Leaky cyl/head O-ring fix?

[Jordan]

Replacing the O-ring on the cylinder dowel on my 350 didn't stop it leaking for long.
I haven't tried one made of Viton or similar. Is that a likely fix?
The material seems softer than the original type, which seems to get too much crush by the look of it.

Jordan

[blaat!]

McMaster Carr has a very nice chart on O-ring materials. If you do a search on their website for "O rings" and click on the link at the top that says "General Properties for O Ring Materials" it will bring up a chart with eleven different materials.

[Jordan]

Thanks Blaat!

That's a good resource.
I was interested if Viton's relative softness compared to other materials could prevent it being crushed to destruction when installed.
The Ducati single design doesn't follow industry norm, which is to provide a square shaped groove or trough (as per Ducati V twins), which is slightly shallower than the thickness of the O-ring. This shape provides room for the O-ring to bulge into the corners when assembled, avoiding the tendency to breaking it.
I was wondering if a softer material let the O-ring survive the intense compression from the cone shaped space that the factory provided.
Otherwise, a visit to the milling machine might be in order (Gulp!). But I'd rather not change the original shape, if a change of O-ring material fixes it.
It's a fairly common problem I think, and thought someone might have some info?

Jordan