Hey guys, I thought this would be the best place to ask some questions about the pistons in my rebuild which are from a 96 Grand Sport (LT4). I should mention firstly, that I'm actually building the engine for my 99 2D Tahoe. I picked up some perfect OEM Grand Sport pistons (with the LT4 cast into the side) and will be using them for my build.

1. Would I need to re-balance my rotating assy.? I'm also using the 'pink' rods with a standard stroke crank.

2. Which rings do I use? I know these have a metric 1.5mm top ring, but not sure about the others. I'm currently considering these:
http://www.summitracing.com/parts/pcr-41497cp

 

Not sure about the rings but you should get the rotating assembly balanced.

 

I'd never pass the opportunity to balance......

thats the longetivity of the engine. Might add a couple bucks to the machine shop tab but you get that back 10 fold in the lifespan of the motor.

 

anytime you start mixing and matching parts, its good to balance (or rebalance) the lower end. I've got an LT4 torn apart, one of the alleged advantages of the powdered rods was consistency in weight, and this must be true because they basically lack a traditional balancing pad on the big end; a few years ago I did a build using "pink" rods and some rods required a bunch of grinding befor the whole rotating assembly was brought into balance.

 

Awesome. I'll get that done then. Still waiting on a response about the rings.

Thanks!

 

Nothing ever wrong with OEM cast pistons. Though not sure if (LT4) these are hypererutic (high silicon content) or not. Hypereuritic (i cant spell) pistons require a larger top ring gap than cast or forgred pistons. Alternatively, kieth black pistons are very good and are stronger than some forged units. Tried Wiseco-tru pistons and got burned. Now I am all Ross forged units.

For rings, i build with the gapless (I perfer the top ring to be gapless rather than the second ring). Gapless does wonders for controlling elimination blow by and improving emissions.

Materials are cast, steel, and ductile. Since this is a non-nitrous, OK compression ratio truck motor...it doesnt matter which material. Some will say cast will seal better, some say ductile will handle more pressure-power.

these are for 1.5mm/1.5mm/4.0mm rings (most stock chevys are 3/16,3/16,3/8? so please check your card)

Total Seal Piston Rings T6434-35 -Piston Rings, Ductile Iron, 4.030 in. Bore, 1.5mm, 1.5mm, 4.0mm Thickness, 8-Cylinder, Set $248.95

Total Seal Piston Rings MS6434-35 - Total Seal MS AP Advanced Profiling Ring Sets Piston Rings, Steel, 4.030 in. Bore, 1.5mm, 1.5mm, 4.0mm Thickness, 8-Cylinder, Set. $376.99


Total Seal Piston Rings S6434-30 - Total Seal TSS Street Piston Rings $196

What compression ration are you trying to get?

Throw those "pink" rods AWAY...get some basic aftermarket I-beam rods from eagle or Scat with ARP bolts for reliability.

Stock crank is OK, but why not stroke it...same price (243) excluding having block clearanced (50-100) and using either stroker rods, small base circle cam, or just lucky. I used a set of eagle rods that were not stroker but cleared the cam without issue. Plus that heavy wieght beast will need torque.