Maybe this ties into the required effort- blow-by.  Carbon gets past the
rings and fouls the oil.  Higher effort would create more blow-by.

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Harry Hoffman
Sent: Friday, October 25, 2013 8:58 AM
To: vanagon@GERRY.VANAGON.COM
Subject: oil change interval for non-wbx setups

Hi All,

So, Dennis and I were having a interesting chat at Blue Rocks about
different power plants and when to change oil.

He suggested, and please correct me if I'm wrong Dennis, that oil change
should be based on a few different criteria: miles driven, gas consumed,
time since last change, and effort needed for the engine to move the
vehicle.

The last had me thinking about it since our conversation. My oil is
always super dirty at the 3k point. I'm running a bostig setup and
hadn't really thought about the reasons why until we talked. Since the
engine needs to operate at a higher rpm range there's a greater level of
heat generate and more "effort" required then say if that zetec was
still in a focus.

Are other people changing their oil at a earlier interval? Has anyone
done a comparison to the amount of money spent on oil (the bostig folks
recommend full synthetic) if you are changing it more frequently vs the
cost of letting it go longer and replacing the engine?

Also, blue rocks was our inaugural campout. The wife, myself, and our
two little girls (ages 3 and 1). The rain was a bummer but overall it
was very successful.

Looking forward to many years of it until they no longer want to hang
out with dad, lol.

Cheers,
Harry