confident that the problem isn't rod knock, so the only other thing MUST be the valves, and well... the furthest I've got with that is the above pictures, think that's the cause? __________________ Black 2014 370z Sport Touring MT \| FortuneAuto 500s \| 25mm Rears 20mm Fronts \| Invidia Gemini Exhaust Last edited by loon; 02-09-2023 at 11:11 AM.