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

It is important before pulling the piston and connecting rod assemblies that you have to first relieve the cylinder head(s), oil pan and finally the oil pump. First ensure that you eliminate the entire top ridge of the cylinder by carefully applying a ridge reaming tool according to the manufacturer's guidelines else the pistons break. After that inclined the engine in upside-down position with the crankshaft at the upward position to remove the cylinder ridges. Prior to disconnecting the connecting rods look at the end clearance using feeler gauges to make sure the the clearance is removed; if the end clearance is beyond the service limit then new connecting rods may be needed. Also, make sure that bolting connecting rods and caps are marked, and if they are not marked, one ought to use a small centre punch to do so. Slowly turn out each of the connecting rod cap nut until they can be unscrewed by the hand, then unbolt the number one connecting rod cap and the bearing insert but be careful not to let the bearing insert fall off. During piston removal, the crankshaft journal and the cylinder wall are very sensitive, slip a short length of plastic or rubber hose over each of the connecting rod cap bolts. The connecting rod/piston assembly should now be pushed out through the top of the engine; the use of the wooden hammer handle can also be of assist when doing the upper bearing insert. If there is such resistance, then check whether all the ridge material has been provided fully. Do this for the remainder of the cylinders, and after their removal, replace the connecting rod caps and bearing inserts into their intended rods, tightening the cap nuts only enough with your fingers so as not to mar the bearings.

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 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.

Prior to fitting of the piston and connecting rod assemblies the cylinder walls should be clean, the top edge of each cylinder should be chamfered and the crank shaft should be fitted. Take off the connecting rod cap of the number one connecting rod and pull out the bearing inserts; there are always some debris on the bearing surface-wipe this area with a clean cloth. Remove any dirt or grease from the back side of new upper bearing half, place the half in its place on the connecting rod so that the tab should fit into the recess and so that you do not hammer the bearing face or nick it, do not lubricate at this time. Remove the bearings on one rod cap and clean the other side of the bearing insert that is on the other rod cap and then you will place the other bearing insert into the rod cap making sure the tab gets into the recess without use of grease.-align the gaps of the piston ring in the right position and place a section of a plastic or rubber hose over the connecting rod cap bolts. Dip the piston and the rings in clean engine oil, place the piston ring compressor on it and center the skirt about 1/4-inch away. Turn the crankshaft through 720 degrees and place the number one connecting rod journal at bottom dead centre and wipe the cylinder walls with engine oil. With your notch on top of the piston facing the front of the engine, carefully install the piston and connecting rod assembly into the number one cylinder bore with bottom of ring compressor lying on the block and tap the top side for better contact. Scrape, deglaze and clean the 'top' of the number one connecting rod journal, on the crankshaft, and the bearing surfaces, in the rod. Ease the piston onto the crankshaft journal with downward pressure on the ring compressor to avoid the piston rings' shooting out through the open upper end of the cylinder; with a wooden hammer handle, gently knock the top of the piston. After the fixture is set, measure the oil clearance of connecting rod bearing by placing a piece of Plastigage at number one connecting rod journal before finally tightening the rod cap permanently in place. Scrub the connecting rod cap bearing face, Remove protectors from the connecting rod bolts and then carefully fit the rod cap in a manner that the marks faced each other. All the nuts to be tightened performed in three steps without having to rotate the crankshaft. Slowly and cautiously undo the rod cap to avoid upsetting the Plastigage and by referring to the width of the crushed Plastigage on the scale on the container get the oil clearance that should conform to the specifications. Remove as much Plastigage material from the bearing without damaging the bearing itself, clean both bearing faces, using a finger or paper towel applied a thin film of clean engine assembly lube. Put the connecting rod back to its position, take off the protective hoses, fix the rod cap and tighten the nuts in three sequences. Do the same for the piston and connecting rod assemblies that are yet to be cleaned; also make sure that the pistons are in the right position. Once all the assemblies are in place take the crank by the aid of a breaker bar, turn the crankshaft to feel for binding, and at last check the connecting rod end float, match them up to the standard provided for correctness.

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.

A piston ring installation tool should be used to carefully remove the rings from the pistons, ensuring that they are not nicked or gouged.

Ensuring they are clean and removing the original piston rings from the pistons.

Ensure the cylinder walls are clean, the top edge of each cylinder bore is chamfered, and the crankshaft is in place.

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.

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.