Get the car running to proper condition, requires the fuel system to be properly tuned, injection pump timing, new filters, new injectors, all glow plugs operating correctly, all air leaks fixed. Then start the valve adjustments, adjust run the car hard for a few hundred miles, adjust again....and continuing to adjust the valves to they hold clearance....then oil change time, keep changing the oil and driving the car hard....you have to get the carbon out....only way is by burning it and oil changes....these cars are so gunked up from not having regular changes it is amazing.....there is actually an oil pressure relief valve in the oil filter housing, when the filter clogs it opens and allows the oil unfiltered back into the engine....I changed my oil maybe 500 miles ago....I pulled the oil filter and there are carbon particles big enough to see with the eye stuck all over the filter....

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