Originally Posted By: wemay
Gold Plated! That must've been expensive.
Gold Plated! That must've been expensive.
Last edited:
Varnish: Friend or Foe?
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Originally Posted By: 285south
That's exactly what my dipstick looked like.
That's exactly what my dipstick looked like.
That is exactly what our Crown Vics look like too after 125-200k of bulk Castrol 5w20 OCI's at 5-6k intervals.
Usually start seeing consumption at 125-150k. By 200k you really gotta keep an eye on the dipstick.
Usually start seeing consumption at 125-150k. By 200k you really gotta keep an eye on the dipstick.
The second paper posted is particularly interesting.
"The authors report, for the first time, a comprehensive chemical and mechanical characterisation of antiwear films prepared from a fully formulated oil that is commercially available."
"Ca phosphates, ZnS and MoS2 are the main P and S species formed, contrary to previous studies involving only ZDDPs, whereby Zn phosphates are the dominant species."
"The implications of this study are that ZDDP does not
act fully as an antiwear agent in FF oil (in the form of Zn
phosphate), and possibly only facilitates the initialisation
of film formation. Once the onset of film formation occurs,
a ZnS and Ca phosphate film grow based on availability of
cations present and in agreement with the chemical
hardness predictions."
All the different additives form the film.
Originally Posted By: MolaKule
Here is a QOD from '04 that might help:
Lacquer and Varnish
If varnish is fuel derived, what fuel component causes it? Is this fuel component absent in diesel or is it due to different conditions inside the engine?
MolaKule
Staff member
Quote:
If varnish is fuel derived, what fuel component causes it? Is this fuel component absent in diesel or is it due to different conditions inside the engine?
It is due to two things:
1) The hydrocarbon makeup of each fuel,
2) the respective temperatures involved in combustion.
If varnish is fuel derived, what fuel component causes it? Is this fuel component absent in diesel or is it due to different conditions inside the engine?
It is due to two things:
1) The hydrocarbon makeup of each fuel,
2) the respective temperatures involved in combustion.
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Originally Posted By: camrydriver111
If varnish is fuel derived, what fuel component causes it? Is this fuel component absent in diesel or is it due to different conditions inside the engine?
In the crankcase, you have blowby gasses, which contain some higjly reactive things like NOx, Partially reacted hydrocarbons, CO, etc.
All of which attack the oil, and it's antioxidant ability.
Eventually, molecules are formed that are polar, have limited solubility in oil (more soluble when hot), and being polar have an affinity for metal surfaces, and cooler ones at that.
They start to plate out, and attract their friends.
Varnishes final settling place isn't usually where it's forming, just where it becomes insoluble.
If varnish is fuel derived, what fuel component causes it? Is this fuel component absent in diesel or is it due to different conditions inside the engine?
In the crankcase, you have blowby gasses, which contain some higjly reactive things like NOx, Partially reacted hydrocarbons, CO, etc.
All of which attack the oil, and it's antioxidant ability.
Eventually, molecules are formed that are polar, have limited solubility in oil (more soluble when hot), and being polar have an affinity for metal surfaces, and cooler ones at that.
They start to plate out, and attract their friends.
Varnishes final settling place isn't usually where it's forming, just where it becomes insoluble.
What is the best way to combat Varnish? High detergent oils? Shorter OCI?
Originally Posted By: MolaKule
Quote:
If varnish is fuel derived, what fuel component causes it? Is this fuel component absent in diesel or is it due to different conditions inside the engine?
It is due to two things:
1) The hydrocarbon makeup of each fuel,
2) the respective temperatures involved in combustion.
Originally Posted By: MolaKule
Quote:
If varnish is fuel derived, what fuel component causes it? Is this fuel component absent in diesel or is it due to different conditions inside the engine?
It is due to two things:
1) The hydrocarbon makeup of each fuel,
2) the respective temperatures involved in combustion.
The short answer would be shorter OCIs, or higher quality oil.
I don't see how that nice golden coating could be a problem. When I removed the oil pan on the t/a there was a thin layer of very thick oil. I assume that was real sludge.
.
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Originally Posted By: ryanm8
What is the best way to combat Varnish? High detergent oils? Shorter OCI?
Originally Posted By: MolaKule
Quote:
If varnish is fuel derived, what fuel component causes it? Is this fuel component absent in diesel or is it due to different conditions inside the engine?
It is due to two things:
1) The hydrocarbon makeup of each fuel,
2) the respective temperatures involved in combustion.
My engines never have varnish. M1 is the why, even at 10K OCIs.
What is the best way to combat Varnish? High detergent oils? Shorter OCI?
Originally Posted By: MolaKule
Quote:
If varnish is fuel derived, what fuel component causes it? Is this fuel component absent in diesel or is it due to different conditions inside the engine?
It is due to two things:
1) The hydrocarbon makeup of each fuel,
2) the respective temperatures involved in combustion.
My engines never have varnish. M1 is the why, even at 10K OCIs.
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