OIL IN THE MECHANICAL TACHO

[914-6]

Hi, has any one else experienced oil being wicked up the tacho drive and into the gauge?
I have removed the oil pump outer plate, completely dismantled and re assembled the tacho drive with a new rubber seal (not once but twice) and still the oil is screwed up into the tacho head.
that's twice I've had to remove the gauge and strip/clean.
any ideas?

thanks
Ian

[Mike Smith]

Good Morning Ian,

I assume that we are talking 356 ?

Is the Oil Seal in the correct way around
There is also an essential Shim at the Taco drive end of the cable
The cable will also need washing through, once this has happened

[Winston Teague]

No 356 specific experience but this happened on my Frazer Nash. The cable had been made the 'wrong way around'. The spiral wind of the inner cable was such that it tended to draw the oil along to the gauge. This oil, may, however have been the result of wear in the oil pump housing/tacho output. Unscientifically i changed cable and fettled oil pump at the same time so may never know what the fix was, or how long it will last!
W

[Ignatzcatz]

This is absolutely gospel. I was in hospital getting some new bits fitted, I can't remember exactly what, when I received a visit from my 356B T5 owning friend who always is rather smartly dressed. On this occasion he was wearing beige cavalry twill sort of trousers, very smart but his were darkly spotted all down the front. So I asked Mike what the hell have you been up to? He was understandably shocked to be out in public in such a state and swiftly left me my grapes then left me.
After visiting Andy Prill who always took care of his car it was found that the oily sprinkling on his trousers had come from the mechanical tach cable winding oil along it's length from the engine up to the dash. So the moral of this true story is get an electronic tach, oh and Mrs. Mike threw the trousers away and Mr. Mike got a new tach drive cable fitted.

[mycar]

I've recently developed the symptoms.

Again !

It was back in 2012 I first experienced the slippy heel syndrome, so by my reckoning a tach seal lasts 6 years, Prill or no Prill.

viewtopic.php?f=3&t=39247&

I'm interested to know how you flush a tach cable through.

[914-6]

Thanks Mike for your swift reply

Maybe I should have contacted you directly as I'm aware that you have "the knowledge", however I feel it's important to aire these problems so that the masses can gleam the knowledge from the timeserved gurus.

I believe I have the new seal in the correct way, ie: to throw any oil seepage back into the oil pump drive.

I forgot to mention the cable is new, having had this problem before and assuming that the cable was to blame.

You mention that there is an essential shim in the tacho---please elaborate, is this inside the drive at the oil pump end or at the tacho head end(in the dash).

I have stripped the unit out of the drive (oil pump) cleaned and reassembled in the correct way according to "PET".

I'm not wanting to fit an electric tacho as I want to keep the car as mechanically correct as possible.

Many Thanks

Ian

[Mike Smith]

There is also an essential Shim at the Taco drive end of the cable

Sorry I did not mean to shout at you so loudly

It is shown in all the Porsche Parts Books - I took it from Jan 1960 356B Book
Illustration 1/6 - Item 55 - Part No. 369 05 707 (Do I need to say that it is In Stock at PRS)

Porsche call it a Washer but it actually a shim
They call the Oil Seal a Gasket - that is item 55

Ian - Next question - where did you buy the Oil Seals ?

[914-6]

Thanks Mike.
I've been in touch with PRS

Ian

[Mike Smith]

Lets hope that that is the problem- otherwise I am devoid of ideas