What is the dumbest method for adjusting valves on a 4-cylinder diesel engine?
2 Answers
First, take a 4-cylinder engine with a firing order of 1-3-4-2 as an example. When cylinder one is at the top dead center of compression, valves 1-2-3-6 can be adjusted. When cylinder four is at the top dead center of compression, valves 4-5-7-8 can be adjusted. Then, rotate the crankshaft 360 degrees clockwise to position the piston of cylinder four at the top dead center of the compression stroke. Here are some precautions regarding valve adjustment for diesel engines: 1. Note one: Never overlook the issue of valve clearance. If the valve clearance is too small, it will lead to a decrease in engine power and may even cause the valves to burn out. 2. Note two: Excessive clearance is also not allowed, as it will not only accelerate the wear of components but also affect the intake and exhaust conditions of the cylinders. Therefore, when abnormal clearance is detected, it must be addressed promptly.
My dumbest valve adjustment attempt was diving in completely unprepared. On that four-cylinder diesel with the engine still hot, I just popped the hood, grabbed a wrench and started turning the adjusting screws. Entirely by ear – tighten when hearing tapping noises, stop when quiet. Didn't bother measuring clearance with feeler gauges or even checking specs. Lazy method for sure, quick but ineffective – ended up with valves either too tight or too loose. The engine ran with valve noise loud enough to sound like hammering sheet metal. Within days, fuel consumption skyrocketed and valves started burning or leaking. Learned later that proper clearance should be measured with tools, around 0.25mm being ideal. Such corner-cutting should only be emergency fixes, otherwise repair costs double for half the work. Better to just buy an affordable feeler gauge and adjust precisely – saves headaches in the long run.
