Pistons and rings

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==SBC oil ring depth==
 
==SBC oil ring depth==
GM has used a both a shallow oil ring and a deep oil ring on SBC engines. The difference is enough between them that if a deep oil ring were to be installed on a shallow oil groove piston, that the ring would bottom out in the groove. This leaves a portion of the ring extending out past the piston and will prevent the piston from being installed. The piston can be damaged if it's forced, and if somehow the piston were to be installed in the bore with the wrong oil ring, the bore and piston could be damaged.
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GM has used a both a shallow oil ring and a deep oil ring on SBC engines. Up to 1985 the oil ring/piston groove was 'deep' (0.195" or thereabouts). From about 1986 to the end of the L31 Vortec production, the 'shallow' rings (around 0.165") were used- but there could still be deep groove pistons and rings being used from about '95-back.
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The difference is enough between them that if a deep oil ring were to be installed on a shallow oil groove piston, that the ring would bottom out in the groove. This leaves a portion of the ring extending out past the piston and will prevent the piston from being installed. The piston can be damaged if it's forced, and if somehow the piston were to be installed in the bore with the wrong oil ring, the bore and piston could be damaged.
  
 
Using a shallow ring in a deep groove will function normally, but installing the ring on the piston and the piston into the bore will be a chore due to the oil ring trying to pop out of the groove.
 
Using a shallow ring in a deep groove will function normally, but installing the ring on the piston and the piston into the bore will be a chore due to the oil ring trying to pop out of the groove.
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And if that wasn't enough, there were metric rings (2mm x 1.5mm x 4mm) used from about 1992 to 2002 when the Vortec bowed out. If you have access to the vehicle VIN and the original engine is still there, the metric ring engines are VIN '''P'''.
  
 
===Identifying what rings to use===
 
===Identifying what rings to use===

Revision as of 04:02, 19 December 2012

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