which tach ?

[Jeffrey Vogel]

I am starting some work on my 356 SC, seems to have an "wrong tachometer" according to B Johnson's book " a restorer's guide to Authenticity , by body VIN it should have electric tach but it's a mechanical one, and while it is a 6k unit the green area is 2,500-5,000 rpm and the red is 5500-6,000 ? my understanding is that 6,000 units were from C models with 5,000 to 5,500 red areas and SC had 7,000 units with red from 5,500 to 6,000. So is this a Franken tachometer or some unknown variant from Porsche , possible a S90 unit although green area isn't a match there either

[Ron LaDow]

I am starting some work on my 356 SC, seems to have an "wrong tachometer" according to B Johnson's book " a restorer's guide to Authenticity , by body VIN it should have electric tach but it's a mechanical one, [...]

Extremely doubtful that anyone fitted a mechanical tach to a car originally fitted with an electric tach. Check the routing of the tach drive cable and imagine trying to fit one of those without taking the car apart.

[Thomas Sottile]

Some of the early sc tach were mechanical tachs mine was one my 1964 showed a 63 date of production.

[Dick Weiss]

The 'C' tach (mechanical or electric) has the red zone starting @ 5200 RPM; The mechanical Super tach starts @ 5000, and the mechanical SC tach starts @ 5500.
The electric SC tach would have the 7000 max. revs.
I may be corrected if if not.

[Dan Macdonald]

My understanding is that the 1965 "model" C's had electronic tachs the '64 models had mechanical units.
That doesn't necessarily mean that the '65's were built in 1965, they could have been built in late '64.
For instance my 1965 model C has an electronic tach but was built in 1964. (That's in accordance with it's COA.)

Maybe that's something Brett should hone in on in his upcoming book(?)

[Mike Wilson]

The info on the SC tachs in Brett's book is incorrect. The highest read for a mechanical tach which was on the early C' and SC's is 6000 rpm.

Mike

[Jeffrey Vogel]

ah, so I probably have an original mechanical tachometer my SC despite it being only 6,000 rpm max

[Mike Wilson]

Correct...you can also check to see if there is a date stamp on the tach body.

Mike

[Al Cole]

What year is your car? When was it built?

[Jon Bunin]

I am starting some work on my 356 SC, seems to have an "wrong tachometer" according to B Johnson's book " a restorer's guide to Authenticity , by body VIN it should have electric tach but it's a mechanical one...

The factory 356C Supplement to the Catalogue of Spare Parts lists the tachometer changes by engine numbers, not chassis numbers.
This was because the engines' mechanical tachometer drives were deleted when the electronic tachometers were introduced.

If you know the original engine number of your car...

[Daryl Bertram]

A similar thread in Jan 2015 covered this topic as well. I've dragged the pic of our mechanical SC tach in '64 SC 127141 from that thread to here. It is 5500 to 6000 RPM red line. Kudos to the forum manager for adding the "drag and drop" feature for pics; super easy.

[Mike Wilson]

Definitive info, Jon.

Mike

[Greg Bryan]

Late '64 model year C and SC had electric tachs - it was a running change. My 64 SC Cab built in June '64 to the best of my knowledge (160595) has and always has had an electric tach with a 7000rpm max on dial - it has the added wire in the wire harness for the tach.
Added by edit - Jon's reference above states the electric tach started at engine 820997 - my engine number is 821067, so the change must have been in the May/June '64 timeframe.
Many of these late 64s were registered as 65 model years (including mine) to add to the confusion.

[Geoff Fleming]

My early SC, ( 215961), had the mechanical tach.

[Harlan Halsey]

My 63 SC has the mechanical tach like the one in the picture above-no surprise there. At the end of 356 production, Porsche went to electric tachs. The last one had only a small solid red band from 6000 to 6200-no red stripes.

BTW while the 911-912 tach is larger in face diameter, precluding its use in a 356, the internal mechanism is 356 size. It is possible to put a 12 v. 912 tach mechanism in a 356 housing. However rather than destroying two tachs it turned out to be only $100 more to have PA Speedo make the tach I wanted from scratch.(About $400) And I still have the two other ones.