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Amazing that people accept the status quo without desire to understand the why.
I have no problem if someone wants to attempt to figure out the "why".
In my case, I noticed the engine rattle soon after picking up my 996 Turbo new from Jim Ellis Porsche here in Atlanta. I took the car back to them and their lead mechanic listened to the noise and immediately said "That's normal, all 911's make that noise to some degree". That was good enough for me.
I totally understand the desire to try and figure out the why but I agree with Mark, Dock, s65e90, others. It's a pretty well known fact that these motors have a unique sound. I think I read that folks have actually tried to chase the noise down, replacing parts, etc and not been able to resolve it.
I check my oil filters, do regular oil changes and most importantly the engine runs very smooth and strong as heck!!
There is a cure for that. Have you looked into it?
Yes, a twin 60mm turbo forged LS3 would definitely fix that problem, and if you would like to fix the German engineering , I have heard that removing the transmission and fiddling and or replacing the crank sensor to the correct gap may fix the problem. Not decided on which fix to do
The first time I heard mine start, as it was being backed out of the transporter, I about fainted. Now I run 5w40 and the noise, while still there at startup goes away in half the time and I no longer get the low oil warming light during "spirited" driving sessions.
Marbles in a blender is the perfect description of the glorious noise at startup.
Amazing that people accept the status quo without desire to understand the why.
The engines left the factory without rattle, now most (see youtube) rattle. They all sound like mine. Some don't rattle at all. Interesting, no?
People have various explanations from "Hans Mezger designed it, therefore it is ok if it rattles" to chains to IMS. That's not specific enough for me. I'm just curious if anyone else has taken the time to really identify the source of the noise.
How do you know the engines were quiet when they left the factory but got noisy later?
ID'ing the source of the noise is pretty easy. An internal combustion reciprocating flat 6 with a gear drive (with no lash eliminator) between the crank and the lay shaft with the lay shaft in turn through long chains that drive the exhaust cams each of which use a chain drive to spin its intake cam.
This in a 3.6l 6-cylinder engine turned to deliver 420hp. Compare this to for instance my 2006 GTO with a 6.0l engine that delivers 400hp, with I might add just 2 valves per cylinder and overhead valves at that. (As a result it was a pretty quiet engine as engines go.)
Really, that the Turbo engine is noisy is not surprising. If it were *not* noisy that would be surprising.
I don't "accept that something is wrong" -- I assume it made that sound when it left the factory. If I am wrong, would be curious to know that. I love how my engine sounds.
Someone a couple years ago on this forum tore the mezger engine down to address this issue. He did everything he could think of, even used GT2 IMS gears etc, chain tensioners, new IMS bearings, etc with other things! Started it up noise was there!
Moral of the story, its not an issue, lets just put all this to bed!
Someone a couple years ago on this forum tore the mezger engine down to address this issue. He did everything he could think of, even used GT2 IMS gears etc, chain tensioners, new IMS bearings, etc with other things! Started it up noise was there!
Moral of the story, its not an issue, lets just put all this to bed!
It's not an issue, rather a quirk of the engine. The person you mention above has before/after youtube videos where you can hear that the rattle is gone after the rebuild. However, based on his comments, the rattle was quickly back.
I don't mean to spoil your ownership by badmouthing the sacred engine (it's not going to blow because of the rattle).
I just found that the source of the noise seems to be near the main oil pump and I would like to know if others have found the same.
It is possible that the backlash of the IMS gear (the whole IMS has quite a bit of axial play) causes the oil pump drive (floating hollow shaft) or the oil pump itself to rattle.
If no one else finds the noise coming from the area of the main oil pump I may have a unique engine.
Where do you think those mysterious slivers of aluminum come from in random oil filters? These are not coming from main or rod bearings, nor cylinder walls, not camshaft or lifter related. Maybe chains slapping against the housing?
No idea, if your tensioners are bad the chains could slap but based on what I read you would also find bits of plastic (chain guide) in your filter.
Also, if the chain was slapping you would easily find out by using a stethoscope.
The engine is so complex that there are plenty of causes for rattle. Then there is the cold startup rattle, flywheel rattle and the rattle that develops once the engine is hot and is audible between idle and 2000 rpm. I'm chasing the latter.
Yes, a twin 60mm turbo forged LS3 would definitely fix that problem, and if you would like to fix the German engineering , I have heard that removing the transmission and fiddling and or replacing the crank sensor to the correct gap may fix the problem. Not decided on which fix to do
04-06-2017, 04:47 PM
