Originally Posted By: Ded Mazai
Originally Posted By: ZeeOSix
You can't really compare "flow area" between a full synthetic and a cellulose media. Full synthetic filters 3 dimensionally while cellulose filters in 2 dimensionally. This is the reason full synthetic media flows better and still filters a high percentage of particles. Go do some research on the 'net about synthetic filter media and you'll see that kind of information.
What do you mean we can't compare the flow? Everything we need to know is a delta P across one filter and the other filter. I really don't care how the oil flows inside the filter and inside the media. I only care how easily it flows (with minimal delta P).
As Garak already mentioned ... I said flow area. Full synthetic media flows more volume per area than cellulose.
Originally Posted By: Ded Mazai
Also I know that you always like to refer that a positive displacement pump supplies the same amount of oil regardless of the back pressure. That would be true if you didn't have any losses (internal leakages) in the pump. In fact the higher the backpressure the higher the loss and the lower the pressure at the bearings and the valve hydraulic lifters.
Only time an oil pump would be effected by the flow restrictiveness of an oil filter in terms of pump internal leakage is if the oil pump was basically shot and worn out. You do realize than in a typical oiling system the engine itself is 15 times more flow restrictive than an oil filter. Meaning typically an engine will produce about 75 PSI of back pressure (delta-p) while the oil filter will produce about 5 PSI of back pressure (delta-p).
Even if the oil filter was completely clogged and provided say 12 PSI of back pressure (it's bypass valve opening pressure), an oil pump in good shape should be able to still provide nearly the same volume per engine RPM curve.
Originally Posted By: Ded Mazai
And when the oil is cold the pump bypass valve opens letting the oil back to the sump. The pump is not pumping if the valve is open.
Well, not exactly ... because when the oil pump goes into pressure relief it's only pumping the excess oil back to the sump. In fact, then the oil pump is in pressure relief mode, it's going to be supplying the maximum oil pressure possible to the resistive circuit attached to it's outlet side. That means for whatever the viscosity of the oil is at the time, that's the maximum volume that can be shoved through the resistive flow circuit. The circuit can't take any more volume, so the pump pressure shoots up and the pump has to shunt the excess volume back to the sump. Take the pressure relief valve out of the system and a PD pump in good condition would shoot the supply pressure up to over 300 PSI and probably blow the filter's can apart.
Originally Posted By: Ded Mazai
This is what happened to the topic starter. You cannot convince me that it is not the filter's fault without the delta P numbers.
I think what happened in the OP's case is the ADBV was leaking while the engine was off, making the engine tick on start-up. Unless I missed it, he never said the engine was ticking all the time, only upon cold start-up. Some engines are very sensitive to the ADBV leaking and the oil galleries draining out. Personally, I've never had an engine like this ... not even after an oil change where I let the oil drain from the engine all night with the filter removed.