GM 24505811 Camshaft, (Machining)

For camshaft and intermediate shaft installation in the 3.4L engine, lubricate the camshaft bearing journals and cam lobes with moly-base grease or engine assembly lube before installation. Slide the camshaft into the engine using a long bolt as a handle, supporting it near the block to avoid damaging the bearings. Install the camshaft retainer plate or intermediate shaft plate and tighten the bolts to the specified torque. For 2.5L engines through 1990, align the timing marks on the camshaft gear and crankshaft gear, then install and tighten the thrust plate bolts. For 2.2L four-cylinder and V6 engines (excluding 3800), dip the oil pump drive gear in engine oil and insert it into the block, ensuring it is flush with the mounting boss before securing it with a retaining bolt, and position a new O-ring on the oil pump drive shaft. Proceed with the installation of the lifters, timing chain, and sprockets based on the engine type. For the 3800 engine, lubricate the front bearing and rear journal of the balance shaft with engine oil, carefully insert it into the block, and use a hammer and socket to drive the front bearing into its insert just enough to install the balance shaft bearing retainer, then tighten the retainer bolts. Install the balance shaft driven gear and its bolt, turn the camshaft so the timing mark is straight down with the camshaft sprocket temporarily installed, and then turn the balance shaft so its timing mark points straight down. Install the camshaft gear that drives the balance shaft, aligning it with the keyway and matching the marks on both balance shaft gears by turning the balance shaft. Finally, after installing the camshaft sprocket, crankshaft sprocket, and timing chain, tighten the balance shaft driven gear bolt to the specified torque.

To measure camshaft lobe lift with the cylinder head installed remove the valve cover(s) and place the number one piston at the top center of the compression stroke. Bolt a dial indicator on the engine such that the face of the plunger is on a plane with the top of the first rocker arm above the pushrod. Rotate the dial indicator back to zero and then take a slow turn of the crankshaft clockwise until the pointer appears to stop and begin moving in the opposite direction-this will be the maximum cam lobe lift. Make a record of this measurement and turn the piston to TDC before proceeding with the same on the other valves, each piston having to be on TDC on the compression stroke. After passing through the checks, one is supposed to compare the results gotten with the specification; in case the lobe lift is below the specified value it indicates that the cam lobe is worn and, therefore, requires a new camshaft. If the cylinder head is removed, using the micrometer measure the lobe height and also measure the base circle to find out lobe lift by subtracting the base circle from lobe height. In the particular case of extracting the camshaft, one should first of all, eliminate lifters and pushrods, and in case of its presence, timing chain and sprockets. In some engines, it is necessary to take out the oil pump drive, and in the camshaft sprocket bolt hole, there should be long bolts to make wielding easier. Take off the camshaft thrust plate then slide out the camshaft or intermediate shaft in a manner that will not harm the bearings. During balance shafts, they should have a check on the gear backlash and end play measurement with the replacement of the parts involved. Following removal of the camshaft, the cleaning and checking of the camshaft and cam bearings for wear or damages should be done then the inspection of the camshaft and cam bearings should in order to identify if new ones are required for measuring. If the timing gear has to be removed, it has to be pressed off and then hammered back on and checking end clearance and bearing journal diameter for wear gauge. If there is any sign of wear beyond normal you will need new bearings; the camshaft and balance shaft bearings should be replaced by a professional.

Finally, road test the vehicle and check for oil and coolant leaks.