LS3 Engine Engineers - Inside Information

In a VETTE exclusive, we introduce you to the engineers in charge of the Corvette's LS3 engine components. Part 1: Cylinder block, rotating assembly, and oiling system

Christopher R. Phillip Apr 1, 2011 0 Comment(s)
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Crankshaft
Name: Paul Gelazin
Title: Design Responsible Engineer
Years with GM: 26

Vemp 1105 04 LS3 Engine 2/9

Other experience: 18 years as an Engine Structural Analysis Engineer

What LS3 part(s) are you responsible for? Crank, bearings, damper, flexplate, engine balancer

What LS7 and LS9 parts are you responsible for? Same

What other Corvette parts have you been involved with in the past? All Gen III and IV rotating cranktrain components (crank, bearings, damper, flexplate, and flywheel).

Why do you think your LS3 part is the most important part on the engine? The crank is the main component that takes the unnatural reciprocating events and transfers them into rotational power. The design has to be robust enough to handle all the punishment that eight power cells (piston, pin, and rod), working to create 430 hp, can throw at it under a multitude of speeds and conditions.

What is a focus area you watch when designing the LS3 part, especially knowing it is for a Corvette engine? Crank structural integrity is foremost. There was an additional focus on fatigue strength enhancements to meet durability requirements, since the LS3 is the most demanding application for the iron crank. This strength is created by inducing compressive residual stresses in the undercuts (the area where the journals meet the side of the crank throws) with rolling loads in the range of 6,000-7,000 newtons. This process significantly improves the fatigue strength in the critical sections of the main and rod journals.

Vemp 1105 05 LS3 Engine 3/9

For the LS3 dry-sump application, a steel crank is used and is actually machined from the LS9 forging. It is also an undercut and rolled design, and can handle anything you can throw at it in the Grand Sport.

What are the current trends with your LS3 part? Where is it going? The latest focus has been on robustness enhancements in the journal-bearing system. We're always looking at improved bearing materials and coatings to provide an added level of protection against extreme operating conditions.

Compare your part to aftermarket parts of the same item. What makes yours better? The LS3 cranktrain has a significant amount of analytical input guiding the design. We have many requirements with regards to torsional response, bearing loads, oil-film thickness, bending deflections, mass, and strength. While the aftermarket may enhance a certain aspect, we use the analytical tools to design a crank that meets all the requirements for a better overall engine package.

Do you own a Corvette, a classic car, or have a related hobby? My interest has been airplanes since I was a kid, so I have more wrench time on airplane engines than car engines. I have a TCM IO-520L, which is a 520ci Opposed Six that produces 300 hp at 2,850 rpm. It's in a six-place Cessna 210M that we use like the family Suburban.

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