GM 88894280 Piston Asm,(W/ Pinion)(Std)

Before the piston and its respective connecting rods are fixed on the engine, it is required to check if the cylinder walls are free from deposits, the top edges of each cylinder are peened, and the crankshaft is inserted into the engine block. Bolt off the cap of the No 1 connecting rod, and replace the bearing inserts with the new ones, and clean the bearing surface of the rod lightly with a clean cloth. Clean the back side of the new upper bearing half and bring it into the connecting rod in such way that the tab should fit into the recess without hammering the tab into position and damaging the bearing face. Do this same thing with the other bearing insert that sits in the rod cap also ensure that all mating surfaces are clean and free from oil. Make sure that positions of the gap of the piston rings are at intervals of every 120 degrees, apply a few drops of clean engine oil at the land of the piston and the ring, fit the piston ring compressor in such way that ¼ inch of the piston skirt comes out. Turn the crankshaft such that the number one connecting rod journal is at the bottom dead centre, then apply a liberal coat of oil on the cylinder walls. Place the piston/connecting rod assembly into the cylinder bore, so that to the notch would look forward and the ring compressor should be in contacting the block. Hit the piston lightly with wooden hammer handle and ease the connecting rod over the crankshaft journal carefully if one feels any rigidity. When the connecting rod is in position, it is recommended that one should check the bearing oil clearance before finally tightening the cap of the rod. Place a thin layer of Plastigage on the journal of the connecting rod, apply clean oil on the rod cap bearing face and finally screw and align the cap against the marks on the journals. Make up the nuts to the required torque in that sequence while the crankshaft is immobilated. The upper part of the check rod was also protected with Plastigage and lifting the rod cap cautiously allowed getting a clearance on this scale as no dirt or oil would appear to have influenced the width on the Plastigage. Scrape of any Plastigage material from the rod journal surface and bearing face, spread a fresh layer of moly-base grease or engine assembly lube on the rod journal and fit the rod again on the journal. Anchoring the rod cap nuts to the appropriate amplitude of torque, do the same for the other staying assemblies while at the same time ensuring that all the components are free from dirt. It is only possible to do this after next all the assemblies are installed, rotate the crankshaft manually, and at the end of this process, measure the connecting rod end play and adjust, if it has deviations from the norm.

Prior to removing the piston and connecting rod assemblies, position the engine upright. Use a ridge reamer to completely eliminate the ridge at the top of each cylinder, following the manufacturer's instructions, as failure to do so may result in piston breakage. Once all cylinder wear ridges are removed, turn the engine upside-down. Before removing the connecting rods, check the endplay by mounting a dial indicator aligned with the crankshaft and touching the side of the number one cylinder connecting rod cap. Push the connecting rod forward to zero the dial indicator, then push it to the rear and note the reading; if the endplay exceeds the service limit, a new connecting rod is necessary. Alternatively, feeler gauges can be used to measure the endplay by inserting them between the connecting rod and crankshaft throw until the play is eliminated. Check for identification marks on the connecting rods and caps, and if absent, use a small punch to mark them. Loosen each connecting rod cap nut about half a turn, remove the number one connecting rod cap and bearing insert without dropping the insert, and protect the crankshaft journal and cylinder wall by slipping a short length of plastic or rubber hose over each connecting rod cap bolt before pushing the connecting rod/piston assembly out through the top of the engine with a wooden tool. If resistance is encountered, ensure all ridge material has been removed. Repeat this process for the remaining cylinders, and after removal, reassemble the connecting rod caps and bearing inserts in their respective rods, installing the cap nuts finger tight to prevent accidental damage to the bearing surfaces.

The inspection process for the piston/connecting rod assemblies should start by cleaning them and removing the original piston rings from the pistons, then replacing them with new piston rings during engine reassembly. With care to avoid damaging the piston surfaces, pull out the rings using a piston ring installation tool. By scraping or using a handheld wire brush or fine emery cloth, eliminate carbon deposits from the piston crown. Avoid electric drills with wire brushes as these can eat away at the soft material of the piston. Use a piece from an old ring or a piston ring groove cleaning tool to get rid of carbon deposits from the ring grooves without removing any metal or causing scratches. Consequently, solvent-wash and blow off each of them if possible in order that oil return holes are not clogged on their back sides within ring grooves. Also, check for cracks around skirt, pin bosses and ring lands or overheating/abnormal combustion scoring, scuffing, holes or burned areas in thrust faces, crown and edge which need addressing if found. If there is corrosion with small pits it may indicate coolant leakage; this must be sorted out. Piston to bore clearance; measure clearances on one side of the compressor guard ensuring perfect match so as to check out for proper fitting: plus evaluate piston -to-rod clearance seeking help of automotive machine shop for reboring and new pin installation whenever necessary. In case it becomes necessary to separate pistons from connecting rods, professional assistance must be sought in order not to disassemble pistons and connecting rods also. Finally, check connection rod for cracks/damages, remove rod caps temporarily to inspect bearing surfaces and replace old bearings before tightening nuts finger tight.

Before the piston/connecting rod assemblies are removed, take off cylinder heads, oil pan and the oil pump. Using a ridge reaming tool, completely eliminate any ridge existing at the top of each cylinder. If this is not done before removing them, pistons will be broken. Fold engine up-side down so that the crankshaft is turned facing upwards after removal of ridges from cylinders. It is important to check end play on connecting rods with a feeler gauge before they can be removed. Place the first feeler gauge in between crankshaft throw and first connecting rod until all play is gone. The endplay equals to one or more thicknesses of feeler gauges if used together in a stack. When endplay exceeds service limit for wear, it means new connecting rods will have to be installed. Any identification marks should be on caps and rods of connection Check All marks are checked bearing Let every single nut on the cap of a connecting rod loosen by half turn until it comes out by hand Remove bear- ing insert remove Wear safety glasses throw Protects walls while also protecting journals Push down on upper bearing Use wood Hammer handle Double-check for forgotten ridges or pieces within individual bores Repeat for each remaining bore After disassembly install nuts onto cap bolts so that caps may take place upon bearings without tightening them too far Use old inserts when cleaning journals prior to reassembly.

The first step in installing piston/connecting rod assemblies is to make sure that the cylinder walls are spotless, chamfer the top edge of each cylinder and to have placed crankshaft correctly. So, remove number one connecting rod cap from its end and thereafter remove old bearing inserts and carefully wipe off all bearing surfaces of both connecting rod and cap. For this reason, they should remain absolutely clean. New upper half of a bearing should be cleaned on its opposite side before being put within a piston pin bore with its tab fitting securely into the recess in a rod. The same procedure should then be followed for the other bearing insert installed in the cap of the rod; ensuring that it lines up with tab on cap's recesses. At this point do not lubricate bearings yet. Leave ring gap spacing intact, lubricate piston and rings with clean engine oil before attaching piston ring compressor to the piston hand tool/fixture. Ensure that compressor sits on bottom edge of an engine block while inserting piston into number one cylinder bore such that its notch faces front of an engine. Gently tap down all pistons putting rods lightly on top of crankshaft journals being careful not to force them onto place making sure number one cylinder bore face is towards front direction as well as lower edge of compressor touches engine block gently guiding connecting rods down into correct positions by tapping pistons only slightly during assembly process to avoid damage but also ensure all pistons compression rings are facing upwards . After you have fixed piston/connecting rod assembly at their place you must check oil clearance in connecting rod bearings prior to tightening down these nuts permanently Since it is necessary lay Plastigage across number one connecting rod journal then install the cap getting mating marks lined up properly and then tighten nuts according to specified torque over three steps Thereafter don't disturb Plastigage if it is there while removing rod cap; then simply compare width between flattened Plastigage taken from scale and the value in Specifications to confirm oil clearance accordingly. Lastly, remove all Plastigage material from rod journal and bearing face thereby ensuring that no marks or imperfections are left behind on them; wipe clean both of these surfaces so that they can be completely dry and then apply a thin coat of moly-based grease evenly over them. To expose face of bearing insert in connecting rod push piston into cylinder, slide the rod back onto journal, take off protective hoses from rod cap bolts, tighten down nuts according to specified torque through three steps for this reason. Repeat this process for all remaining pistons/connecting rods. Rotate the crankshaft by hand to check for any obvious binding Finally, make sure that the end play is within specifications as presented in Specifications table by measuring each connecting rod end-play value against its required values; if brand new rods or a new crank shaft were used resizing might be necessary at automotive machine shop when end play is excessively low.

The first step in installing piston/connecting rod assemblies is to make sure that the cylinder walls are spotless, chamfer the top edge of each cylinder and to have placed crankshaft correctly. So, remove number one connecting rod cap from its end and thereafter remove old bearing inserts and carefully wipe off all bearing surfaces of both connecting rod and cap. For this reason, they should remain absolutely clean. New upper half of a bearing should be cleaned on its opposite side before being put within a piston pin bore with its tab fitting securely into the recess in a rod. The same procedure should then be followed for the other bearing insert installed in the cap of the rod; ensuring that it lines up with tab on cap's recesses. At this point do not lubricate bearings yet. Leave ring gap spacing intact, lubricate piston and rings with clean engine oil before attaching piston ring compressor to the piston hand tool/fixture. Ensure that compressor sits on bottom edge of an engine block while inserting piston into number one cylinder bore such that its notch faces front of an engine. Gently tap down all pistons putting rods lightly on top of crankshaft journals being careful not to force them onto place making sure number one cylinder bore face is towards front direction as well as lower edge of compressor touches engine block gently guiding connecting rods down into correct positions by tapping pistons only slightly during assembly process to avoid damage but also ensure all pistons compression rings are facing upwards . After you have fixed piston/connecting rod assembly at their place you must check oil clearance in connecting rod bearings prior to tightening down these nuts permanently Since it is necessary lay Plastigage across number one connecting rod journal then install the cap getting mating marks lined up properly and then tighten nuts according to specified torque over three steps Thereafter don't disturb Plastigage if it is there while removing rod cap; then simply compare width between flattened Plastigage taken from scale and the value in Specifications to confirm oil clearance accordingly. Lastly, remove all Plastigage material from rod journal and bearing face thereby ensuring that no marks or imperfections are left behind on them; wipe clean both of these surfaces so that they can be completely dry and then apply a thin coat of moly-based grease evenly over them. To expose face of bearing insert in connecting rod push piston into cylinder, slide the rod back onto journal, take off protective hoses from rod cap bolts, tighten down nuts according to specified torque through three steps for this reason. Repeat this process for all remaining pistons/connecting rods. Rotate the crankshaft by hand to check for any obvious binding Finally, make sure that the end play is within specifications as presented in Specifications table by measuring each connecting rod end-play value against its required values; if brand new rods or a new crank shaft were used resizing might be necessary at automotive machine shop when end play is excessively low.

Before the piston/connecting rod assemblies are removed, take off cylinder heads, oil pan and the oil pump. Using a ridge reaming tool, completely eliminate any ridge existing at the top of each cylinder. If this is not done before removing them, pistons will be broken. Fold engine up-side down so that the crankshaft is turned facing upwards after removal of ridges from cylinders. It is important to check end play on connecting rods with a feeler gauge before they can be removed. Place the first feeler gauge in between crankshaft throw and first connecting rod until all play is gone. The endplay equals to one or more thicknesses of feeler gauges if used together in a stack. When endplay exceeds service limit for wear, it means new connecting rods will have to be installed. Any identification marks should be on caps and rods of connection Check All marks are checked bearing Let every single nut on the cap of a connecting rod loosen by half turn until it comes out by hand Remove bear- ing insert remove Wear safety glasses throw Protects walls while also protecting journals Push down on upper bearing Use wood Hammer handle Double-check for forgotten ridges or pieces within individual bores Repeat for each remaining bore After disassembly install nuts onto cap bolts so that caps may take place upon bearings without tightening them too far Use old inserts when cleaning journals prior to reassembly.

Before these, one will have to strip down the cylinder heads and oil pan to get access to the piston and connecting rod assemblies. You should also occasionally look at the upper limit of ring travel, about 1/4 of an inch from the top of each cylinder, for any ridge; if there are ridges there due to carbon deposits or wear, they must be done away with using a ridge reamer to avoid causing the piston to break. Once the ridges have been taken off, position the engine in a way that the crankshaft is vertically upward. The other is to compare the connecting rod endplay as measured by feeler gauges with the service limit of 0.005 - 015 inch; if greater than this limit, it may require new connecting rods. Locate the connecting rods and caps easily so that they are not confused and when loosening the connecting rod cap bolts or nuts, it is done progressively such that they can be overstated by hand. Take out the first connecting rod cap and the bearing insert without the insert falling off and push the connecting rod and piston assembly out from the top of the engine use the wooden or plastic hammer handle if possible. Perform this to the rest of the cylinders replacing the old rod cap bolts, if any, with new ones. Because of the tension between the joint and the bearing, if the caps and bearing inserts are removed it is advisable to replace them in their original positions as re-creating tension could damage them. Pistons and connecting rods are now available for inspection and rebuilding or replacement if necessary. When new piston rings are to be fitted, measure the ring end gaps, to ensure that the side clearance of the piston ring is correct. Specify the location and orientation of the piston/connecting rod assemblies and the new rings in order to match them again for assembly. Place the top ring above the first cylinder, align with cylinder bore walls and do an end gap measurement using feeler gauges adjusting as necessary. Make sure you fit the oil control ring first then the middle and finally the top ring making sure you have the correct side up. Do not install nitrided cylinders if the cylinder walls are contaminated, the top edge of each cylinder bored is not chamfered, and the crankshaft is not inserted into the cylinder. Scrape off the bearing surfaces of the connecting rod and cap and fit the new upper bearing insert, that must be a tight fit, but not stick, without using oil. Adjust the position of the ring with reference to the cylinder and lubricate the piston and rings, to compress the piston ring use a piston ring compressor. Place the piston/connecting rod assembly into the cylinder bore such that the piston faces the right way and then gently drive in the piston until it hits the bottom of the cylinder bore while at the same time aligning the connecting rod with the crankshaft journal. Measure the oil clearance of the connecting rod bearing using Plastigage after which the bearing faces should be clean and grease or assembly lube applied before final assembly. This will be followed by the same process for the other four OTR assemblies and make sure they are clean and properly oriented. Following installation, turn the crankshaft to inspect the corresponding amount of tightness or recheck the connecting rod's end float then resize, if needed.

The inspection process for the piston/connecting rod assemblies should start by cleaning them and removing the original piston rings from the pistons, then replacing them with new piston rings during engine reassembly. With care to avoid damaging the piston surfaces, pull out the rings using a piston ring installation tool. By scraping or using a handheld wire brush or fine emery cloth, eliminate carbon deposits from the piston crown. Avoid electric drills with wire brushes as these can eat away at the soft material of the piston. Use a piece from an old ring or a piston ring groove cleaning tool to get rid of carbon deposits from the ring grooves without removing any metal or causing scratches. Consequently, solvent-wash and blow off each of them if possible in order that oil return holes are not clogged on their back sides within ring grooves. Also, check for cracks around skirt, pin bosses and ring lands or overheating/abnormal combustion scoring, scuffing, holes or burned areas in thrust faces, crown and edge which need addressing if found. If there is corrosion with small pits it may indicate coolant leakage; this must be sorted out. Piston to bore clearance; measure clearances on one side of the compressor guard ensuring perfect match so as to check out for proper fitting: plus evaluate piston -to-rod clearance seeking help of automotive machine shop for reboring and new pin installation whenever necessary. In case it becomes necessary to separate pistons from connecting rods, professional assistance must be sought in order not to disassemble pistons and connecting rods also. Finally, check connection rod for cracks/damages, remove rod caps temporarily to inspect bearing surfaces and replace old bearings before tightening nuts finger tight.

Prior to removing the piston and connecting rod assemblies, position the engine upright. Use a ridge reamer to completely eliminate the ridge at the top of each cylinder, following the manufacturer's instructions, as failure to do so may result in piston breakage. Once all cylinder wear ridges are removed, turn the engine upside-down. Before removing the connecting rods, check the endplay by mounting a dial indicator aligned with the crankshaft and touching the side of the number one cylinder connecting rod cap. Push the connecting rod forward to zero the dial indicator, then push it to the rear and note the reading; if the endplay exceeds the service limit, a new connecting rod is necessary. Alternatively, feeler gauges can be used to measure the endplay by inserting them between the connecting rod and crankshaft throw until the play is eliminated. Check for identification marks on the connecting rods and caps, and if absent, use a small punch to mark them. Loosen each connecting rod cap nut about half a turn, remove the number one connecting rod cap and bearing insert without dropping the insert, and protect the crankshaft journal and cylinder wall by slipping a short length of plastic or rubber hose over each connecting rod cap bolt before pushing the connecting rod/piston assembly out through the top of the engine with a wooden tool. If resistance is encountered, ensure all ridge material has been removed. Repeat this process for the remaining cylinders, and after removal, reassemble the connecting rod caps and bearing inserts in their respective rods, installing the cap nuts finger tight to prevent accidental damage to the bearing surfaces.

Before the inspection process can be carried out there is need to; have the piston/connecting rod assemblies cleaned and to have the original piston rings removed from the pistons and replaced by new ones when reassembling the engines. Utilizing the piston ring installation tool, take out the piston rings off the pistons and be keen to ensure that they do not develop nicks or gouges on them. Remove all the carbon deposits on the top of the piston by hand held brass wire brushing or fine emery paper should be used and never used steel wire as it will erode the piston material. Carbon build up on the piston should be wiped out by a piston ring groove cleaner; if this is not available, use a piece of broken old ring; ensure that you do not remove any metal and damage the grooves. When deposits are taken out, the piston/rod assemblies should be cleaned using solvent or solvent and compressed air and should check that oil holes are clear of obstruction. If pistons are not damaged and engine block has not been rebored, new pistons maybe not required, but new piston rings should always be fit during rebuilds. Each piston should be checked for cracks, scoring, scuffing, holes and burned looks as all these are signs of overheating or abnormal combustion and checks should, therefore, be made of the cooling and lubricating arrangements. If bleed had occurred leading to coolant leakage as manifested by corrosion indicated by pitting this must be dealt with to avoid such occurrence in the future. Take the adequate measurement of the side clearance of the piston rings with the help of a feeler gauge measuring each ring groove at different places; this should be proceeded with the selection of an appropriate ring for every groove; too much clearance may necessitate the replacement of the piston. Piston to bore check, with dial bore gauge, bore and piston diameter should be matching and calculate the clearance; if clearance more than limiting number then block rebore and new piston and piston rings must be fitted. This is normally done by twisting the piston and the rod; any amount of free play, which is often easily discernible, suggests that it has worn and this will need rectification, possibly by getting a new a piston-pin and rebore from an automotive machine shop. If pistons require to be separated from connecting rods, then they should be sent to a machine shop for assessment of bend and twist, and should be dismantled only if essential. Last but not least, ensure that connecting rods are free from cracks and other damages; for this, you need to loosen the rod cap, look at the bearing surfaces to see that they are free from c sporadic nicks or scratches and replace the old bearings; later, you should tighten the cap.

The piston/connecting rod assemblies must be cleaned, and the original piston rings must be removed from the pistons. New piston rings should always be used during reassembly.

Ensure not to drop the bearing insert and protect the crankshaft journal and cylinder wall by slipping a short length of plastic or rubber hose over each connecting rod cap bolt.

Clean the back side of the other bearing insert and install it in the rod cap, again ensuring the tab fits into the recess without applying lubricant.

Assess piston-to-rod clearance by twisting the piston and rod; noticeable play indicates excessive wear that needs correction, potentially requiring a visit to an automotive machine shop for new piston pins and rebore.

Scrape all traces of carbon from the top of the piston using a hand-held wire brush with brass bristles or fine emery cloth. Avoid using a steel wire brush to prevent erosion of the soft piston material.

Remove the rod cap carefully to avoid disturbing the Plastigage, then compare the width of the crushed Plastigage to the scale on the container to obtain the oil clearance, ensuring it meets specifications.

After installing all piston/connecting rod assemblies, you should rotate the crankshaft by hand to check for any binding. It is also important to check the connecting rod endplay for correctness. If necessary, the rods may need to be taken for resizing if new components were installed.

Before removing piston/connecting rod assemblies, you should check for ridges at the upper limit of ring travel in each cylinder and remove them if present to avoid piston breakage. You should also verify connecting rod endplay with feeler gauges and address any deviations to ensure it falls within the service limit.

Slip a short length of plastic or rubber hose over each connecting rod cap bolt before pushing the connecting rod/piston assembly out through the top of the engine with a wooden tool.

Position the piston ring gaps appropriately and use a section of plastic or rubber hose over the connecting rod cap bolts.