How to replace a broken timing belt
Daewoo has interference engines in them, so if the timing belt broke while the engine was running, you will need to replace half of the valves which were bent when the pistons crashed into them when the cams stopped turning and the crank shaft continued to turn. Minimum of $700-1000.00 (usually more). If you do it all yourself and the valve guides are not damaged, still at least $400.00 worth of parts to fix. Pull plastic air dams around bottom of engine on front and right side . Support engine with jack. Drain antifreeze from engine and radiator. remove air filter housing and serpentine belt. remove front engine mount. remove cam belt cover. remove broken cam belt and check cam tensioner bearings and idler bearing as well. They are usually bad. Then remove spark plug cover. Remove valve cover. Remove intake from head. remove coil from head. remove heat shield from exhaust manifold then remove manifold from exhaust and from head. remove water hoses and connecting assemblies from side of head and rear of head. remove Cam shaft bearing caps loosening them all evenly so as not to bend cams. remove cams. remove head bolts. remove head. remove valve hydraulic lifters, compress valve springs and remove valve retainers and dissassemble valves. Clean everything very well. Make sure head is not damaged. Remove valve guide seals. install new valve guide seals, new valves. Seat valves with valve grinding compound. clean well. instal valves in reverse order of dissasembly. Before putting head on, make sure number 1 cylinder is at top dead center position. install head using proper torque of 18 ft # in a spiral application rotation from the center outward in a clockwise direction. Then do spiral rotation again tightening bolts each one-quarter turn. Repeat the tightening process two more times only turning the bolts one-quarter turn each time. Use new head bolts. They are designed to stretch in the process of installation and are not to be re-used. Align cams to proper orientation then bolt into place. do not overtorque cam bearing cap bolts. Less than 5 ft # of torque can stretch these bolts. Snug them then tighten them 90 degrees. Then tighten them another 90 degrees (quarter turn). Snug them all then go back and tighten all of them a quater turn, then go back and tighten all of them another quarter turn. Install the cam idler and tensioner and install the cam belt. then install the intake, exhaust and all other items in reverse order of assembly. Do not turn engine over unless you are sure you have the cam belt on with the crank shaft pulley aligned at top dead center and the intake and exhauste pulley marks aligned to their proper marks with the cam belt properly tensioned. You can't be even one tooth off. This must be right before you turn the engine over! Remove spark plugs and turn engine over by hand two rotation clockwise using a wrench on the center bolt of the crank shaft pulley. Check that the timing of cams is still perfect. If not, correct, retension cam belt, double check timing positions again then rotate engine two revolutions. Check cam timing positions again. The timing should not change! The engine should turn over relatively easily. If it feels like it doesn't want to turn, don't force it. You may have the timing off and be pressing a piston against a valve. If you are at this point, then you need to remove cam belt and unbolt cam shafts to release all tension on any of the valves. return the number one cylinder to top dead center position and then reinstall the cams and cam belt. Once it is assembled and in time, then reattatch the rest of the components that were removed in dissassembly. Do this in reverse order of dissassembly. then connect battery and fill radiator fluid. Start car.
Aug 31, 2010 |
Daewoo Nubira Cars & Trucks