How to adjust the valves of a 170 gasoline engine?
4 Answers
First, remove the spark plug and take off the pull cord starter. Take out the valve clearance measuring tool, then loosen the nuts on both the upper and lower rocker arms. Insert a 10mm feeler gauge beneath the rocker arm. Tighten the rocker arm nuts and remove the feeler gauge to complete the operation.
Adjusting the valve clearance on a 170 gasoline engine was something I did quite often in the workshop when I was younger. The most common issue with older engines is the clearance becoming too large, causing inaccurate valve opening and closing, resulting in a clattering noise and increased fuel consumption. When performing the operation, first park the car and let it cool down to avoid burning your hands. Then remove the valve cover to expose the rocker arms and valves. Use a wrench to slowly turn the engine crankshaft to align the first cylinder at top dead center. At this point, the valves are closed, and you can measure the clearance with a feeler gauge—typically, the standard is between 0.20 to 0.30 millimeters, but check the manual. The feeler gauge should fit snugly but still be able to slide through. If the clearance is off, loosen the adjustment screw, make the necessary adjustment, and then tighten it with a wrench. Repeat this process for the other valves, and after finishing, start the engine to ensure the sound is smooth. I usually check it every 10,000 kilometers to prevent oil leaks or part wear, avoiding major overhauls. Having worked on dozens of 170 engines, paying attention to small details can significantly extend their lifespan.
Last week, I adjusted the valve clearance of my 170 engine for the first time by myself. The engine noise was harsh and really annoying at the time. I checked the process online and bought a cheap feeler gauge set. After the engine cooled down, I lifted the hood and removed a few bolts to expose the valves. Turning the crankshaft was a bit tough, and it took me a long time to align the timing marks. When measuring the clearance, I found the exhaust valve had a gap as large as 0.4mm, so I quickly loosened the screw with a tool to adjust it to 0.25mm. My hands were shaking during the operation, afraid of damaging the parts, so I measured twice to confirm. After putting the cover back on and starting the engine, the noise reduced, and I finally breathed a sigh of relief. I recommend beginners to have a car-savvy friend by their side for guidance and to wear gloves to prevent scratches. Engine maintenance is a science; once you learn it step by step, it doesn’t seem so difficult.
Valve clearance is crucial; incorrect adjustment can lead to increased fuel consumption or excessive noise in a 170 engine. First, I must remind you to prioritize safety by parking and allowing the engine to cool. Locate and remove the valve cover, then rotate to the correct position. Use a feeler gauge to measure the clearance, which should be between 0.2 to 0.3mm. Adjust the screw to achieve the proper tightness, then reinstall the cover. Performing this simple task can prevent malfunctions and extend engine life.
