Can I make this 65 911 QUIETER??!!

[jrtaylor9]

I’m a long time Porsche nut that has owned a bit of everything up/down the various generations including a few early 911s. I just got back my 1965 full mechanical rebuild. It was an amazing job. I have one of those questions/comments that I usually laugh and poke fun of owners for asking. Additionally, I don’t think I’ve EVER asked to make a car quieter; only louder!

I’ve attached a couple of clips. Every AC’d 911 I’ve owned has had a high pitch whine that cuts through the exhaust note at times. I have owned two 2.0’s before. I don’t remember anything having such a pronounced high pitch whine/shriek that shouted over the top of all other noises.

I’ve never known what creates the signature ac 911 high pitch howl: fans, intake, other? Is there anything that can be done to tone it down in my otherwise perfect 1965 w/out knocking out all the other quieter, good noises (sound deadening)? Or do I need to come to grips with tinnitus or selling my dream fully sorted 1965??

https://youtube.com/shorts/FljECx6Ve0o?feature=shared

https://youtube.com/shorts/biQ5tdFDz2I?feature=shared

[TheTorch]

Hard to tell from the video, but that sounds to me like a transmission whine from worn gears or possibly ring and pinion. Gears you can tell if they abate when in neutral or different pitch in different gears.

If you rev in neutral while not moving, does it whine?

[moito]

Hard to tell from the video, but that sounds to me like a transmission whine from worn gears or possibly ring and pinion. Gears you can tell if they abate when in neutral or different pitch in different gears.

If you rev in neutral while not moving, does it whine?

was thinking the same

[Scott A]

I wanted the same thing, a more quiet 911.

At first, I rode around with some sound cancelling headphones.
That was effective, but a little too much fiddling.

But the high pitches and noise was just too much for me to enjoy the car.

Then later, I really started to go after it.
The easy things were more sound seasoning behind rear seats.
I looked for every hole.

I tried a German super quiet oil additive, which is very thin. That didn’t work well.
I put in 3+ quarts of Lucas oil stabilizer in oil. That worked a lot!
I put in half Lucas in my tranny, that helped a lot!

Whenever I change my oil, there is not any metal on the magnet.
So I feel comfortable with it.

I rebuilt my differential, with lots of measuring and a little trial and error with those shims, (you can feel when it too tight, but you have to get a feel for it)
I rebuilt the inside of my spider gears. So they were tight.
All that reduced 50% of the tranny noise.

Now, I never wear ear protection, and I never get fatigue, like I did before.

Using a stock, tho may be sport, 1971 muffler.

And I have experimented with 1980s, oil filled, chain tensioners and solid set screw types.
The set screws were more quiet, the oil ones were always making little chain noises.

My friends 911 same year with loud muffler is ALL noise.
My car felt about 45 years newer, cause all the noise was reduced, more than 60%, I think.

[jrtaylor9]

Hard to tell from the video, but that sounds to me like a transmission whine from worn gears or possibly ring and pinion. Gears you can tell if they abate when in neutral or different pitch in different gears.

If you rev in neutral while not moving, does it whine?

You are right that’s what it sounds like but that’s not it. There are two videos; one says “under load”; the other doesn’t; to demonstrate it’s not transmission whine. Yes, I can hear a tiny bit of that transmission whine you reference but it is minimal and only in gear. This whine is there revving in neutral every bit as much as in gear; if anything you can hear it better in neutral but revving the engine.

[jrtaylor9]

Sounds like I have a lot of possible issues to troubleshoot and experiment with. It would be too much to ask for it to be something like a bearing that is faulty. I’m afraid it’s another slippery slope of potential trial and error fixes. Hopefully not.

[Scott A]

I didn’t listen too perfectly to your video.
But,
One time I was driving around 35mph.
I was driving by some houses on a country road. I heard this noise, I thought it was an 8 year old girl screaming.
I thought maybe someone screaming in a yard, But the sound just kept with me for the next 1/4 mile.
It was then I realized it must be a bearing, which it was the right rear.

Watching/listening to your video, I can see the car is not moving, so…

[TheTorch]

with the trans ruled out, I would get a friend with chassis ears, or a stethoscope, or a tube to listen to parts of the engine while revving. Start near the alternator. You should be able to narrow down what part of the engine is making the noise.

[jrtaylor9]

Thanks. I’m on it. I’m actually relived the feedback is that it doesn’t sound “right”. I’m pretty sure any similar tone noise I’ve heard in prior cars was transmission and this isn’t that plus it’s 10x as loud.

[Scott A]

I think one thing you could do is disconnect your fan belt for a short time.
That way you could rule out the fan and bearing and belt and alt and those parts.

And if things get quieter, then you know to look at those parts as the problem.