My 79 Triumph Spitfire 1500 enlarge center oil passage to 5/16ths inch

Описание: In this video, my 79 Triumph Spitfire 1500 center oil passage to the crankshaft main journal is drilled to 5/16ths inch (.3125''). This was suggested as the fix to prevent connecting rod journals #2 and #3 from oil starvation at extended high rpm and trashing the bearing's shell. My existing oil passage to the center was already 17/64ths'' (.265625''), only 3/64th'' smaller than the suggested 5/16ths. I was rebuilding the engine, and this was the time to make the fix. Passage #1 was 3.8125'' long, and that's what it needed to be. Passage #2 was 2.1875'' long, only needed to be 2.0625'' for my block. The drill bit I used was 4.5'' long and worked good with my electric hand drill. I marked the dog leg with a marker to help guide me. Watching the bull's eye in the oil hole, I was keeping the new passage lined up with the smaller existing hole. Slow speed to the drill's rpm and slow forward motion. Where the 2 holes meet, I could see the bottom needed a small amount of drilling to smooth out the curve. On the outside, cleaning up the sharp edge of the new hole was done by hand without the drill. Turning a 9/16ths drill bit by hand, I was able to remove some of the soft casting to make a 45-degree opening. I read how to drill out the suggested oil passage. Measured the existing passages, drew myself a diagram, and thought it through. I decided I wanted to do it myself. This video was published to show what I did to my block.