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Pros and Cons of the LS engine.

Posted by Jeff Behuniak on Jul 6, 2017 12:00:39 PM

Over the last 10 years the LS engine has rose to prominence.  The engine's performance potential and tight package along with high engine availability has created the perfect storm for the automotive aftermarket. Crazy swaps have pushed the LS into a level of its own. Chevy LS engines have found their way into everything from Classic muscles cars to lightweight sports cars like the Miata. This potential has even caused some series to ban LS swaps...

As with anything there are pros and cons. Despite the popularity of the LS engine there are a few drawbacks to the engine platform. We've assembled a list of pros and cons to the platform to help you in your approach to the LS engine.

In terms of the engineering of the LS platform, there many pros that make it a strong engine.  In addition to those engineered in benefits, we see these other factors as big positives.

  • Strength of the block;
  • Price & Availability;
    • Introduced in 1997 the LS and its various iterations have found their way into over 50 cars throughout the years. The LS was used in everything from sports cars to trucks which has created a buyers market in junkyards across the US.
  • Size & Weight;
    • There are some distinct disadvantages to the push rod design of the LS engine. However, many feel the packaging and weight savings that it offers can outweigh those disadvantages.
  • Aftermarket Support;
    • A very good metric of a platform is how readily the aftermarket supports it. This has been seen since the early days of hot rodding. From the SBC to the Ford Mustang, the aftermarket will support great platforms. Theses days parts for the LS engine are just as readily available as the blocks themselves. (Summit lists 86,000+ that come up in a Chevy LS parts search)

The LS engine is not without its issues though. For an engine that is touted as such a performance oriented engine the LS has some shortcomings.

  • Oiling System;
    •  Piston Ring Seals
      • Some LS variants have been plagued with bad piston ring seals. This issue can cause oil consumption issues. As this issue gets worse it can also create an increasing amount of blow by in the engine. 
    • Oil Pump Cavitation
    • Non-Priority Main Oiling (OEM Blocks)
      • A common upgrade on aftermarket blocks is priority oiling. Priority main oiling ensures that oil goes to the mains first and to the heads as a secondary path. This ensures that oil pressure drops have a minimized effect. A stock LS block does not feature priority main oiling. In an OEM setting priority main oiling makes less sense because the engines are expected to spend very little time at high rpm.
  • Engineering;
    • Skirted Block
      • While the skirted block design strengthens the block it does limit the ability to reduce windage through traditional methods. The use of crank scrapers and power pouches is completely removed and the effectiveness of windage trays are reduced.
    • Drivetrain
      • While the push rod design is great for the packaging and is one of the primary reasons it is so popular in engine swaps. The valve train in a push rod engine is a limiting factor. The complexity of the valve train creates limitations on the RPM range possible. 
      • A push rod motor also requires more valve train parts when compared to an OHC engine. This creates more opportunity for parts to fail along with increasing the friction created in the valve train as there are more moving parts.
      • Another basic issue with the LS and all push rod motors it the limitations of the actual valves that can be used. The push rod engine is limited to one intake and one exhaust valve which can limit the volumetric efficiency. The OHC engine has featured up to 5 valves per cylinder to increase it's performance capabilities.
    • Maintenance
      • Due to the packaging of the push rod design the camshaft is located in a difficult to get to location. When replacing the camshaft in an LS you will commonaly need to either remove the engine or the radiator to be able to access it.
  • Other
    • Variations in LS versions from GM
      • Since the LS engine was used in a variety of platforms and for a variety of uses there is a plethora of variants of the engine. Everything from the heavy iron truck block through the lightweight aluminum performance LS7 has differences that should be understood and accounted for in each build. With all the variations it can be difficult to understand exactly which iteration you have and how it needs to be built for you goals.

The Ultimate LS Wet Sump System

Topics: Reviews & Comparisons, Engine Oil System Technology

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