Super tuning car runs good shooting for great

A cold LD test will however tell you a lot about how well the valves are sealing. When I see numbers so small I'm not even sure I'm seeing anything at all on that little tiny gauge, then I'm a happy camper cuz I know this engine is either gonna fly, or tear off the top of the piston.I'm always hoping the piston hangs together,lol. I like numbers down around 4%;2% is better, but harder to achieve. A needle width is maybe pushing things but I have seen that on certain 2-cycle engines.A bit scary,but it ran hairy,scary,fast.
Since I used to build a lot of small engines, I had to LD them cold, and the results went straight onto the work-order, where a bunch of other info also was recorded. If a particular engine was to come back, I was gonna be prepared. I remember one engine in like 20years coming back.And the customer pointing the finger at me. I calmly dug out the WO, and reviewed the stats.Hmmmm, it says here, and I showed him the numbers.And the factory numbers. Oh....... So When I tore it apart, it became clear,water had gone thru it. It had nothing to do with me. The customer paid, his bill.And came back.Everybody was happy.Especially my boss. And when the boss is happy, everybody is happy. It turns out snowmobiles are real sensitive to water going thru them at 7000rpm under full load. And it happens all the time. I re-built a lot of those,lol.