Triple seals: Viton

Wow, no more heating. What a wonderful idea.

Here is the link. I think I will buy a bunch.

Partnumber 137249VITON

Clutch Parts for Ferrari 355 - Superformance

 

This is a very common problem with the oem triple seals.
Good to know there is another option.
Thanks for posting.

 

and at £6.95 I will be ordering some

Spigot Shaft Sealing Ring- Viton
Alternative type sealing ring in high temperature Viton
3 Required per car
(355: 2.7 Motronic, 5.2 Motronic)
137249VITON

 

NICE FIND!

Thanks for sharing the info!

 

Anything O ring I use these guys. Good chance you will get their product a few levels down the chain under a different name


AMES INDUSTRIAL RUBBER AND PLASTIC O-RINGS

 

Thanks for the tip, Frank.

Thanks for the link, Tim.

 

I did nit think it was obvious so could someone please post the number of and part numbers for these thanks.

 

137249VITON It's down under the "Spigot Shaft" section.

 

Ive used Viton gaskets and Viton rubber o rings on many applications in my carreer. I have used it on 99% pure acid. Its a highly rated chemical resistant material.

 

Viton is excellent material for "static" O-Rings but the question is how it will withstand rubbing (rotation) when used for triple seals.

 

That would be my initial question, without any other cursory knowledge of the setup/materials. Does anyone know the material/trade name of the OEM seals?

 

If I recall correctly ... at least a while back .... Viton material was used for valve guide seals on Porsche ... so the material should be able to handle some friction ....

 

Good point, Viton is also used by some manufacturers in rotary shaft seals (like, for example, the crankshaft seal which withstands rubbing at high speed rotation). However, in the case of rotary shaft seals, a number of additives is used in the elastomer compound (including fillers) to give it required properties like low friction coefficient. I presume that the Viton triple seals have similar formulation and are not just plain Viton as used in the static O-rings. The relative rotational speed at the triple seals is up to about 5000 rpm in 1st gear, 3500 rpm in 2nd etc.

Another point is that the original seals (rings) are compressed into the outer sleeve to which they probably remain static and the inner shaft, i.e. its grooves, rotate against the rings with just, I think, lightly touching them. In the case of Viton rings, it appears that they will be compressed between the inner shaft grooves and the outer sleeve. They may rub against either of the two. If there is always sufficient oil around the seals, there should be no problem. But is there always generous lubrication at the triple seals location?

 

Enough such that it leaks if not sealed properly. So there is always some lubrication.

 

On the OEM parts I found there is no contact of the inside diameter of the triple seal and the minor diameter of the groove of the shaft - about 0.5mm diameter clearance!

I would post a picture of the drawing I have but I cant seem to upload anything anymore.

 

I have used Viton in my past life when I worked on fuel delivery systems for an OEM. Viton is a really great material and as others have said, if very chemical resistance. It also maintains it flexibility in temperature extremes and has less swelling than other materials.

In terms of it's applicability to rotational applications, it has more to do with the gland/groove/shaft dimensions. So if the seals are made specifically for the application (dimensions), then it should live in that type of an environment.

 

That is correct. The sealing, with a light contact, is at the sides of the grooves in the shaft to the sides of the sealing rings.

 

On all the four shafts that we have, we found that there is no contact of the seals on the sides. All of the groove widths are within 50 microns of each other and the seals are about the same and there is approx 50-100 microns side clearance. The lack of compressive nature of the OEM PTFE type seal means that it would not displace anywhere near like a elastomer seal when pushed into the input shaft. The whole setup seems to be acting like a labyrinth seal.

Its certainly interesting why Ferrari did it like this.

 

I had the same thoughts, more like a labyrinth seal. Why done like this, I think it is because there is no continuous lubrication at the point as it is well above the transmission oil level and far out of the transmission case. Looks like it depends only on some oil splashes or mist which are practically non existent at low speeds, especially when the transmission is cold.
Image Unavailable, Please Login

 

Picture showing cross sectional view and just the one seal on the far right groove.


http://www.hillengineering.co.uk/catalog/images/ph/1.JPG

 

Split rings made of lead-bronze would probably work fairly well as triple seals.