How to Align the Timing Belt on Chang'an 474 Engine?
3 Answers
Chang'an 474 engine timing belt alignment method: 1. Align the crankshaft according to the marks on the crankshaft timing pulley, generally requiring the No. 1 cylinder piston to be at the top dead center position; 2. Install the camshaft timing pulley and align the marks on the camshaft. For dual camshafts, align both camshaft positions separately; 3. Install the timing belt/chain properly. Below is an introduction to the timing belt of the Chang'an 474 engine: 1. The camshaft pulley of the 474 engine has two grooves inside the inner diameter, fitting onto a small protrusion on the camshaft. Generally, in factory settings, the E point on the camshaft pulley inner diameter is engaged with the camshaft, so the timing should correspond to the E point. 2. Engine mechanical timing refers to the relationship between the valves and the piston. For example, at the compression top dead center, the piston should be at the top of its stroke, and the intake and exhaust valves should be closed. If the valves or piston are not in the correct position at this time, it indicates an error in the engine mechanical timing. When checking the mechanical timing of certain engine models, a dial indicator is required to confirm the piston top dead center.
I've worked on quite a few Chang'an 474 engines, and timing belt alignment is not something to take lightly. First, you need to rotate the engine to position the first cylinder at top dead center, making it easier to align the camshaft and crankshaft marks. Then remove the old belt and clean any oil residue from the gears to prevent slippage. When aligning, pay attention to the marks on the belt—they must perfectly match the zero mark on the camshaft gear and the corresponding point on the crankshaft gear. Use your hands or a tool to gently tension the belt, ensuring it's not loose. After that, rotate the engine a few turns and double-check if the marks are still aligned. If not, you'll have to start over. This is quite a technical task; getting it wrong could potentially ruin the engine. I once had a close call myself, so I recommend beginners not attempt this as a DIY project. It's safer and more reliable to have it done at a professional shop. After all, a car isn't a toy—safety comes first.
Last time I replaced the belt on my family's Chang'an 474 engine by myself, but didn't align it properly. After starting, the engine made terrifying clicking noises. The key steps are: first turn off the engine, use a wrench to rotate the crankshaft to top dead center, and align the small mark on the camshaft. Take a reference photo before removing the belt. When installing, engage each tooth one by one - don't rush, take your time. Adjust the tensioner pulley correctly; the belt can be slightly loose or tight. Rotate it twice to check alignment for peace of mind. Actually consulting the manual is most reliable, but I rushed it that time and made mistakes. Reminder to everyone: double-check multiple times to avoid regrets. Don't lack tools - small wrenches or special pliers are essential. Belt replacement is typically done every 80,000 km - delaying beyond that is high risk. Don't skimp on routine maintenance costs; repairs after failure are more expensive.
