This is part 1 of many in Limitless’ engine build. – be sure to check out the rest of the posts there. Quick foreword – the engine in the pic was my “old” engine. There’s a long history behind that, but the entire thing was effectively bought, and re sold, over the course of the past two years. I figured it was a relatively ironic way to start off the “plan everything” post…but it’s a different story for a different time!
Education is Key!
So you want to build an engine! After researching for endless hours on the internet, one thing seems to get beaten into your head…every part is important, and they all have to work together. The whole engine has to be planned ahead of buying even one thing, because all the parts have to work together. You need to ensure that every component you’ve selected is the right one for the job, that it fits the puzzle just right, and that it’s the best selection for the overall goal…because all the parts have to work together.
The thing is, it’s true. You really do need to have everything selected and figured out before you start buying! Every single aspect of the engine affects every single other aspect. A cam choice will influence your dynamic compression, which will therefore in turn affect your cylinder head choice, and your piston choice, which themselves influence your valve train and cam and block, which all influence your cam choice…etc etc etc. That means you really have to actually know about every aspect of the engine, to correctly pick even one aspect. Education is key.
I’ve learned as much as I have from a huge number of resources over the past 3-4 years…forums, books, youtube, and friends have all been immensely helpful. In no particular order, here are some of the resources I’ve consulted through the years – keep in mind that this list only represents ~25%, but these were the ones that stood out. Keep in mind also that as I’ve learned more, I’ve learned that I have to take all of them with a grain of salt. Engine building seems to be one of those things that is actually science, but has a huge, huge amount of subjective opinion taken as truth – frequently incorrectly, and often repeated!
Forums:
- Glen-L
- Offshore Only
- Socal Jetboats
- Chevelles.com
Websites:
- Summit / Jegs (seriously they have a few super basic fundamental things that aren’t listed anywhere else…plus the reviews / questions on various parts you want to order are worth a lot!)
- chevydiy.com
- The various manufacturer’s websites like AFR, Comp, Scat, etc
Youtube:
- Pete’s Garage
- The Horsepower Monster
- Engine Masters
Books:
- David Vizard’s Chevy Big Blocks: How to Build Max Performance on a Budget
Plan YOUR Build, Not Someone Else’s
There are a million engines our there, for a million different people. Chances are good that what you need, and what someone else has done – what anyone else has done – are not the same. It gets to the point that certain choices, specs, etc that are the only correct answer in one – or even most – applications, are actually wrong in your application. That’s why in the resources above, you’ll notice there were quite a few marine specific resources…because I’m building a boat engine. There’s even a jet boat resource, because I’m building a boat engine for a jet boat. But you have to know which aspects are worth taking for each. For instance, the jet boat community seems to have a fundamental objection to anything that isn’t as simple, loud, and powerful as possible…and that’s just not what I want. So whereas they’ll say to run open headers, no thermostat, etc…that doesn’t work for me. And therefore my component choices and my build will be different than theirs. On the flip side, jet boats have an extremely unique power requirement that neither cars nor regular boat engines have in common…so that was really important to pay attention to. And most importantly, I couldn’t just buy an off the shelf Mercruiser or GM crate engine – as neither would meet my specific needs, even though they’d both get equally close.
In my case, I made a few basic selections…some of which were driven by necessity, and others by personal preference. The “high level” build I decided on was a naturally aspirated, fuel injected Big Block Chevy. I was targeting a mild performance build (which admittedly turned into a bit more of a high performance brick shit house build), for a jet boat’s power requirements; but more in line of the high end (non jet) marine philosophy, using stuff like oil coolers and thermostats and water cooled exhaust. Most importantly, while I wanted some pretty serious power, I mostly wanted the thing to last forever. And while cost is always a factor, Limitless has taken 12 years of my life and the majority of my disposable income to date…so while I wasn’t going to spend needlessly, I wasn’t going to cheap out either. This initial selection meant that I could really narrow my research – I don’t need to know about a 2JZ, or a 351 Windsor, or anything to do with forced induction or drag racing or regular daily drivers. This helped a lot, since even with all of that narrowing down, it still took literal years to learn enough to proceed confidently!
Ultimately, it’s really important that you’re honest with yourself on what your goals are – beyond the “Good, cheap, fast – pick 2”. You can build the worlds greatest drag engine, but if you stick it in a boat, it just won’t work or last. There’s a ton of things to consider around parts availability, cost, knowledge base, and suitability to your project. While I’ve seen a cummins powered jet boat, and a twin turbo hemi jet boat, and an Aston Martin V12 powered jet boat – those are all fundamentally more difficult of an endeavor than what I went with, and multiply the complexity significantly. So while you’re doing all of your research, make sure you know why you’re doing it – and what the specific goals you want to achieve are. That will make it much easier to filter through the myriad of opinions on things like cam duration or compression ratio, and find the one that best suits what you’re looking for.
I Love it When a Plan Comes Together!
So why did I chose a naturally aspirated Big Block Chevy with EFI? There’s a few reasons. First and foremost is that, in the performance marine world, the Big Block reigns supreme. Other than proprietary overhead cam builds in today’s top of the line Mercury Racing engines, the majority of fast boats use a Big Block Chevy. And as it turns out, they have a good reason for it – which are also reasons I shared.
- There are a *ton* of them.
Other than the Small Block Chevy, the “BBC” has been around for an incredibly long time, and has enjoyed an incredibly prolific career. It’s larger displacement has landed it in high end muscle cars, sports cars, boats, jet boats, mud runners, hill climbers…nearly everything you can think of. They have been produced, continuously, almost completely unchanged, since *1955* – and are still produced brand new, in crate form, today. That’s 65 years and counting. Sure, there’s the Mark IV vs Gen 6 changes and everything…but other than a small block chevy, “The Rat” is pretty much the most common engine there is. This means parts are cheap, plentiful, and available in any combination you could imagine. - Boats need torque, and Big Block’s have it.
There’s an old saying that there’s no replacement for displacement. While forced induction and other methods have been trying to make up for it, the adage still mostly rings true…especially when it comes to boat engines. Car engines spend most of their life relaxing, lazily rumbling along barely off idle at a few thousand RPMs, max. Squeezing more and more horsepower out of smaller and smaller, higher and higher RPM engines works great for cars…because they almost never need to do anything difficult. Boat engines are under max load, at high RPM, their entire life. They work hard, so they can’t use any tricks to make their power. The natural laws of physics demand that more torque means bigger displacement…and the Big Block has exactly that. My particular build is 492 cubic inches, or *8 liters* of displacement. That is literally 4 times bigger than my car engine, at 2 liters…even though it only makes about double the power. That’s what it takes to get a boat on plane, and to run at heavy load at high rpm for hours on end – and the big block has it in spades. - They’re freaking awesome.
Sure, LS swaps are all the rage…and all sorts of sub culture have their own revered engines like the 2JZ or the Boss 302 or the W16. But other than a hemi, there’s very few engines that look, sound, and feel as imposing as a BBC. It’s old school, in the best way possible, and while it might not be as efficient or advanced as more modern engines, it makes up for that with it’s abundance of character, power, and charm. Despite the fact that it came out in 1955, it is still one of the coolest, most powerful engines money can buy…and you don’t need much to buy one anymore!
So there you have it. After spending years looking over things, I’m starting to build the engine for Limitless – a 491 Big Block Chevy. As the series progresses we’ll go over what components I chose and why, what tools you might want and need, what prep work goes into everything, how the actual build goes, and – hopefully – a successful dyno run and installation into Limitless. Fingers crossed!
– Dennon
