Can I make this 65 911 QUIETER??!!

[jrtaylor9]

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.

Listening to the motor from the back, it sure seems like it’s something related to the fan. Who thought something like that could drown out a 2.0! I’ll report back with what I found but needed a gut check to confirm I wasn’t crazy.

[Boulder Bob]

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.

can you please post a link or give more information on these additives?

[Boulder Bob]

on my stock '73 - I notice a big change in intake sound when I run without the air temperature regulator

also, with the top on, wind noise is the most fatiguing factor for me

[Scott A]

It was a few years back, but I’m pretty sure I put this liquiMoly in.
Recommended from a 40 yr Porsche mechanic.
It might be great for your engine, I don’t know, but I didn’t like it.
I was hoping it would make it quiet, but it did not.


The stuff I really like is Lucas,
(surely some hate it, but I have used it for 40+ years)
I couldn’t handle the noise and so I tried this Lucas.
I live in a hot climate, so I don’t worry so much about cold starts.
It made a very significant change to the motor noise, and also the tranny noise, it knocked out the high noises.
Personally I use 3+ quarts.
Also, my engine never runs hot.



I also run Valvoline VR1 20/50 .

My gear oil is shell spirex.


Take out the fan belt and see what you hear.

[srogebry]

Are you running solex or weber carburetors?
Would love to see some pictures of the car. The interior looks very nice in the short video.

[Haasman]

Almost sounds like an alternator whine to me. How about revving the engine, while in place with the engine cover is open. No driving.

[jrtaylor9]

Are you running solex or weber carburetors?
Would love to see some pictures of the car. The interior looks very nice in the short video.

I’m running solex. I’ll send more pics when I get it back. The guy that did the rebuild has it and I haven’t followed up but I expect I’ll have it back shortly.

[jrtaylor9]

Almost sounds like an alternator whine to me. How about revving the engine, while in place with the engine cover is open. No driving.

I agree that’s what my opinion is with plenty of expereince driving these cars but not so much turning wrenches on them. It’s back in the hands of the guy that is more than competent at chasing it down. I decided that was the best course of action once I confirmed I wasn’t over-reacting to what my ears were telling me.

[jrtaylor9]

I’m back. The car runs amazing; truly amazing for a 1965 911. Everything “checks out” mechanically, it’s not alternator, belts, nada. It even has dynomat already in the back. However, this high pitched wail resonance sound is still there and it’s not as I have experienced hearing early 2.0 swb cars in my past. I’ve had a couple of people suggest it could be a result of swapping oem for ssi stainless header/heat-exchanger. On one hand I want to try it given I’ve heard that suggestion 2x now. On the other hand, don’t a LOT of people replace oem header/heat-exchanger with ssi stainless setup? And if so, I can’t imagine anyone not complaining about what I’m hearing. The oem soundtrack is there, it’s just accented/over-shadowed by a foreign wail that doesn’t belong.

[frederik]

My Targa had a similar high pitched wail which I always attributed to the MFI. Until I got my current 2.2S which is way quieter and doesn’t have the wail. Very similar to your video. In my Targa, this sound was the same before and after its engine rebuild. My best guess is maybe the camshaft gears in combination with the chain, or the intermediate shaft gears. Both are very expensive to try and renew unfortunately.

I don’t think it’s the exhaust or heat exchangers. I had SSIs on my Targa and have them now on my 2.2 so that’s definitely not it.