GM Camaro 1967-1981 Repair Guide

Pistons and Connecting Rods

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REMOVAL & INSTALLATION



See Figures 1 through 16

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Fig. Fig. 1: Check the ring end-gap by squaring it in the cylinder bore with an inverted piston, then using a feeler gauge



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Fig. Fig. 2: Ring gap location for all engines with the exception of the 231 cid V6 engine



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Fig. Fig. 3: Ring gap location for the 231 cid V6 engine



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Fig. Fig. 4: Piston-to-connecting rod relationship for 230 and 250 cid (inline) engines



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Fig. Fig. 5: Piston-to-connecting rod relationship for small block V8 and V6 engines



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Fig. Fig. 6: Piston-to-connecting rod relationship for big block (Mark IV) V8 engines



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Fig. Fig. 7: Place rubber hose over the connecting rod studs to protect the crank and bores from damage



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Fig. Fig. 8: Carefully tap the piston out of the bore using a wooden dowel



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Fig. Fig. 9: Use a ring expander tool to remove the piston rings



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Fig. Fig. 10: Clean the piston grooves using a ring groove cleaner



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Fig. Fig. 11: You can use a piece of an old ring to clean the piston grooves, BUT be careful, the ring is sharp



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Fig. Fig. 12: Checking the ring-to-ring groove clearance



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Fig. Fig. 13: The notch on the the side of the bearing cap matches the groove on the bearing insert



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Fig. Fig. 14: Most rings are marked to show which side should face upward



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Fig. Fig. 15: Most pistons are marked to indicate positioning in the engine (usually a mark means the side facing front)



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Fig. Fig. 16: Installing the piston into the block using a ring compressor and the handle of a hammer

  1. Drain the crankcase and remove the oil pan. Remove the oil pump as described later in this section.
  2.  
  3. Drain the cooling system and remove the cylinder heads.
  4.  
  5. Remove any ridge or deposits from the upper end of the cylinder bores with a ridge reamer. Do this with the piston in the Bottom Dead Center (BDC) position and a clean rag on top of the piston to collect cuttings.
  6.  
  7. Check the rods and pistons for identification numbers and, if necessary, number them.
  8.  
  9. Remove the connecting rod cap nuts and caps. Push the rods away from the crankshaft and install the caps and nuts loosely to their respective rods.
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  11. Push the piston and rod assemblies up and out of the cylinders.
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  13. Before replacing the rings, inspect the cylinder bores. If the cylinder bore is in satisfactory condition, place each ring in its bore in turn and square it in the bore with the head of the piston. Measure the ring end-gap. If the gap is greater than the limit, get a new ring. If the gap is less than the limit, file the end of the ring to obtain the correct gap.
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  15. Check the ring side-clearance by installing the rings on the piston, and inserting a feeler gauge of the correct dimension between the ring and the lower land. The gauge should slide freely around the circumference of the ring without binding. Any wear will form a step on the lower land. Replace any pistons having high steps. Before checking the ring side-clearance be sure the ring grooves are clean and free of carbon, sludge, or grit.
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  17. Install piston rings with a ring expander. Compression rings have a mark which must face the top of the piston. The top ring is chrome or molybdenum faced. When installing oil rings, do the following: first, install the oil ring in the ring groove and insert the anti-rotation tang into the oil hole; then, holding the ends of the spacer so they butt up against one another, install the lower steel oil ring rail; repeat this procedure to install the upper rail so that the gap will line up with that of the lower rail; flex the oil ring assembly to make sure it is free-if it binds, the ring groove must be dressed at a narrow point, or a distorted ring must be replaced; install the lower compression ring with its gap 120 degrees (one third of a circle) away from oil ring gap; install the top ring with its gap 120 degrees away from that of the second ring. Be sure to install the piston in its original bore. Install the piston and rod assembly with the connecting rod bearing tang slots on the side opposite the camshaft on V8 engines. Inline engine pistons must have the piston notch facing the front of the engine. Install short lengths of rubber tubing over the connecting rod bolts to prevent damage to the rod journals. Lubricate pistons and rod bearings with light engine oil. Install a ring compressor over the rings on the piston. Lower the piston and rod assembly into the bore until the ring compressor contacts the block. Using the wooden handle of a hammer, push the piston into the bore while guiding the rod onto the journal.
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