Re-visit of "Fuel in Oil"

[MaxACL]

This I posted in the same area here but after further considerations.... Others that might not view the Mobil 1 subject may be interested.

Bear with me as I know many knowledgle people have already said that Diesel in oil in really no concern, but this subject hits home:

This quote from elsewhere raises a question concerning massive amounts of oil in the crankcase:


CH-4 is a slightly older spec that also is supposed to deal with EPA-mandated emissions redesign, primarily the design of the piston. This is an extension of the first such controls from the early 90's.

The piston is redesigned to reduce blow-by and particulates that used to shoot out the stack. This is done by moving the ring land area, especially the Top Grove, much closer to the top of the piston, the crown land.

The Top Grove compression ring now sees much higher temps than it used to. As a result, a weaker oil can break down and create carbon/sludge/varnish deposits in the Top Grove.

Eventually, the Top Grove compression ring will stick and/or break. The combustion gasses can then venture lower and take out the other rings and oil control ring.

Also, if Top Grove fill is allowed to happen, the carbon and varnish act as an abrasive and quickly wear away the crosshatch pattern on the liner or cylinder wall. You then get massive oil consumption. I think Top Grove fill is set at around 14% max in controlled tests.

"A weaker oil can break down"

When the injectors went South on my DuraMax I drove for (perhaps) 500 to 1000 miles (un-knowingly) on diluted oil. Should I (we) worry about this?

Mike

PS: Again, I'm in the Big Desert and will be away from this forum for a week, perhaps less. My appoligies for starting something and leaving. :rolleyes:

[MaxACL]

On Edit...

massive amounts of FUEL in the crankcase:

[More Power]

As it was explained to me, part of meeting the more stringent emissions regs involved moving the top piston ring closer to the top of the piston. This reduces the amount of cylinder volume not exposed to the higher combustion temperatures - thereby reducing hydrocarbon emissions. The downside could be more stress and heat on the piston rings, but reality indicates it not to be a problem (diesel engines have been using the revised piston ring location for some years now).

CF, CG or CI oil should all be fine. However, synthetics of all stripes are generally more tolerant of high temps, and reduce lubrication related buildup better than a petroleum product. For example, pistons skirts and ring grooves in engines run with synthetic longterm are nearly spotless and are far cleaner than pistons removed from an engine run with petroleum oil.

MP