Quote:
Originally Posted by just_me
Would be to understand the oil flow and pressure readings.
It has to be a case of marginal flow. The question is why?
All swapping does is say that the flow is marginal.
A worn motor will have low pressure and require a large flow to maintain even marginal pressure.
A worn oil pump or blocked passages will lower flow (high source impedance as noted above).
Not much to inspect on DOF - issues would be in how installed.
Grant
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Grant, this is going to bounce back and forth probably forever, but let's look at what we know:
- The car had a DOF installed and developed problems that multiple shops seem to have had a hard time tracking down.
- The OP was apparently the first person to think of disconnecting the DOF, and when he did, the problems stopped
- The OP installed a different manufacture oil feed IMS setup that sourced its oil from a different place in the engine.
- Problems do not reoccur.
Whether anyone likes it or not, in the case of this particular vehicle, an issue resulted from pulling oil pressure out of the cylinder head. Not taking the oil from that source appears to have ended the problem, and drawing oil from elsewhere does not cause the same issues. Perhaps the car has lower than normal oil pressure, but it is not coding or showing other signs of that problem's existence. Implying that the OP should be taking the engine apart to R&D the where's and why for's is a bit much. The OP solved his customer's problems and sent him on his way; that is what shops do, they are not out here to resolve aftermarket product issues for the manufacturer.
These engines are known for having marginal oil flow in the valve train galleys. Noise from the valve train, VarioCam problems, and premature lifter or cam wear are common documented problems that have never been traced to low oil pressure or volume flow from the OEM oil pump to my knowledge. And if you have ever seen the lifters out of one of these engines, many of the system oil passages are rather tiny to begin with compared to other engines. So there could have been multiple sources for what happened; varnish build up in the galleys, a small blockage by some stray factory sealant in the lifters, or God knows what. But the fact remains that disconnecting the DOF stopped the problem the customer was having. That does not imply the DOF is either the root or total cause of the problem; but it does imply it in some manner contributed to the issue.
So rather than becoming defensive, why don't we try and learn from the example and see if it reoccurs elsewhere. It could just be an isolated situation, but that does not mean that it did not happen.