Pistons

[mavereq]

I got the pistons in today. Thanks for the fast shipping. The piston spec sheet rubbed on the pistons so some of the numbers are hard to read. I can't tell what it said in the bottom right box labeled "gauge point"

[Stinger]

It's actually a value that is used by CP and trying to measure them yourself to determine piston wall clearance will cause more problems than they solve as the heat from your hands will change the piston size enough to negatively effect piston diameter readings.

So you just have the block bored to 3.800" final bore size after all honing is complete, verify ring gap, and you're done. Letting a machine shop set the gap as if they are "normal" forged pistons will result in too much clearance and you'll get piston slap. It's preferred that you don't even give them your pistons, that way they aren't tempted to think they know more about it than CP does.

Honing procedure and ring gap info is here: www.stinger-performance.com/Pics/cp_instructionsheet.pdf

[mavereq]

I have the instruction sheet. Final bore of 3.800" after final honing is what I needed to hear.

[mavereq]

Pistons are beautiful BTW.

[Stinger]

Yes, they are!

[mavereq]

For anyone else reading this:

I shopped around on the pistons. I initially found some other vendors had pistons listed for a little cheaper. Then I noticed that they didn't come with rings. These ended up being about the same price. Don't order the wiseco 2.3 pistons. The dish covers the majority of the piston, which means they have no quench area.

[Stinger]

Yeah, that whole rings/no rings thing gets people. They think Wiseco or Diamond is cheaper but they really aren't after you add up the total cost with rings, and shipping for pistons & rings, etc.

The quench issue is also very important.

[mavereq]

I decided to stick with a cast iron head on this project and save the aluminum head for the drag car. I'm cleaning up an n/a head. I think these pistons are going to work well with it.

[Stinger]

Yeah, they should. Make sure you smooth out that pointy area in the chamber between the valves to change it over closer to a D shape. Just don't go too deep.

[mavereq]

Tim sent me a pic as a guide. He told me to keep the heart shape. This still needs a little work.

[mavereq]

The thing I'm on the fence about is rods. I'm not sure if I should buy some crower sportsman rods. I'm not planning on huge horsepower, but I will be trying to build boost at lower RPMs than normal.

[Stinger]

Yeah, the heart shape is fine, it's just the sharp machined edge in the stock chamber that has to go...it's a prime hot spot to cause detonation.

If you're staying under 350hp and using pump gas, you shouldn't be able to get away with enough cylinder pressure down low (octane limited) to damage the stock rods. Of course getting too aggressive with the tune and rattling it hard could be all it takes though if you've got 20psi at 2500rpm or something though. That's harder on rods than 425hp at 7000rpm.

[mavereq]

I really don't think I'll need to run really high boost. Of course, that's easy to say now.

[mavereq]

Main bearings were toast

[Stinger]

That's ugly