What is up engine heads! It's finally time for the one and only GM LS engine!
D4A merch: teespring.com/en-GB/d4a-merch
Patreon: / d4a
In 1676 Sir Isaac Newton wrote this in one of his letters „If I have seen further it is by standing on the shoulders of giants“. If there was ever an engine that this quote applied to, it's got to be the LS engine. Because the GM LS is the direct descendant and the modernized and improved version of one of the most Iconic engine designs ever made the Small block Chevrolet engine. The timeless original small block design was on the market for almost half a century and during that time it managed to set itself apart by being a class leader in many aspects. But by the 90s the small block Chevy finally started to show it's age. It was time for a successor. So GM introduced the Generation II of small block engines, but unfortunately without much success. The Generation II was largely based on the original small block, and just like the small block it started to struggle with the strict emissions, mpg and weight regulations of the 90s. So by the mid 90s GM decided that it was time for a clean sheet design. A brand new V8 engine. But the generation III and IV of the GM small block could have turned out very differently, because in the 90s everyone was talking about DOCH, V6 that, inline 4 this and even within GM there was this feeling present that the pushrod is a dinosaur with no future. But GM wasn't quite ready to give up their push-rod so to decide the future of the engine GM carried out some blind testing using their own executives which ended with the conclusion that the entire GM leadership preferred the pushrod engine. After driving two otherwise identical C4 corvettes, one with a pushrod LT4 and the other with the Lotus designed DOCH LT5 engine the management decided that the pushrod was staying.
But the other important thing done by GM after the blind testing is that they appointed the right person for the job. They didn't import engineers, but relied on one of their own veterans, Ed Koerner. A veteran of engine design but also a true car enthusiast, a drag racer and record holder himself. If you want an engine that will be loved by petrolheads, you better get a petrol-head to design it.
The GM LS engine premiered in the form of the LS1 engine in 1997 in the engine bay of the C5 Corvette. It made impact right after it's launch and won Ward's engine of the year award in the same year. In the following years the LS family would spawn several truck engines such as the LM, LR, LY, LQ, some of which make great starting points for projects. The generation IV of the small block started in 2005 with the LS2 and improved many aspects of the engine including the intake and exhaust and brought new technologies such as displacement on demand and variable valve timing. 2006 brought the Z06 C6 corvette and the 7 liter behemoth LS7 engine, which was soon up followed up by the LS3, perhaps the most popular LS swap engine. After this the horsepower monsters, the supercharged LS9 and LSA powered the Cadillac CTS-V, the ZL1 Camaro and the ZR1 Corvette and came as the final hurrah of the LS which would finally end it's production in 2017. Something that was heralded already in 2014 by the C7 corvette and it's LT1 engine.
When it comes to the specs all LS engines have 90 degrees opposed cylinder banks and a deep skirted Y shaped engine block which is a massive improvement in strength over the original small block chevy block design. The deep skirted block also enabled engineers to design 6 bolt cross bolted main bearings caps. The block also accommodates some very long held bolts for minimized bore distortion. All LS engines have forged powdered metal connecting rods with fracture split caps. An exception to this are the LS7 and LS9 engines which feature some very fancy titanium connecting rods. The heads feature hydraulic valve lifters and some very nice lifter guides that make it possible to swap cams on the LS engine without removing the heads.
When it comes to tuning, the LS engine family is a true champion because it has a lot of things going for it, it's readily available, reliable and has an amazing aftermarket. The block is strong and can take a lot of boost. If you want massive power the only thing your really have to get rid of are the stock cast pistons and powdered metal rods, after which the LS engine can take you to the stratosphere. The stock crankshaft, even though it's cast nodular iron, is very strong and can take 1000 hp like a champ. When it comes to the camshafts, many stock LS camshafts are pretty well suited for boost, except when aiming for obscene power. NA tuning the LS on the other hand starts with cams, intake and exhaust and some remaps.
A very special thank you to my Patron:
Daniel
driving 4 answers is part of the Amazon Associates program.
#d4a #iconicengines #lsallthethings