Thread: Too much crankcase pressure, novice engine builder

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That was my thought as well, which is why I'm here. You only notice the pressure build up at 6000+ rpm. There really are no problems as far as I can tell below that. I made sure to double check that my ring gaps were correct (both in terms of gap and shape of the gap) and installed the correct way (they were staggered). I recorded myself building this engine and from what I can tell from the footage, it all looks correct.

As for piston to cylinder wall clearance, I know it's not ideal but I'm confident it's in spec. I bought the block when it was bored 30 over. Because I'm working on a tight budget and I already had pistons that were meant for a bore of 30 over. I only had a machine shop do a cylinder hone and no more bore. As a result, the block isn't 100% perfect, but it's still good. I don't have the numbers written down unfortunately, but I know I checked them when I had everything apart.

Static compression ratio is 10.1:1 Results of a cylinder compression test are as follows:
cyl1 - 135 psi
cyl2 - 130 psi
cyl3 - 139 psi
cyl4 - 132 psi
cyl5 - 133 psi
cyl6 - 137 psi
cyl7 - 125 psi
cyl8 - 143 psi

In my inexperienced opinion and what I can tell from googling, these numbers seem fine which would mean the break in process was successful, correct me if I'm wrong.