Grand Sport LS3 Crankshafts

[AlHewitt]

I just finished reading the December 2012 Vette magazine - part 2 article on Power Rotation (pages 70). This was an overview of GM's Defiance, OH casting operation where crankshafts are manufactured. Pretty impressive when a factory makes 1,000 crankshafts per hour! All of these crankshafts appear to be castings. The final caption of this article talks about the crankshafts being then sent to GM's St. Catharine’s operation to be assembled into the waiting LS3 engines and then shipped to Bowling Green...

My 2010 LS3 engine (GS with the 6 speed manual transmission) was assembled in Wixom, MI and has the assembler's name attached to it and it has the dry-sump system. Wixom is where the LS7 (Z06) and LS9 (ZR1) are also assembled - so I'm told. The Vette article makes no mention about the crankshafts for the LS3 assembled at Wixom and my question to this group is what type of a crankshaft do I have? Is it a cast iron crankshaft as non-dry-sump LS3's have or is it a forged crankshaft as the LS7 & LS9 have with the dry-sump? LS3's with the dry-sumps have a different crankshaft as the oil pump is located toward the front of the engine - again so I'm told, and could it be that GM uses the same manufacturing process as for forged crankshaft as found in the LS7 & LS9 engines for the LS3?

Elsewhere in this Vette magazine there is a story about a gentlemen who has an LS3 (2008) with a non-dry-sump system making 900HP. He is concerned about the rotating assembly and will be installing a forged crankshaft sometime in the future. If the car was a GS (2010 and later) with a manual transmission would it have come with a forged crankshaft - is my question? Maybe someone knows.
Thanks
Al

 

[Hib Halverson]

LS3 dry sump crankshafts are forged steel, specifically a 44MNSIVS6 steel. LS3 dry sump cranks have a longer snout required to drive the, longer, two-stage oil pump. All Gen 3/4 engines have a front-mounted, crank-driven oil pump, but the dry sump pump is twice as long thus, to drive it, the crank snout needs to be longer.

The LS3 dry sump, LS7 and LS9 crank supplier is SMI Crankshaft in Fostoria, Ohio. Cranks are made there then shipped to the Performance Build Center in Wixom where the LS3 DS motors are built.

Only GS coupes with manuals and Z52 get LS3 dry sump motors.

 

[AlHewitt]

Thanks Hib

I enjoyed reading your article detailing the LS3 albeit written back in 2007 when the LS3 debuted. It appears that some changes have occurred to this engine with the GS/manual offering - not noticeable from appearance but reassuring to know that it can support a lot more HP than 436... Are you aware of any other changes to the LS3 when used in the GS/manual? For example are the rods made of titanium as are those found in the LS7?
Again thanks for contributing.
Al

 

[Hib Halverson]

I enjoyed reading your article detailing the LS3 albeit written back in 2007 when the LS3 debuted. It appears that some changes have occurred to this engine with the GS/manual offering - not noticeable from appearance but reassuring to know that it can support a lot more HP than 436... Are you aware of any other changes to the LS3 when used in the GS/manual? For example are the rods made of titanium as are those found in the LS7?
Again thanks for contributing.
Al

No Ti rods in an LS3 dry sump. The connecting rods are powdered metal and forged. That hasn't changed.

Your assumption, just because the crankshaft is forged, the LS3 can support "a lot more HP than 436" may or may not be true depending on how you define durability and exactly how much extra power you mean.

The only other change the LS3 DS gets of which I'm aware is an engine oil cooler. It may also get the trans and axle coolers.

 

[Huskerman]

My 10 GS 6M Z52 has the KPS - Engine Oil Cooler, KNP - Transmission Oil Cooling System and the KNR - Axle Cooling System......so I'm thinking yours does also....

 

[Hib Halverson]

My 10 GS 6M Z52 has the KPS - Engine Oil Cooler, KNP - Transmission Oil Cooling System and the KNR - Axle Cooling System......so I'm thinking yours does also....

I was pretty sure Z52 included all that. My belief is Z52, Z06 and ZR1, now, all use the same coolers which are actually heat exchangers. The rear axle is axle-lube-to-trans-lube and the trans is trans-lube-to-coolant. The engine oil cooler is engine-oil-to-coolant.

Huskerman, is your radiator aluminum core/plastic tank or all aluminum?

 

[Huskerman]

I was pretty sure Z52 included all that. My belief is Z52, Z06 and ZR1, now, all use the same coolers which are actually heat exchangers. The rear axle is axle-lube-to-trans-lube and the trans is trans-lube-to-coolant. The engine oil cooler is engine-oil-to-coolant.

Huskerman, is your radiator aluminum core/plastic tank or all aluminum?

I think aluminum core/plastic tank if I am reading these pics right.......



For Sale OEM Radiator from 2010 Grand Sport Manual - Corvette Forum

 

[Hib Halverson]

I think aluminum core/plastic tank if I am reading these pics right.......

For Sale OEM Radiator from 2010 Grand Sport Manual - Corvette Forum

You mentioned you owned a GS w. Z52. Can you open the hood and look at the radiator and post what you find?

 

[Huskerman]

Ok....after inspecting the radiator.....I found that it looks just like the one in the pics in my other post. Aluminum core and black plastic on the sides. My car was built on 9/22/09 so it is an early version of the GS....if that makes a difference. It was the 1,834th 2010 C6 built. Hope that helps.....

 

[Hib Halverson]

Ok....after inspecting the radiator.....I found that it looks just like the one in the pics in my other post. Aluminum core and black plastic on the sides. My car was built on 9/22/09 so it is an early version of the GS....if that makes a difference. It was the 1,834th 2010 C6 built. Hope that helps.....

It does.

Means my earlier statement about GS Z52s, Z06/07s and ZR1s all using the same cooling is wrong.

Only the Z06/Z07 and the ZR1 use the high-dollar, all aluminum radiator.

Sorry for any confusion that might have cause, folks.

 

[1analguy]

...there is a story about a gentlemen who has an LS3 (2008) with a non-dry-sump system making 900HP. He is concerned about the rotating assembly and will be installing a forged crankshaft sometime in the future...

If I understand correctly, the iron cranks in wet-sump LS3s are, in fact, not conventional grey cast iron at all, but rather cast nodular iron. The difference being that the graphite component in the structure is in the form of spherical nodules rather than the flakes of graphite that are present in conventional grey cast iron. This inhibits the formation of cracks within the structure and provides enhanced durability/ductility when compared to grey cast iron, which tends to be somewhat more brittle. I'm not sure how wide-spread the use of nodular iron cranks is today, but when I dig back into those old cobwebs again, I'm remembering that the Pontiac SD 455 from the early '70s had a nodular crank, as did a whole slew of Ford's high-performance engines from the late 60's-early '70s. As noted in the OP's example above, nodular is pretty tough stuff. It's also cheaper, lighter, and easier to machine than forged steel, which would make it a popular alternative for production engineers who may not have to worry about ridiculous horsepower levels...

 

[Hib Halverson]

All Chevrolet V8s used nodular iron cranks starting from day-one with the 265 in 1955.

Pontiac V8 all had nodular iron cranks. The difference with the SD455 crank was rolled fillet journals vs. the "standard" machining process used on non SD crankshafts.

I doubt that any of Fords OHV V8s used gray iron cranks, ie: nodular iron cranks were not a sign of a high-performance engine, they were used in all engines.