Tach cable question

[Christopher King]

I am hoping for some help with a tach problem I have encountered.

I am coming off a fresh rebuild, and had my engine rebuilt as part of the process. A new tach cable insert was installed. I drove the car for about 20 miles, and it seemed to work just fine. After about 15 miles I noticed some dark "oil" like substance dripping from under the dash. Shortly after that I noticed the tach was acting funny. It would stick at a number, and then peg all the way around. When you turned the car off it would slowly wind back down. I took a look at the back of the tach and saw some of the oily liquid. I removed the cable from the back of tach, and roughly a tablespoon of the dark oil spilled out of the inside of the cable. I checked the engine end of the cable, and it looks like the oil screen/filter is installed in that end.

My questions are:
1. is it normal for oil to pushed up into the cable for lubricating purposes? If so, how much. I got roughly a 1/4 cup of oil out of the cable into a ziplock bag when I drove it 20-30 miles without it being hooked up to the tach.
2. what does the oil filter look like? I assume it is a flat black ring in the oil pump, where the cable connects.
3. Is there a filter/seal on the tach side of the cable as well?
4. where can you buy a new filter? I checked all the normal parts shops online, and I don't see any one carries them.
5. any other suggestions on what the problem could be or how to fix it?

Much thanks in advance.

[Mike Wilson]

I'm not aware of a filter in/for the tach cable. On the engine end of the cable there is a seal and thin washer. Oil shouldn't be traveling from the engine to the tach. It will need to be cleaned.

Mike

[Christopher King]

Thanks for the response Mike. Is the seal and washer two separate components, or the same? I think what I can see is the flat black washer. Not sure if there is a separate seal behind that. Any ideas on where to purchase a new seal if needed?

[Mike Wilson]

The black seal you see is the only one. Hopefullybsomeone can post a pic of the assembly. It sounds like you are missing the metal washer. Stoddard carries the parts you need and my guess is that there is a diagram on their website.

Mike

[Mike Wilson]

Tach cable oil drive seal: 539-07-117
Tach cable shim washer: 369-05-707

Mike

[David Green]

i drilled a very small hole in the ferrule at the engine drive end of the cable so that if it ever leaks the oil will drip out there and not get screw-pumped up the cable and ruin the tach.
David

[Dick Weiss]

When replacing the tach cable insert, make sure the seal is also replaced along w/the little shim which lightly squeezes the protruding seal when snugging up the ring nut. Never drill a hole to allow an oil leak.
OH--make sure the seal's lip is pointed toward the casting and NOT outward!

[Christopher King]

Thank you all. I will order a new seal/shim and see if that helps. I appreciate all the responses.

[Dick Weiss]

By the way, the seal's lip runs on the tach-drive output shaft; Not on the cable's end.

[Christopher King]

Just closing the loop on this discussion. I replaced (added) the metal washer, and the result was immediate. No more oil being pushed up the tach cable. Thank you all for your help.

[Mike Wilson]

Congrats on solving the problem.

Mike