I'm curious what kind of impact the brand of oil and additives that one uses has on the plastic timing chain guides?
Would some oils chemically create a more brittle guide? Will some oils do a better job of keeping the guides composition like new? Is that part of the dynamics that increase or decrease the life span of the guides?
is it more about heat?
possibly other rubber components as well like seals and older hoses?
Oils have definitely changed over the last 34 years.

 

I’ve used steel guides for last decade. Kinda took last one too far. Steel guide was plastic coated. I was having chain slap. Once pulled the plastic coating was fracturing off of steel. Had significant chain “stretch.”

as for oil, I use Rotella T6 just because of zinc content and price is better than boutique oils and synthetic.

with the heating and cooling cycles plastic is going to crap the bed sooner or later. But even with steel chain stretch is a thing. Though it’s not truly stretching links it’s wearing where pins go through links. Thus elongating chain. So even “extending” life of plastic guides is only one component of a wearable set of parts.

 

The heat may make the guide brittle, but it’s the chain that takes them out in the long run. I don’t see oil brand or type being that much of a factor in their demise.

 

That brings other problems I think.