Buna N is probably the most common rubber used for a lot of applications but there are a few limitations. 70% of what you'll probably need an o ring for can be done with Buna N so having the o ring kit is a good thing if you need static seals. If the o ring is being used in a dynamic application, you'll have to find a replacement manufactured o ring. The Superglue joint won't last in a dynamic application.
If you haven't seen an o ring compatibility chart, you should be aware of it. I reference them all the time.
follow this link to see why.
All O Rings compatibility chart
As an example= an o ring choice for Engine Oil is not a good o ring for eythelene glycol and this might explain why there's 2 o rings on the bottom of the cylinder sleeve in the cylinder block and yet, the gasket sets most have bought aftermarket have the o rings for the liners and the top o ring is silicone based (red) and the bottom o rings are something else (black) but there's not 2 separate bags of o rings to suggest a top and bottom o ring for the lower o rings. Leaves me with questions . ?????
