Quote:
Originally Posted by Richey
draw , you should follow PeteKz's advice for a deck height of .75 to 1 mm for better squish and chamber turbulence . Machine the piston tops instead of adding cylinder base shims . From my experience this is a difference you can notice when driving .
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Thanks for the comment, I appreciate it!
Here's where my lack of engine building experience definitely shows. I've spent a lot of time juggling the different options, and I think I've settled on using a 1.25mm shim, which puts my calculated deck height at 1.04mm. Pretty close to the 1.0mm standard spec. I've chosen this as a tradeoff to keep my compression ratio (about 10.1, calculated) in a decent range for street use with 91 octane premium gas and twin plugs. If I was more experienced, I would feel more comfortable with stacking shims of varying thicknesses to reduce the deck height a little. I did seriously consider stacking a 1.0mm and a 0.20mm shim, which would put my deck height at 0.99mm, resulting in a compression ratio of 10.15. But I'm concerned that stacking these two shims would lead to a leak. Also, I'm running the LN cylinders without a head gasket/sealing ring and I'm trying to keep everything as stable as possible.
Anyone with experience stacking shims care to chime in?