Speed-related ticking sound

[Peter Chase]

A little while ago, my 1979 SC developed a "ticking" sound.

It seems to come from the middle of the car. I know these things can be deceptive, but I am at least sure it's not from the front. I really don't think it's a trim rattle/squeak.

The noise frequency varies with road speed, not with engine speed.

The noise is not loud, but is easily perceptible at moderate speeds. It is not metallic.

Everything seems to be working correctly and there are no vibrations accompanying the noise.

Any thoughts as to where I should look for a cause and remedy?

I have had a similar noise on a different car (can't remember which) and it was the speedo cable dying. Is this possible on an 911 SC? Does it even have a speedo cable (I see no mention of one in parts catalogues, so imagine maybe it's electronic)?


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[James Ball]

Hi Peter

Try this link:

http://forums.pelicanparts.com/showthread.php?s=db546a022c1670c217b69db17f220124&threadid=97658

Cheers, James


Migration info. Legacy thread was 3913

 

[Peter Chase]

Thanks for the article reference.

So, the Pelican Parts forum article suggests that the speedo is electronic, and indeed their parts list says "Electronic Speedo 1976-1989". So, I don't have a speedo cable noise, then!

The article refers to a ticking noise from an "OXS counter". What's that (sorry if I'm being dumb)?

Any other suggestions for a possible source of such a noise?


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[richard harrison]

they do not have a mechanical link to speedo which is good news if you are limited mileage Insurance, you have'nt anything wrapped around a drive shaft have you?

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[Peter Chase]

I should have finalised this thread earlier. I traced the problem to the handbrake. Something in there is making this noise. Haven't fixed it yet, but can generally stop noise by slightly applying handbrake while moving, then releasing it.

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[richard harrison]

Right the handbrake, is similar to the landrover design, in that it brakes via the transmission, so no handbrake turns unless you have extra deep pockets, you have most likely something trapped around a drive shaft after all, no great worry though, one for inspection at MOT should find it

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[John Brewin]

Have followed this thread with interest as I too have a 'rhythmic' noise associated with road speed on my '77 911 Sportomatic but only for the first few hundred yards from rest - after which it disappears completely until setting off again from low speed.

Similar symptom in that mine also sounds like it comes from the 'middle of the car' For this reason I hadn't made the connection with the handbrake but will certainly be investigating this further.

Richard Harrison mentions 'transmission handbrake' - on a 911?? As far as I'm aware it's a combined disc/drum assembly acting directly on the hubs as in most other vehicles.


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