Boost guys please help. Piston Rings Boosted application

**noice** · 09-22-2014, 08:32 PM

It is your engine so you can do whatever you want to.

However for a Plama-Moly ring package (can be used for lower boost levels), the molybdenum is sprayed on by a plasma torch and is very good at resisting wear yet porous enough to maintain oil film. With a thin ring pack, you can get away with a finer finish on the cylinder walls. When you bore a block it is like someone taking a plow to a field of dirt, it looks decent to the eye, but in reality it is a bunch of rough v shaped grooves in the material. So the last couple of thousand of the bore is taken out with 240-400 grit honing stones, this would be the equivalent of raking the dirt field, there is still small v grooves in the cylinder. Then depending on the rings that were used, a burnishing brush of hard plastic would be used to further smooth out the cylinder and break the v-shaped grooves into plateau shapes that allow oil to stay in the valleys but allow for a VERY smooth cylinder wall to limit wear.

In an OEM engine you want thin rings for low friction, smooth cylinders for low friction and wear, plasma moly for low wear and plateau machining so the rings can properly operate since they don't require a break in period. For racing the same applies for N/A motors, however nitrous can and will burn the plasma moly coating off. Extreme temperature from boost can do it too. So you end up having to run a steel top ring that can resist this heat. Steel rings need a rougher surface on the cylinder wall as they have to seat in. They also need a larger gap to allow for more expansion from heat.

Basically follow the ring and piston manufacturer's advice, they give you all the specs that you need to follow.

**shownomercy** · 09-22-2014, 08:38 PM

Case in point... mid boost level and a moly coated ring.

Oops

**1QUICKZ28** · 09-22-2014, 08:59 PM

Wow did I just learn a lot. I knew they bored, honed and finished honed but didn't realize that there was different grits and cross hatch for different applications. Great info guys!!

Block has Been previously bored. Had flat tops -5cc. Swapping pistons and rings for boost.

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