Quote:
Originally Posted by boyt911sc
rnln,
NO!!!!The oil filter is never by-passed as far as the SC/Carrera configuration is concerned. When the engine is cold, the oil is circulated within the engine until the engine thermostat opens up and send the 'warm' oil to the auxiliary thermostat. Auxiliary thermostat does not come into play until around 180°F (+/- 5°). Some portion of the oil is diverted to the auxiliary cooler, the tube (cooler) is filled and stop its travel at the return-valve (aux. thermostat) and the rest of the oil is by-passed at the aux. thermostat going straight to the oil filter and down inside the oil tank. This cycle will continue until.........the oil temp. of about 180°F is reached.
At this point (oil temp. @ 180°F), the by-pass valve starts to close and the return-valve opens too. Remember that the by-pass valve and return-valve are configured on a single cylindrical slide valve. It is designed in such a way that the amount of closing/opening is always equal to 100% at anytime during its operation. The slide valve operation (aux. thermostat) is temperature dependent.
For example as the engine oil is heated:
By-pass valve fully open........Return-valve fully closed.
By-pass valve 90% open.......Return-valve is 10% open (90% closed).
By-pass valve 50% open.......Return-valve is 50% open (50% closed).
By-pass valve 40% open.......Return-valve is 60% open (40% closed).
In summary, all the engine oil circulated to the auxiliary thermostat passes thru the oil filter cold or warm. HTH.
Tony
|
It's always possible for some oil to bypass the oil filter due to it's internal spring structure, if there is enough pressure on the unfiltered side the spring compresses allowing oil to by pass the filter element. Under what conditions this applies I do not know, if you measure the strength of the spring you would know, it is a fairly stiff spring.
993s filter on both the scavenge and pressure sides, others only on the scavenge side