Pontiac 19256448 Bearing Kit,Connect Rod

When overhauling an engine, it is standard practice to replace the main and connecting rod bearings with new ones, but it is useful to retain the old bearings, as these will reveal much about the condition of the engine. Some of the causes of bearing failure include inadequate lubrication, the presence of dirt or foreign particles, overloading the engine and corrosion, all of which have to be eliminated before re-fixing the engine for the same not to recur again. While inspecting the bearings they should be taken out of the engine parts and arranged in the same position on a flat surface so that in case of any flaw it may be matched with the crank shaft journal. Particles from other sources can be introduced in the engine during assembly time or through the filters, the PCV system, or can be residual chips or abrasives from a previous machining or reconditioning. The former may get lodged within the bearing material, while the latter score or gouge the bearing surface. To avoid such failures the interior as well as the exterior part of the car should be well cleaned and the oil and filter should be changed. Crushing of bearing due to lack of lubrication is normally due to heat stress, overloading, oil leaking or blocked oil ways and results in the bearing material being wiped fully off its backing. Some driving practices also affect bearing life in a vehicle; for example very low speed with a full throttle puts a lot of load which forces out the oil in the bearings while short journeys may cause corrosion owing to low heat generation. Also, incorrect bearing fitment leads to lasting oil starvation, or high spots that lead to failure sometimes.

In most cases when the engine is overhauled one is required to remove the main & connecting rod bearings then replace them with fresh ones while the removed bearings act as a bench reference on the status of the engine. Failure of bearings mainly results from lack of lubrication, presence of dirt or other particles, overloading of engine, and rusting hence corrections must be done before assembly to avoid the same. While inspecting the bearings they should be withdrawn from the particular place or area and arranged on the clean surface so that they can be match-marked or compared to the crankshaft journal. Contaminants can be brought into the engine during assembly, thru filters, or from machining operations and become lodged in the bearing material and cause scoring or gouging. To avoid this, all parts should be cleansed properly, and the oil and filter changed as often as should be. Lubrication can fail by burn-off, over; loading, leakage of oil, or plugging of the oil passages, and consequent severe damage may include the bearing material being extruded from its backing. There are also driving habits, which have considerable effect on bearings; for example, luging the engine will cause high loads and short trip causes corrosion. Further, improper bearing installation also shorten the life of the bearing as they can cause proper oil starved or, high spots that leads to failure.

Depend on whether internal or external oil filtration is to be performed, it is necessary to dismantle the oil pan, oil pump, and cylinder heads. Before pushing the piston assemblies upwards through the top of the engine block, employ the services of a ridge reamer to remove the ridge or carbon deposits at the top of the cylinder.When using the ridge reamer, work on one cylinder at a time. To resurface the piston top, start the engine and turn it to bottom the piston, put a rag over the piston to catch the cuttings and with the ridge removed, invert the engine to remove the cloth and cuttings. Check the connecting rods and caps for the cylinder numbers and put number on them, if not done, using small punch. Take out the nuts on the connecting rod stud in order and raise off the cap on the crankshaft, lay the parts side by side with each cylinder on a clean surface labeled. Apply rubber or plastic tubing on the connecting rod studs for precaution to avoid damaging the crankshaft or the cylinder wall during the disassembling of the piston assembly. Remove the piston/connecting rod assembly through the cylinder head and position the connected rod cap in the sequenced work area with referring the diagram which is given above and repeat the process for the remaining cylinder again placing the protective tubing in proper position. Pop out the small screws with which the bearing and cap and the connecting rods are connected and if the bearings are heavily used due to the many miles the engine has covered it is recommended to replace the bearings. If possible, then by the help of piston ring expanding tool, take every ring from the piston, otherwise, try to expand the ring just enough and then take the help of tin strips for taking the ring out of the piston body. Put the rings in its installed order together with the piston/connecting rod on the work area indicated with numbers. To remove the connecting rod from the piston, remove the piston pin, this can hardly be done by a mere mechanic and it is advisable to be done by the dealer or automotive machine shop who will have the appropriate tools for the job. It is better to leave the piston/rod assemblies uncleaned and un-inspected at this juncture because depending on the state of the cylinder block or crankshaft, these components may have to be replaced.

In most cases when the engine is overhauled one is required to remove the main & connecting rod bearings then replace them with fresh ones while the removed bearings act as a bench reference on the status of the engine. Failure of bearings mainly results from lack of lubrication, presence of dirt or other particles, overloading of engine, and rusting hence corrections must be done before assembly to avoid the same. While inspecting the bearings they should be withdrawn from the particular place or area and arranged on the clean surface so that they can be match-marked or compared to the crankshaft journal. Contaminants can be brought into the engine during assembly, thru filters, or from machining operations and become lodged in the bearing material and cause scoring or gouging. To avoid this, all parts should be cleansed properly, and the oil and filter changed as often as should be. Lubrication can fail by burn-off, over; loading, leakage of oil, or plugging of the oil passages, and consequent severe damage may include the bearing material being extruded from its backing. There are also driving habits, which have considerable effect on bearings; for example, luging the engine will cause high loads and short trip causes corrosion. Further, improper bearing installation also shorten the life of the bearing as they can cause proper oil starved or, high spots that leads to failure.

In most cases when the engine is overhauled one is required to remove the main & connecting rod bearings then replace them with fresh ones while the removed bearings act as a bench reference on the status of the engine. Failure of bearings mainly results from lack of lubrication, presence of dirt or other particles, overloading of engine, and rusting hence corrections must be done before assembly to avoid the same. While inspecting the bearings they should be withdrawn from the particular place or area and arranged on the clean surface so that they can be match-marked or compared to the crankshaft journal. Contaminants can be brought into the engine during assembly, thru filters, or from machining operations and become lodged in the bearing material and cause scoring or gouging. To avoid this, all parts should be cleansed properly, and the oil and filter changed as often as should be. Lubrication can fail by burn-off, over; loading, leakage of oil, or plugging of the oil passages, and consequent severe damage may include the bearing material being extruded from its backing. There are also driving habits, which have considerable effect on bearings; for example, luging the engine will cause high loads and short trip causes corrosion. Further, improper bearing installation also shorten the life of the bearing as they can cause proper oil starved or, high spots that leads to failure.

In most cases when the engine is overhauled one is required to remove the main & connecting rod bearings then replace them with fresh ones while the removed bearings act as a bench reference on the status of the engine. Failure of bearings mainly results from lack of lubrication, presence of dirt or other particles, overloading of engine, and rusting hence corrections must be done before assembly to avoid the same. While inspecting the bearings they should be withdrawn from the particular place or area and arranged on the clean surface so that they can be match-marked or compared to the crankshaft journal. Contaminants can be brought into the engine during assembly, thru filters, or from machining operations and become lodged in the bearing material and cause scoring or gouging. To avoid this, all parts should be cleansed properly, and the oil and filter changed as often as should be. Lubrication can fail by burn-off, over; loading, leakage of oil, or plugging of the oil passages, and consequent severe damage may include the bearing material being extruded from its backing. There are also driving habits, which have considerable effect on bearings; for example, luging the engine will cause high loads and short trip causes corrosion. Further, improper bearing installation also shorten the life of the bearing as they can cause proper oil starved or, high spots that leads to failure.

Tight fitting bearings or trapped dirt or foreign particles.

For connecting rod bearing clearances: 1. Install each piston/rod assembly. 2. Use Plastigage as previously described. 3. Check connecting rod side clearance.

It is important to check that all the piston ring gaps are positioned properly.

They can provide valuable information about the engine's condition.