The O-rings sold for use on fuel injectors are made of Viton, the trade name of a fluoroelastomer patented by Du Pont.

According to Wikipedia:

"Viton fluoroelastomers are categorized under the ASTM D1418 and ISO 1629 designation of FKM. This class of elastomers is a family comprising copolymers of hexafluoropropylene (HFP) and vinylidene fluoride (VDF or VF2), terpolymers of tetrafluoroethylene (TFE), vinylidene fluoride (VDF) and hexafluoropropylene (HFP) as well as perfluoromethylvinylether (PMVE) containing specialties. The fluorine content of the most common Viton grades varies between 66 and 70%."

According to the Du Pont Viton website:

"In the automotive field, the latest generation of Viton® has established a new performance standard for today’s advanced fuel and engine systems. Viton® provides improved system durability in extreme temperatures for fuels, oils, transmission fluids and acid condensates. In tough oil and gas down-hole applications, Viton® can help extend maintenance intervals and help protect against seal failure."

A year ago, I installed X300 fuel injectors in our '93 XJ40. During that time, I completed the cleaning of the original XJ40 injectors (see links to photos of my cleaning procedure in a previous post in this thread). Our son is home with the XJ40 for Spring Break, so yesterday I swapped the original injectors back into the car, removing the X300 injectors, which I had installed with a wipe of engine oil on the O-rings per the Jag manual instructions. The O-rings look as-new, with no discernible deterioration or softening.

Cheers!

Don

 

I'm about to replace the cover gaskets on my brothers '03 XJ8. Which spark plugs are perfered or work well? The car has 116,000 on the clock and I don't think they have ever been replaced.

 

Stock NGK iridiums work perfectly in my xj8 and xjr

I tried going one step colder Denso U groove in my xjr, but that was too cold. Probably because I'm running water injection.

 

Finished replacing my cover gaskets last night. Was a labor of love... not that it's highly complicated, but clearly someone messed with it before and had to delicately scrape off former 'shortcut job' i.e. a lot of stuck "silicone"... Used the Lincoln LS gasket kit (Advanced Auto Parts, $45 after discount) and fit perfectly my AJ27. Tighten bolts at correct torque. Also changed plugs and used NGK iridiums. Running great.


Cheers

 

Somewhere in the huge fuel injection damper thread started by Maxwdg is a discussion of viton. The gist of it is that there are different grades of viton, and that Dupont recommends silicone lube for installation.

Petroleum jelly is still ummm ... petroleum.