When machining threads on a lathe, a "Fishtail" is used to "square" the tool to the part. For external threads, the Fishtail's long edges are held against the O.D. of the part, while the tool is aligned to fit in one of the Fishtail's "V" notches.  When cutting...

This one may be a little obvious, but maybe not. When checking piston-to-valve clearance, use cold clay and roll the engine over. Then, cut it right down the middle with a razor blade to expose your clearance reference. It’s really easy and accurate to measure right...

LS PISTON PIN SIZE Stock GM LS full floating connecting rods use a .943" pin and stock LS press rods use a .945" pin. Some aftermarket forged pistons designed to use a stock LS 6.098" length rods come with the .945" pin type. Pistons can be used as "Pressed" or...

GRINDING THE RAILS When grinding the thin steel oil rails on a ring grinder, lay it on a used cast iron second ring and grind them both together. This reduces the chance of the rail biting or fluttering and damaging it. If you’re careful, you can grind the two for...

END GAP ESCAPE PATH   I often feel that people will gap the top oil ring rail improperly. The top oil ring rail needs to have a gap that is the same as the 2nd (scraper) ring above it, at operating temp. Gapping it the same is a safe adjustment. The tapered second...

FITTING IN A SIZE SMALLER After file fitting piston rings to get the perfect end gaps, we need to remove all burrs left from the filing process. Despite all our best efforts, sometimes we install a ring on the piston and still notice a little drag when testing for...