Toyota Tacoma 3.4 Valve Adjustment

Answer 1

First, you need the proper tools and a clean and dust free place to do this job. You should inspect the timing belt and the water pump as well, since they may also need attention. Replace the timing belt tensioner idler pulley if the bearing is not good. Test this by spinning it by hand. It is not necessary to remove the valve covers to replace the timing belt. For the valve adjustment, you must remove the intake plenum. It is two pieces, the top one is attached to the throttle body. The bottom one is attached to a third intake piece. Get replacement gaskets for these. Leave the throttle cables mounted to the bracket that attaches them to the intake because you don't want to change that adjustment. Once the intake plenum pieces are off, you should clean dirt, grease and oil from the valve covers before you take the covers off. This will prevent dirt from the wire harness and hoses and fuel lines from falling into the valvetrain when the covers are removed. Next remove the covers. Once you have access to the valvetrain, you need to begin measurement of the valve clearances. Intake: (.006-.009"), exhaust: (.011-.014"). Use feeler gauges to measure the clearances between the cam lobe and the valve shim ONLY when the lobe is pointing up. You should write all changes that need to be made for each valve in a small notebook. When you know what size shims you need for each valve that is out of specification, then you must purchase the shims from the dealer. It is easy to remove the shims. You can use a flathead screwdriver to compress the lifter. Next use a smaller flathead screwdriver to take the shim out of the lifter by forcing the screwdriver into the slot on the side of the lifter. Once the smaller screwdriver is under the shim, you can stop compressing the lifter with the larger screwdriver. Next use pair of strong narrow plyers and grab the shim and pull it out of the lifter. Be careful not to scratch the cam lobes. Once a shim is removed, do not crank the engine to align other cam lobes for shim removal since this will damage the cam, and may possibly break the lifter. You must replace the shim before the engine is cranked to align other lobes for shim removal. When the new shims are in place, heck the clearances again. If all are within specifications, then you are just about done. Poured a little new engine oil on all the cam lobes before putting the valve covers back on. Use new O - ring gaskets on the valve covers if the old ones appear cracked or damaged. On the front and back of each head, there is be a semi-circle that the gasket goes over. Put some gasket-forming sealant on the corners where the semi circles begin and end before putting the valve covers back on.