Last 2 10k tachos ...

Lightweight_911 · Post by **Lightweight_911** » Wed Jun 08, 2011 4:27 pm

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1) 10k tacho as used in many of Porsche's competition models including 911R/ST/2.8 RSR, etc.
Unused since conversion/refurbishment by North Hollywood Speedo

Dated 1/'68 but fits all '65-'73 (& later) models

Has one tiny (pinhead-sized) mark on rim at bottom:

£300 including P&P - SOLD !!!

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2) Another dated 2/'70 but has cracked glass needing replacement:

£250 including P&P

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911_2.2T · Post by **911_2.2T** » Thu Jun 09, 2011 9:50 pm

Are these for 3 pin or 6 pin CDI boxes?

Lightweight_911 · Post by **Lightweight_911** » Fri Jun 10, 2011 10:04 am

Alex - they should work with either ...

Mick Cliff · Post by **Mick Cliff** » Fri Jun 10, 2011 10:16 am

Lightweight_911 wrote:Alex - they should work with either ...

I wouldn't bank on that - sorry Andy

Lightweight_911 · Post by **Lightweight_911** » Fri Jun 10, 2011 6:30 pm

OK - they definitely work with Bosch 3-pin CDI boxes & should work with 6-pin CDI boxes (according to N H Speedo) but I don't have a car equipped with a 6-pin CDI to test them on.

Mick has a 10k tacho that was supplied by NH Speedo several years ago which works with a 3-pin but not a 6-pin CDI ...

- sorry about the long-winded explanation !

911_2.2T · Post by **911_2.2T** » Fri Jun 10, 2011 7:11 pm

If they are 3 pin they definitly do not work with 6 pin.
Did you both test them in your car?
(Early ones frequently need a ballast resitor to make them work up til around '70?)
Looking for a spare 6 pin myself.

davidppp · Post by **davidppp** » Fri Jun 10, 2011 8:34 pm

Hmmm.

North Hollywood do almost routinely modify them now: unless you are a real cheapskate ..and I am pretty sure they gairantee them to work with all flavours..

Kind regards
David

Lightweight_911 · Post by **Lightweight_911** » Fri Jun 10, 2011 11:12 pm

First one has been sold ...

Mick Cliff · Post by **Mick Cliff** » Sat Jun 11, 2011 6:02 am

911_2.2T wrote:If they are 3 pin they definitly do not work with 6 pin.
Did you both test them in your car?
(Early ones frequently need a ballast resitor to make them work up til around '70?)
Looking for a spare 6 pin myself.

I don't know to whom you are directing your question but.....
My 10k tacho works OK in my cars equippied with 3-pin CDI's but NOT in the car with the 6-pin CDI
Do you have more info regarding the resistor (spec/diagram) you mention?
Sorry to hijack your thread Andy

911_2.2T · Post by **911_2.2T** » Sat Jun 11, 2011 8:04 am

I had one off my tachs converted to a 10K tach, it was the 3 pin type and now that we decided to put a 3L engine in it, we couldn't reuse that tach and had a regular tach converted.to 10K and changed to be used with 6 pin. I'm not sure what the difference is but the VDO specialist assured me that if I would use the 3 pin on a 6 pin car it would not work and might even get damaged by doing so.

I also have a 69 tach that I tried to use in my 71 car, but it did not work. I had it tested and the tach was fine. The explenation I got was that it needed a ballast resiter that is on the pre 70 cars in the relay panel in the engine bay.

That is just about as far as my knowledge goes on this.........
Maybe someone else can explain some more about the why and how.

I would be interested to know if there is a way to have the tach work for both 3 and 6 pin boxes.