The 928 engine design is very good in
many respects except one - Oiling. The stock engines suffer from the
dreaded 2/6 failure. This happens when the oil pickup is no longer
submerged, for example long sweeping left hand turns taken at high speed.
The G force causes the oil to be pushed back up the oil passages into the
passenger side cylinder head leaving the oil level below the oil pickup.
The main reason this happens is that the original sump baffle was not
effective. Then there is the issue where the drivers side oil drains are that they
are aimed directly at the spinning counterweights, causing severe windage
inside the crankcase. (oil particles suspended in air) The 928 engine also
does not have a very good oil separator so that air ingested into the intake
from the crankcase usually has a high volume of oil in it. I decided to
address both issues in my engine. I incorporated a very comprehensive
crankcase baffle, windage tray, as well as a crank scraper. I also decided to
improve on the factory oil separator.
Here is a pic of the crank scraper:
I decided to go with the version that
contained teflon insets. The reason for this was that I needed to trim
the scrapers due to the differences between the stock rods and crankshaft
counterweights. I figured that trimming 4 separate pieces of teflon
would be easier than trimming one continuous piece of steel. (keep in
mind there are 8 counterweights and 8 rods)
One of the problems with the 928 block
is that there are 4 oil drains from the drivers side cylinder head that drain
right onto the spinning counterweights for the crankshaft creating a huge
Here is a pic of one of the cylinder
Here is a pic of the oil drain
This collection of parts is mounted on the drivers side of
the block. The 4 L shaped pieces are the deflectors that keep the oil
draining from the drivers side cylinder head from draining directly onto the
spinning counterweights. Notice that the oil deflector is multi layered
steel, and is notched for my connecting rods.
Here is a picture of the oil pan and the
GTS baffle which I installed in the last version:
The problem with the factory baffle is
that it does nothing to keep the oil around the pickup during high G left hand
sweepers. Its also too low. The oil level is actually above the baffle.
Here is a picture of the elevated
baffle. This is designed to work with the crank scraper and windage
In the above pictures I outlined parts that help
diminish the amount of oil suspended in the air. I also decided to
minimize ingestion of oil suspended in the air into the intake.
Here is a pic of the factory oil
separator..... if you can call it that... its really simple.
Here is a pic of the modification for
the oil separator. Above the visible grate is a wad of course
steel wool that will separate oil from the air as it passes thru to the
M48 Pro Suspension