Mysterious Tachometer

911_rs74 · 07:15 AM

Hello everyone,

It's my first post so thank you all for the advices and informations we can find on
pelican.
I have a question about my tach, I did a lot of research but I know there's people with
big Porsche knowledge here, so better ask.
My car is a 2.7 from December 73, one of the first 2.7 out from the factory.
All my gauges are stamped 07.73 so it seems that they used existing models maybe and my tach is an early style with black center

never seen a tach like that and I don't think it was open. I'm the third owner.

Have you ever seen something like that ?

Thanks

RC

jbell959 · 03-20-2021, 07:53 AM

Interesting... Never seen one like that before. Porsche is known for using up the old stock in transition years but that wouldn't really explain this one. It's the correct tach for a 2.7 with the high-beam indicator up top but it has the early needle with the silver button painted black. If it were a left over 73 tach the high-beam indicator would be at the bottom.

My guess is that it was opened up at some point and the needle what replaced, but nothing surprises me anymore. If it was done at a shop with the VDO tool to crimp on a new bezel you wouldn't be able to tell if it had been opened.

I'd be interested to know if anyone has seen another one like this.

304065 · 03-20-2021, 07:54 AM

Cant' tell anything without seeing the back of it.

jbell959 · 03-20-2021, 07:57 AM

Also, what is the part number printed on the upper lip of the face?

proporsche · proporsche's Garage

RC.go to the French forum if you are not already member and ask for Gedeon25 he is an expert in France for gauges;-)

type911.org

or you can find him here
stationcompteurs

Ivan

proporsche · proporsche's Garage

here is similar 1974 911S

jbell959 · 03-20-2021, 08:36 AM

Quote:

Originally Posted by proporsche

here is similar 1974 911S

Cool.. Never seen a speedo like that either.

RC: Does your speedo have the same needle with black center?

911_rs74 · 09:18 AM

Quote:

Originally Posted by jbell959

Cool.. Never seen a speedo like that either.

RC: Does your speedo have the same needle with black center?

Thanks for the reply guys

No it's just the tacho, the speedo is the normal version for 2.7

Part number is 911 641 301 29 - 0001

This is a picture of the back

proporsche · proporsche's Garage

RC,it is very possible it has been apart ..the markings next to the screws..otherwise very interesting tacho ...

Ivan

911_rs74 · 03-20-2021, 09:46 AM

Quote:

Originally Posted by proporsche

RC,it is very possible it has been apart ..the markings next to the screws..otherwise very interesting tacho ...

Ivan

Yes it's the most likely scenario I guess

proporsche · proporsche's Garage

But,very nice piece and it is good to have something different..;-)

Ivan

304065 · 03-21-2021, 06:42 PM

So you have a tach made before the August factory closure, which would have been a 1973, and your car was made in December which makes it a 1974.

There is usually a witness mark of paint on the screws- that and the scratch marks around the screw heads and distortion of the slots suggest this tach was opened at some point for repairs, and the needle was replaced.

here's a photo of an early 74

https://www.caranddriver.com/photos/g17972433/1974-porsche-911-vs-911s-targa-911s-carrera-archived-comparison-test-gallery/?slide=29

911_rs74 · 03-22-2021, 07:02 AM

Quote:

Originally Posted by 304065

So you have a tach made before the August factory closure, which would have been a 1973, and your car was made in December which makes it a 1974.

There is usually a witness mark of paint on the screws- that and the scratch marks around the screw heads and distortion of the slots suggest this tach was opened at some point for repairs, and the needle was replaced.

here's a photo of an early 74

https://www.caranddriver.com/photos/g17972433/1974-porsche-911-vs-911s-targa-911s-carrera-archived-comparison-test-gallery/?slide=29

Thanks for your answer, I found a picture of a black center early tach on a post,

maybe I will ask what's the story behind.

Ian Comerford · Ian Comerford's Garage

I notice your car has a 3.0 engine so maybe the tacho was swapped out for another to make it work ok with that engine?

jbell959 · 03-22-2021, 07:16 AM

Quote:

Originally Posted by 911_rs74

Thanks for your answer, I found a picture of a black center early tach on a post,

maybe I will ask what's the story behind.

That one is an earlier tach evident by the ivory versus white face. 68 through sometime in 71 were that off-white color.

911_rs74 · 03-22-2021, 09:09 AM

Quote:

Originally Posted by Ian Comerford

I notice your car has a 3.0 engine so maybe the tacho was swapped out for another to make it work ok with that engine?

No I swapped the engine recently but it had a 2.7 since the beginning.

LJ851 · 03-22-2021, 02:38 PM

The tach in my car is nearly identical. It has the same face, same part number but has a 7/75 build date.

The needle is the newer style like you would expect and the labels for each electrical terminal are cast into the plastic not printed on the metal housing like yours.

Walt Fricke · 03-24-2021, 02:44 PM

This was a real 2.7RS, and you put a 3.0 in it?

911_rs74 · 03-25-2021, 01:49 AM

Quote:

Originally Posted by Walt Fricke

This was a real 2.7RS, and you put a 3.0 in it?

No just a common 2.7

Walt Fricke · 03-25-2021, 03:28 PM

When I put a 3.0 into my '77 Euro 2.7, I was advised to change my tachometer. The earlier tachs got their signal from the distributor points. When the points went away, the six pin CD box had a dedicated (and cleaned up) tach output - a pretty clean 12V square wave. This supposedly would not work with the original tach, and an SC tach was what was recommended (which I did).

But you have an even earlier tach, so this doesn't quite make sense. My suspicion is that you can't easily convert these by changing some passive electronic components inside the tach, but maybe you (a knowledgeable shop) can?