Jrtaylor9

I’ve owned a bit of everything up/down the various P 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??





I frequent RL more often but I also posted on early911 given it’s an EARLY 911.

raspritz

Neither my '67 2.0 S-spec racecar nor my '69 2.0 S-spec street car make such a howl. What an awful sound! Something is wrong with your car!

Jrtaylor9

Believe it or not, it’s a relief to hear that. Now the quest to figure out wth is causing it.

rstarga

Ring and pinion wear or misadjustment?

theiceman

that is sounds like its coming from the gearbox for sure...

kind of reminds of the sound you get when you are reversing at higher speed.

Jrtaylor9

I would agree it sounds like that tone from a gearbox but it’s there when I rev in neutral as well which is one of the two videos. Absent that I totally agree that’s what it sounds like.

Vane

I would pull the fan belt and check. Very easy to do.
The fan / fan housing has quite tight tolerance and the housing is in at least 3.2 very weak and iron the crack.

theiceman

try it with the clutch in ... that way the engine is disconnected from the input shaft of the gear box, see if it still does it .. then you have halved the problem on way or another..

Jrtaylor9

I’ll give it a try.

rstarga

If it does it without being in gear it could be your alternator bearings.
Take the belt off and see if the sound is gone.

Spyerx

Man I love the sound of a 2L

I am pretty sure that is NOT the trans, but it's easy enough to tell, just do what you did at idle and engage the clutch. Since my regear and putting much firmer trans/engine mounts in my car I get a little more gear/shaft whine on my 901, and it doesn't sound like this at all.

I am with the others, pull the fan belt and start car (for just a few seconds) and see if it continues. I suspect alternator whine.

Jrtaylor9

It’s with the guy that did the rebuild. I’m sure he’ll sort it but if he hits a dead end, this thread has given me plenty of ideas. His suspicion was alternator as well. It’s not the trans.

Spyerx

post some pics when you get it back. and a couple redline pulls :-)

Jrtaylor9

Will do!

theiceman

well if the clutch trick told you its not the gearbox then alternator is definitely the next cuprit. I hate that job , Porsche could have given us just 2 inches more wiring .. what a PITA