Forged Pistons for Turbo Build

[dag19]

I would like to replace my stock pistons in a 6.0L LQ4 with a set of forged pistons from Summit at the link below. When I replace the pistons on the stock rods, will I have any balancing issues? Is there anything else I should be aware of if I go ahead with this change out? Maybe a better set of pistons to use perhaps?!

https://www.summitracing.com/parts/sum-326945400012

[71cadc10]

really doesn't look too bad.
Says they have forced pin oiling...which is hard to see from the pic looks like there is a hole there. That's a good feature for high hp, hole drilled from the oil ring groove to the pin boss.
your standard Wiseco doesn't have that anymore.

I do think you will need to rebalance the crank, the weight of this piston won't be same as stock.
once you add the rings you're about $600 for a setup. about $100 less than most stuff out there today.

Unless your bore and block are really in good shape, I'd consider having it honed to 4.005 or bored to 4.030 to make sure straight and round. Pistons and balance cost would be the same regardless of what bore size you do.

[dag19]

Thanks that's all good info. As far as boring or honing the block goes, I need to find a good machine shop. Not sure what that might cost but I'm sure it'd be worth it since it's out and accessible. I was hoping to not need to tear it clear down!

[LS short box]

Because I like spending other peoples money maybe a set of forged rods? Scat or Eagle make different price level rods. I've used both companies "H" beam type in some LS engine rebuilds with great success. Times two on the hone/bore depending on the wear. Also I would rebalance as said above.

[AussieinNC]

The engine block will need to be fully disassembled, hot tanked, new cam bearings etc...

Boring and honing is a standard process that any reputable machine shop can accomplish...make sure the shop uses deck torque plates on the block during the process....if the shop doesn't have torque plates,,,,FIND ANOTHER SHOP !

The deck of the block will also need to be surfaced to make sure the deck surfaces are parallel to the crank center line.

[dag19]

Thanks for spending my money Short Box!! I will have to look into what kind of money I'm getting into. Would make it that much stouter for sure.

Thanks Aussie...I'll definitely make sure on the deck torque plates. Good call on the centerline. I'll make sure it's addressed.

Do you guys recommend a custom ground can? Or is there one off the shelf that will work?

[LS short box]

Happy to help spend. The other thing about aftermarket forged rods are that they have "free floating" piston pins meaning they are not pressed into the rod as are the stock rods are. If you go forged rods make sure they work with your new pistons. The piston pin needs to be retained by clips that have grooves machined into the piston. I no problem with Summit products. I've bought thousands of dollars of stuff from them over the years but I would recommend a LS engine shop for parts. Most have very good prices on engine parts.

[Heavymetl]

I mean just get the cheapest 4.8 you can find, Holley EFI, and boost it!

[AZ 67 C10]

What kind of power are you after? How many miles on the motor? There is no real need to do anything to the rotating assembly for a low boost LS. If money is no object then rebuild the whole thing with forged internals and all the other supporting parts. Otherwise a cam, springs and a good tuner will run 600hp all day long

As far as Summit's LS parts go, there is a lot of info over on LS1tech about them. I wouldn't be afraid to run them, seem like quality stuff.

[pcmcobra]

I put those pistons/rings in my ly6(full machine/rebuild), not running yet...

[dag19]

AZ I am lookin for 6-700 HP. Nothing too crazy. Still need to get that thing to hook up. There is just under 200k miles on that Hummer. I intend to run somewhere around 8 - 12 pounds of boost. At least until I get a taste of it and then crank it up!!

Nice glad to hear there are others running those parts. I would assume with technology the way it is....they should be solid.

[americanmusc1e]

Originally Posted by AZ 67 C10

What kind of power are you after? How many miles on the motor? There is no real need to do anything to the rotating assembly for a low boost LS. If money is no object then rebuild the whole thing with forged internals and all the other supporting parts. Otherwise a cam, springs and a good tuner will run 600hp all day long

As far as Summit's LS parts go, there is a lot of info over on LS1tech about them. I wouldn't be afraid to run them, seem like quality stuff.

That's about what I was going to say. The weak parts on Gen3 motors are really the rods. Not the pistons.

I think a lot of people think forged pistons are a must for boost. They pretty much are on old school engines. The fact is, cast pistons are pretty tough, they don't take heat and detonation well though. Because the LS has fairly even cooling and excellent fuel distribution (with MPFI) the pistons usually stay cool and live a long happy life under moderate boost. Go lean and that changes fast though.