So I just had my clutch and flywheel changed with CMAK and new driveshaft (1-pc)…and installed a short shifter a week earlier. So trying to narrow down possibilities as to why now.

Now I know a new lightweight flywheel will whine/chatter a bit more, but this sounds like grinding metal/rocks. Maybe a throw-out bearing or my shifter is in a bad spot cause it sits low. It just doesn’t seem consistent for everyone.

 

I just want to say….I hate this thread was hi-jacked to diagnose a different sound.

The sound was originally a cement truck grinding metal sound at low rpms.
Not a rattle/knock sound.

I wonder how many people will change their gallery gaskets to fix this original noise.

 

so you're saying the original sound is not related to the gallery gasket??? I just bought the kit lol, but I ll test the pressure first. but any idea where the original sound comes from?

 

Honestly, I’m still not sure and figure the gallery gasket is a long shot guess….but its better than doing nothing. Honestly, it seams like a heat shield or a loose metal piece/bracket that’s just rattling when the engine is vibrating more violently. Like accelerating at low RPMs. The gallery gasket feels pretty far removed. But it will eventually need changed, so I’d like to here your findings. If it sinks the noise, then I’m in.

 

Have this same sound. Goes away under 1000 rpms and above about 1500 rpms. Been chasing it for some time

 

I hope its just frequency/vibration issues. Let us know if you find anything.

 

This thread was recently been brought back to my attention from Reddit since last reading responses from around early 2021, and I wanted to share my findings that contradict the current popular presumption that this is solely an oil gallery gasket issue.

My conclusion is that this is an issue with overly-advanced factory ignition timing during conditions of taking off from a stop or being in a high gear and driving uphill, which both derive from a high load + low rpm condition. The result of the advanced timing is the sound, which is without a doubt the sound of your engine pinging, mildly knocking, or otherwise exhibiting the symptoms of low-speed pre-ignition.

My conclusion is supported by the fact that I have replaced the engine (with gallery gasket job and all new timing including intake cam phasers and VVT solenoids), have done a VR30 transmission swap, FBO spherical suspension, and replacement of the entire power steering circuit and serpentine belt accessories.

It still happens, lol. 💇‍♂️

In summary, its not something that even the dealership can resolve, but can be fixed via specified tuning being a timing issue. Though zero knocking/pinging is ideal, IMO the conditions by which it occurs do not cause meaningful wear or damage to your engine, as supported by the teardown of my original engine that experienced the rattle for about 20k miles.

There is a suggestion that flashing/resetting your ecu which clears its memory cache for adaptive learning (variable valve timing, VVEL fuel trim, throttle bodies, etc.), restoring the time base map that has not yet run away with advance. But since you can't just turn off it's closed loop timing algorithm, this is solution is only temporary. The ecu can be reset by the unplugging the battery, or can easily be done in the ecutek app for the ecutek-tuned.

In considerstion of how the gallery gasket flaw may be involved, the intake cam phasers are spring loaded to its peak/near-peak state of advanced timing by default (little or no oil pressure fed by the VTC solenoid). If there isn't enough oil pressure at the lower rpms for any reason including a compromised gallery gasket, cam timing may remain excessively advanced for a short period of time. There are a few claims I have read but cannot verify that excessive cam timing advance can produce a cylinder environment that is conducive to pinging for some engines, but the instances are far more rare than cases of overly advanced ignition timing that would be linked to insufficient oil pressure.

Here's my write-up that I shared a few days ago on Reddit for further details about this issue and its symptoms. Let me know what y'all think.

https://www.reddit.com/r/G37/s/gIgUBkAWwk

 

I've had this noise on mine for a while now and i know its not cats or heat shields because i have isr long tube headers. Glad i read the last post saying it doesn't mean death for the engine, i was getting ready to take it somewhere and was quoted $2500 for timing chains and tensioners. Got other issues to take care of so i can put that money elsewhere now.

 

You know…I kept meaning to watch my timing but because I have a handheld OBD2 reader instead of something better, its hard to watch the rattle and drive the manual. I would think the car/ECU would eventually learn and adapt that range. I’m also curious how many cars have been tuned differently. Maybe Infinity programed the ecu to balance this phenomenon….and we tuned it out. I doubt its a tune….I had a tune for almost 7 years and no issue until I swapped my flywheel/clutch/slave. I wish I could put it back on a lift with someone driving it to see if I can hear it….with the wheels in motion not just revving. Either way I could watch the timing and/or listen for the sound. I would love to see someone else confirm the timing.

 

The above sample of one undamaged engine is not suitable to draw your conclusion. Light pinging (barely audible for short periods of time) is okay but detonation (different from pre-ignition) is not good for pistons or ring lands. Were I to hear loud or extended periods of detonation, I’d downshift to relieve the load as I accelerate through the troublesome speed range, then reconsider the gallery gasket replacement. Stupidly expensive but better for the engine. Are you running 91-octane gasoline?

 

I'm running 93 for my z1/ecutek tune. I'm not familiar with what pinging sounds like but my noise sounds like a loose chain rattling at low speeds. I don't know if the $2500 i was quoted was average price or not for timing work on these cars but there's no way i can come up with that kind of money any time soon.

 

Your price is on the lower end of the range from what I recall of this repair. It’s not happened to me yet (70k miles) and dread the thought of it happening.

 

Hi, ths is 2025 and I am having this issue, basically this issue sounds as if gears grinding. My car has been looked at by 2-3 mechanics. I believe it is the AWD System. Basically the AWD version of G cars operate in a RWD basis and then engage the transfer case when ground is unstable or etc for better traction and performance. I believe the issue is either a transfer case or front diff because if it was the engine it would do this knock when accelerating in idle or neutral. Also i does not sound like the transmission for me because when I am on a flat road and floor it the car shifts through all the gears fine. So yes not exactly sure what is wrong but it sounds like a AWD system error just because my symptoms only happen at low RPM when accelerating or making a left turn and only left turn at a light. In RWD model you only have a transmission -> drive shaft -> diff -> wheels in AWD I believe it is transmission -> transfer case -> drive shaft -> diff -> wheels and decides to send power to front wheels which is what causes the grinding when the car engages the AWD system otherwise it usually stays in RWD but when car is loaded the computer changes the spin of each wheel. I don't know of that makes sense but this is literally the last thing the mechanic can check. I have ran through alot of stuff through my head and I drive a 2015 q40 (basically a g37 with new name) so if your above 2012 it would be rare that the oil gallery gaskets go bad to cause this grinding sound. And further confirms my idea because one you get to driving normally like 30-40mph mine won't do it. Only happens when I believe the AWD system is engaged. I love technology but damn can things just be built tough to last so tired of over complicated things taking out cars especially modern cars. TLDR I had a RWD g35 with 240000 miles loved that car and not a single issue besides basic wear items that went bad that were easy to replace and change battery alternator water pump etc but no major systems went bad. Engine transmission and other "advanced" systems still intact and I drove it like I stole it. Funny enough it ended up getting stolen... that is my two cents hope this helps someone down the road LOL voicing my frustrations since it is probably a $2000 bill! YAY!

 

For what its worth my engine got severely damaged last summer (due to my negligence swapping the transmission) and when i pulled the engine apart i had a tensioner that no longer had any tension so it was the timing chain rattling.