Rotten Rubber

[JJDraper]

I have noticed that the quality of some rubber engine parts are not what they used to be. For instance, cam box bungs, old and new. I attach a couple of pictures of one I took out recently, compared to a new one. Bear in mind that the engine had only done around 30K miles in four years, with top quality oils (Millers Classic) and no additional additives. What is going on here? The parts came from a reputable dealer. The replacement in the picture has suffered a similar fate after 5k miles, nearly popping out into the cam chain tunnel....

Is this uncommon or am I doing something wrong?!

Jeremy

[gordonlund]

Who did yo get these from? I have never seen anything like that in 26 years of running Elans. They normally just go hard but never swell. Yours must have been the wrong rubber mix. Nitrile rubber is usually oil resistant.

Gordon Lund

[Emma-Knight]

...as far as I know, some Miller oils for classic engines have a built in leak stop - with other words make rubber softer and swell a little. At least I think I've read that.

Anna