Hello, I have an 87 ford L8000 with the Brazilian Ford 7.8 diesel. It has developed a knock when it is revved up. It started about a month ago, after the truck was shut off and restarted it seemed to be gone. It originally started knocking suddenly. The next day after being run for about 20 minutes it was back. Since then it seems to come and go. Now it does it more regularly. Dropped pan and checked for any sign of bearing wear, oil was clean. Was wondering if this could be an injector fuel knock? About to install rebuilt injectors. Valves all in adjustment. Listen with stethoscope can't find where it's coming from. When listening with scope to engine, air compressor, water pump, pullies nothing stands out although injection pump is by far the nosiest Any ideas? If injectors don't solve it what next? Compression test? Pull head to check for bad valve? Any educated or uneducated guesses would help. Thanks Walt
If you can get it knocking while parked loosen injector lines one at a time. That might isolate it to a cylinder. Starting with buying parts can be expensive in the end. Those injectors are inexpensive to have tested.