There’s a lot of hype, speculation and rumors surrounding the 2018 Corvette lineup. Previous, leaked documents, in particular, showed a 6.2-liter LT5 V8 engine coming to the vehicle for the 2018 model year, which begins this summer. Not only that, but the LT5 is supposedly a dual overhead cam design.
Autoblog has put its detective face on and connected a few dots to try and solve the DOHC Corvette mystery, and there’s one very interesting piece. And here it is: the LT5 DOHC V8 engine may be testing in marine applications as you read this.
LT5-powered boats? It does make sense.
Mercury Marine showcased its own LS7 V8 engine-based DOHC engine at the 2016 SEMA Show in Las Vegas. Specifically, Mercury Racing was responsible for ditching GM’s valvetrain setup and placing its own 32-valve DOHC unit in. Why is this important? Mercury Marine was tapped to build the original LT5 DOHC V8 engine for the C4 Corvette ZR-1. That engine was designed by Lotus Engineering, but it was birthed from a boat engine assembly line.
The LS7-based DOHC engine Mercury Racing showed is capable producing 750 horsepower and features an 8,000 RPM redline. Not bad performance figures for a boat, let alone a car. The engine would also have no issues clearing the hood of a Corvette. As the report states, the 6.2-liter LS3 V8 engine measures 17.72 inches tall and fit snuggly under the hoods of Camaro, Corvettes and the SS sedan. This small-block, pushrod V8-based DOHC engine measures just 17.1 inches tall.
The new LT5 V8 engine may not be an all-new engine either since it’s expected the LT5 will debut with the C7 Corvette ZR1, also lending itself to having pushrod roots. Though, we still have our doubts of the C7 ZR1 featuring the engine. It’s still very possible the LT5 will be reserved for the mid-engine, C8 Corvette.
But, then we’re left wondering what the leaked documents represent when stating an LT5 is inbound for the 2018 model year of Corvette. And we seriously, seriously doubt the mid-engine Corvette is coming for 2018. Intel also suggests the base C8 Corvette will not be a hybrid, either, though a hybrid variant is likely, judging by E-Ray trademark filings.
It’s still a tricky puzzle, and one we ultimately won’t know until someone slips and offers more insight into the whole shebang. Ultimately, we won’t know the outcome until the Corvette team is ready to show the C7 ZR1 to the world.
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The LT5 DOHC motor used in the 1990 - 1995 Corvette ZR-1 - was NOT "birthed from boating". The engine was designed and engineered by Lotus in Hethel, England (GM owned at the time), AND GM Powertrain. Mercury Marine, which was owned by GM at the time, was used to manufacture the engine, because Mercury Marine had the experience at building low production, all aluminum engines which GM Powertrain did not.
* correct but Mercury Marine was not owned by GM at any point
Mercury Marine was and is part of the Brunswick Corporation. GM never owned them.
And GM had zero to do with the LT5 project, other than demanding it must remain on 4.4" bore centers. Which made zero sense because it shared nothing else with any other GM engine.
GM had everything to do with it. It was designed completely in house. And it did share something with the small block. They both use the same rod bearings.
I stand corrected on the ownership of Mercury Marine.
What Mark said ^^^
Do your research Sean. I know you want to be first with a story but accuracy is just as important.
I didn't mean to portray the engine to be born from boating in the outright sense, merely that it was assembled by Mercury Marine. I've updated the story for clarification.
Thanks for reading as always,
-Sean
It will need forced induction to make that kind of power in a boat, Marine Engines don't spin 8 grand for long.
This small-block, pushrod V8-based DOHC .....is that right or possible?
This small-block, pushrod V8-based DOHC engine measures just 17.1 inches tall.
This engine will use some sort of timing chain instead of pushrods, if it is DHOC
That's what an OHC engine usually has.
Pushrods belong in the cro-magnon knuckle dragging era. Lol
I am not sure why it seems hard to believe Chevy can't make a DOHC engine. Ford has been doing it for years. Also why is it hard for Chevy to build a mid engine Corvette, several car companies have built mid engine cars. Chevy just needs to do it right. Mercury Marine has a DOHC LS based engine already on the market, pretty simple mods to get the DOHC. They can be turbocharged to over 1000 HP. Chevy needs to look at the failures with the Fiero, the missteps bringing back the GTO, and many other cars that promised performance but didn't deliver. If the mid engine corvette doesn't perform it will fail
Chevy (GM) can build a reliable DOHC engine (Cadillac Northstar), not to mention the high feature V6 in cars and trucks. What makes the Corvette so unique in today's vast market of turbocharged and DOHC engines is the fact that a pushrod, 2 valve per cylinder engine can produce over a horsepower per pound of engine weight (LS7) while achieving a lower BSFC (Brake Specific Fuel Consumption) value which results in the most efficient larger engines on the road. Compare the latest 5.0 Coyote (Mustang) to the 6.2 LT1 (Camaro) fuel economy. There are other factors at play but that is a pretty good comparison. A final note, unless the deck height of this latest rumored engine is substantially less than 9.24" (current small blocks), a DOHC cylinder head will be inches taller than a pushrod cylinder head given a common cylinder bore. I do not agree this will fit under the hood of a traditional Corvette but that is not a show stopper either (2009-2013 ZR-1). For a given displacement, a pushrod engine will have a lower center of gravity, more compact overall dimensions, and almost always is lighter (comparing alike materials).