64c tach help
 

Hello!

'64 356c with 912 engine.
Tach doesn't work.
356c and 912 wiring diagrams both show an electronic tach.
Tach in car has mechanical connection.
Do I have wrong tach?
Now what?
Replace tach? Modify tach?

Thanks!
BK

http://forums.pelicanparts.com/uploa...1414505525.jpg

912s had an electric tach. (Not an electronic tach.) 356s had a mechanical tach, although a 6v electric tach was available. Some 356C cars were sold with 12v electrical systems. Some Carrera models were 12v, and they may have used an electric tach in some cases. You have a few options: You can send your tach to someplace like North Hollywood Speedometer and Clock and have it converted, adding in the wire from the (-) side of the coil to the tach; you can find an appropriate electric tach; or you can replace the oil pump cover and the oil pump gear that drives the tach pinion. The 912 tach is not an option as it's considerably larger in diameter.

The Cap'n

Thanks capn. I forgot all about the 6v 12v issue. All other gauges work and the car is 12v. Will lift car and see exactly Where the cable goes.

The cable goes into the oil pump cover from the left side. You'll need the cover and gears from your old engine.

The Cap'n

I have a 12V 64C with the proper engine and the tach is mechanical. I believe you have the wrong tach for that engine. As mentioned above, NH speedometer or Palo Alto would help you on deciding which way to go.

OK I am really confused now.
Looks like I have the mechanical tach connection on the engine too.
I thought all 912s and 64Cs were electric?
Maybe this isn't a 912 engine?


http://forums.pelicanparts.com/uploa...1414607688.jpg

That configuration/picture looks just like my 64C with the mechanical tach cable coming out of the oil pump; not sure how the 912 engine looks like...

http://forums.pelicanparts.com/uploa...1414615789.jpg

This is a picture of a 912 oil pump cover, courtesy of e-bay. The entire 912 timing cover is just a little different than the 356C cover, as well. The 2 upper bolt holes on each side are larger, to allow for the motor mounts. Note the special nuts in this picture:

http://forums.pelicanparts.com/uploa...1414616127.jpg


I hope these clarify your understanding of the differences!

The Cap'n

Ditto for my 1964 SC coupe, if it were me I would get the original cable operated tach working. As far as I can tell ours is original and works fine.

Early 64C/SC cars had mechanical tachs. Mine was built in Oct 1963 and came with a mechanical tach. The only serious reason I see to convert to an electric tach would be if you want a full flow oil filter, then it is much easier and simpler to use the electric tach as modifying the oil pump cover is difficult. But Vic Skirmants now sells a new cover with outlet oil fitting that retains the mechanical tach drive.

Thanks for all the info guys.
Looks like i probably have an early 64C case.
It is unstamped so still not sure, but most of the signs point that way.

Havent figures out the tach issue. Too cold to mess around too long in garage!

The result does not look too bad count

I have a '64c (hardtop cab!) which has a 6v elec tach from a '65c (still have the mechanical tach). the '64 is wired (at least there were/are 2 wires going from under dash to engine compartment, unused). Connected the wires to tach, connected the other end wires, one to each side of ignition coil. (power/points) It works just fine. I had swapped '64 &'65 motors to do valve job on the '64, & '65 has no mech tach drive on the pump plate, hence tach swap. Swapped back motors but left tach as was/is.

-c-

One of the only differences between model year '64 and '65 cars is the '65 cars had electric tachs. Your face is for a mechanical tach.

6 volts was standard on pushrod cars. 12 volts was a relatively rare option.

Thanks guys.
Disconnected the cable from the back of the tach and it does not spin with the engine running.
I guess the next step is to remove from the engine and see what happens?
Its just been soooo cold!

FWIW that tach is for a 60hp B T6, not for a C. redline for a C starts at 5k. Both are mechanical type. If the cable isn't spinning at the gauge end with the engine running it may be time for a new cable.

Cold here in AZ too! low 80s... freeezing!

Finally got around to replacing the tach cable.
The old one was definitely broken.
Had to remove the shifter, but other than that, pulling the new cable was not too bad.
Until I connected to the tach and it still did not work!
Cable spins now, but the tach does not work.
So... just bought a new tach too!
One with the 5k rpm redline.
So now the tach works, but makes a low pitched whine.
Is there a way to lube it without taking it apart?
Maybe spray some wd-40 somewhere?

You need to pinpoint the noise. First, disconnect the tach and drive the car with the cable off. If the noise is still there, use some good quality lubricant like Tri-Flow. WD 40 is junk, and good for water displacement and squeaky belts. Then check the cable routing. Sharp bends are always an issue. If the noise is in the tach head, it really needs to be cleaned and serviced.

The Cap'n

FYI, the european 'C's had a mechanical tach; the american version had the electric.

The PET shows the electric tach to be "for subsequent installation", indicating that it was NOT standard original equipment. It even shows a block off assembly to be placed on the oil pump when converting.

The Cap'n