I was having a bit of a chat with a workshop in Sydney......was talking about fuel enrichment and he raised the issue of 10.2 type AFRs wrecking the oil by fuel contamination as according to him rich AFRs will lead into the fuel contaminating the oil. He claims that such engines in the long term when pulled down have damage to bearings and worn surfaces as a result of a loss of performance to the oil system.

1. Is there any proper evidence to support rich mixtures in rotors where fuel contaminates the oil?

2. Is there any proper evidence to show that fuel in the oil reduces the lubricity of the oil?

I was thinking about this more.......like when cold the AFRs go right down to choke the engine in keeping it running while cold. So even if you had say 12.1 type WOT AFRs wouldnt the act of starting a cold engine contaminate the oil with fuel anyway???? i.e. Isnt this problem therefore inescapable regardless????

This workshop is pretty well known and I spoke to "the man" who does all the tuning and stuff at the shop. He says hes tested Cosmo's factory and they run like 10.7 / 10.8 at WOT and according to him thats way too rich.

 

What he says sounds likely. As that's the same reason why diesel engines should have there oil changed more regular than a petrol engined car.

rgds