Buick 390300 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 for surface scratches; very shallow scratches can be removed with fine emery cloth or an oil stone, while any deep scoring will require a new camshaft. Mount the camshaft on V-blocks and use a dial gauge to measure lobe lift and run-out, rejecting any camshaft that does not meet the specified limits. Measure the journal diameters with a micrometer and reject any camshaft that does not meet the specified limits. If the bearings are worn, they can be extracted using a suitable tool, such as GM tool set No. J-6098, noting that it will be necessary to drive out the camshaft rear plug from the block. New bearings are installed with the same tool set, ensuring the cam bearing oil holes are aligned correctly: for a small V8, the No. 1 bearing hole should have oil holes equidistant from the 6 o'clock position, while the No. 2 through No. 4 bearing oil holes should be positioned at 5 o'clock, and the No. 5 bearing oil hole at the 12 o'clock position; for a Mark IV V8, the No. 1 through No. 4 oil holes must align with the oil holes in the cam bearing bore, and the No. 5 bearing bore should be at or near the 6 o'clock position. After installing new bearings, install a new camshaft rear plug flush 1/32 inch below and parallel to the rear surface of the block.

Examine the bearing surfaces and the cam lobes; shallow surface scratches can be removed with fine emery cloth or an oil stone, while deep scoring requires a new camshaft. Mount the camshaft on V-blocks and use a dial gauge to measure lobe lift and run-out, rejecting any camshaft that does not meet specified limits. Measure the journal diameters with a micrometer and reject any camshaft that does not meet the specified limits. Worn bearings can be extracted using a suitable tool, such as GM tool set No. J-6098, and it is necessary to drive out the camshaft rear plug from the block. New bearings are installed with the same tool set, ensuring the cam bearing oil holes are aligned: for Small V8, the No.1 bearing hole should have oil holes equidistant from the 6 o'clock position, with No. 2 through No. 4 positioned at 5 o'clock, and the No. 5 bearing oil hole at 12 o'clock; for Mark IV VB, the No.1 through No. 4 oil holes must align with the cam bearing bore oil holes, while the No. 5 bearing bore should be at or near the 6 o'clock position. After installing new bearings, a new camshaft rear plug should be installed flush 1/32 inch below and parallel to the rear surface of the block.

Worn bearings can be extracted using a suitable tool, such as GM tool set No. J-6098.