High compression motor build questions

[blykins]

Originally Posted by Hotfingrs

Just ran my figures and have a static of 11-1 and dynamic of 8.59

I'd do it on an engine that I'd build for myself...or a race engine, but I wouldn't build one that tight for a customer. It can work and often does, but it would be more of a worry than a benefit for an engine builder. The amount of horsepower that you gain by an extra 1/2 point of static compression really doesn't outweigh the risks. The customer could always install the engine in a 5000 lb car that runs uphill at 1500 rpm all the time in 100° weather.

For a regular street engine, I usually aim for 10-10.5 and don't have any problems with that and the camshafts that I run.

Block prep/piston prep/good machining also eliminates a lot of issues with the higher compression ratios. Eliminating all sharp edges on the pistons, running a tight quench, and running efficient chambers helps a ton. I always try to run about .040" quench on the engines that I build. That means that the block gets machined so that the pistons are sitting at zero deck.