Buick 12507946 Bearing,Camshaft

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When starting to remove the camshaft and camshaft bearings in 196, 231, 252, and 350 Buick Engines, first remove the timing chain and cover. Before pulling out the radiator, unfasten the condenser if your engine is air conditioned. Next carefully dismantle hydraulic lifters to ensure no bearing surface damage while sliding the camshaft forward. The installation of a puller containing puller screw, expanding collet and back-up nut should be done for easy removal of camshaft through removal of the front bearing. Unlike other bearing, this front one can be extracted with a spacer. Reverse these steps during installation ensuring that we replace the whole set of camshaft bearings. In comparison to above mentioned instructions on removal of camshafts; for engines such as 265 or 301 Pontiac Engines which also have similar procedures like intake manifold lifter pushrod rocker arms etcetera should all be removed after removing cam shafts and shaft bearings -particularly where there is A/C in cars; evacuate the system then take away condenser. To perform this task correctly, there are specific tools that are used to remove bearings but their order is different from how they were installed. After lubricating the camshaft and aligning timing marks we put it back together with distributor in place. The rest are placed back on opposite order. Disconnection of battery; draining and taking off radiator; disassembly of different parts such as intake manifold valve lifters timing chain sprockets among others will be involved in dismantling process of these engines such as those in Oldsmobile Gasoline Engines 307,350 and 403.Very carefully extract the camshaft; replace them together with lubricating both them and the beam before reinserting it. Put distributor back while ensuring alignment with timing marks on it so that it rotates around crankshaft at proper instant when engine is running again. Assemble all pieces backwards and make sure to observe some steps and precautions. Removing the camshaft necessitates removing the injection pump drive and driven gears, intake manifold, valve lifters, then retiming of the injection pump for 263 and 350 Oldsmobile Diesel Engines. In case of air conditioning system, it should be discharged. Then remove camshaft and gears ensuring correct alignment and if necessary replace both gears. After lubricating the camshaft and bearings slide it back carefully into place. It is now time to re-align and install gears; injection pump with others in reverse order as per instruction on end play adjustment as well as timing.

Examine the bearing surfaces and the surfaces of the cam lobes; surface scratches, if very shallow, can be removed by rubbing with a fine emery cloth or an oilstone, while any deep scoring will necessitate a new camshaft. If the bearings are worn, they can be extracted using a suitable tool, such as GM tool set No. J-6098, which is designed for this purpose, and it will be necessary to drive out the camshaft rear plug from the back. New bearings are installed using the same tool set, ensuring to align the cam bearing oil holes according to the manufacturer's instructions supplied with the installation/removal tool.

After removing the camshaft from the engine, clean it with solvent and dry it, then inspect the bearing journals for uneven wear, pitting, and evidence of seizure; if damaged, both the camshaft and bearings will need replacement. Measure the inside diameter of each camshaft bearing, taking two measurements at each bearing, and subtract the bearing journal diameters from the corresponding bearing inside diameter measurement to obtain the oil clearance; excessive clearance necessitates new bearings. Camshaft bearing replacement requires special tools and expertise, so it is advisable to take the block to an automotive machine shop. Check the camshaft lobes for heat discoloration, score marks, chipped areas, pitting, and uneven wear; if the lobes are in good condition and the lobe lift measurements are as specified, the camshaft can be reused. Good used roller lifters can be reinstalled with a new camshaft, and while the original camshaft can be used if new lifters are installed, it is recommended to replace both together, especially for high-mileage engines. For V6 engines, if the balance shaft is to be removed, the balance shaft gear bolt should be removed before the timing chain to hold the shaft while loosening the bolt. Remove the two bolts and the balance shaft retainer at the front of the block, then use a slide-hammer threaded into the front of the balance shaft to knock it out. Inspect the balance shaft and measure the bearing journal diameters; if measurements exceed specifications, replace the balance shaft, bearing, and bushing as a set. The rear bushing, similar to a camshaft bearing, must be installed by a machine shop with the proper tools and alignment. Inspect the balance shaft drive gear and the balance shaft driven gear for signs of wear, pitting, broken teeth, or rough operation, as both gears are serviced only as a set.

After removing the camshaft from the engine, clean it with solvent and dry it, then inspect the bearing journals for uneven wear, pitting, and evidence of seizure; if damaged, both the camshaft and bearings will need replacement. Measure the inside diameter of each camshaft bearing, taking two measurements at each bearing, and subtract the bearing journal diameters from the corresponding bearing inside diameter measurement to obtain the oil clearance; excessive clearance necessitates new bearings. Camshaft bearing replacement requires special tools and expertise, so it is advisable to take the block to an automotive machine shop. Check the camshaft lobes for heat discoloration, score marks, chipped areas, pitting, and uneven wear; if the lobes are in good condition and the lobe lift measurements are as specified, the camshaft can be reused. Good used roller lifters can be reinstalled with a new camshaft, and while the original camshaft can be used if new lifters are installed, it is recommended to replace both together, especially for high-mileage engines. For V6 engines, if the balance shaft is to be removed, the balance shaft gear bolt should be removed before the timing chain to hold the shaft while loosening the bolt. Remove the two bolts and the balance shaft retainer at the front of the block, then use a slide-hammer threaded into the front of the balance shaft to knock it out. Inspect the balance shaft and measure the bearing journal diameters; if measurements exceed specifications, replace the balance shaft, bearing, and bushing as a set. The rear bushing, similar to a camshaft bearing, must be installed by a machine shop with the proper tools and alignment. Inspect the balance shaft drive gear and the balance shaft driven gear for signs of wear, pitting, broken teeth, or rough operation, as both gears are serviced only as a set.

To remove the camshaft, the following steps are involved:Remove the timing chain and sprockets.Remove lifters and pushrods.Remove the oil pump drive.

Camshaft bearing replacement requires special tools and expertise, so it is advisable to take the block to an automotive machine shop for proper handling.