This is part 4 of many in Limitless’ engine build. – be sure to check out the rest of the posts there. A nice, spotlessly clean block, with a crank installed and ready to go!
Ok, we’re finally going to start putting everything together. We’ve planned the build, done tons of research, selected all of our parts, found a great machine shop we trust, and everything is now ready to go!
Step one? Clean, clean, and clean some more…and at some point, drop in a crank (get it?)
Clean, Clean, and Clean some more
It cannot be stressed enough that everything – and I mean everything – needs to be spotlessly clean before assembly. In the previous article I discussed tolerances, and how for my engine we needed to up the tolerances from ~28 tenths to 32 tenths. That means 4 tenths of a thousandth of an inch are what separates this engine from running well, and potentially damaging itself. For us metric folk, that’s 0.01mm. That’s basically the width of a red blood cell. That’s what’s separating your engine from a joyous, high power, long life…and destruction on first fire up.
…That being said, I can’t help but take this all with a small grain of salt. Production engines are not built in a clean room environment. 75% of the people on YouTube are not paying that much attention as they build successful engine after successful engine. Some people say that paper products of any kind have no place in the same room as an engine, because they can create microscopic fibers that can tear up a build…and then proceed to work on their engine in regular clothes, which themselves are COVERED in dirt, grime, the works. As I write this I have taken every precaution I possibly can to ensure cleanliness – and more importantly so has Jenn. But I am not working in a clean-room environment either. I guess what I’m trying to say is you need to take every precaution to ensure that your engine is as clean as possible…but also be realistic about what you can achieve. Some areas are also far more critical than others, as we’ll learn.
Clean vs. Extremely Clean vs. Spotless…What Matters?
When you’re cleaning and building an engine, different areas need different attention to detail. In some cases, that “one red blood cell” of contamination really will do damage. Other areas, your engine won’t even notice. Let’s go over what matters, and what doesn’t – in that order.
Oil Galleys and Assembly Lube surfaces.
These are by far the most important area to get literally spotless. Any part of the oiling system after the filter, and any critically clearanced components, cannot afford to have anything in them. Any contaminant in this area will ruin your engine the very first time you start it up – because the filter won’t be able to stop it before it hits some critically clearanced area and does it’s damaged. Thankfully, this separates into two relatively easy to clean areas…the oil galleys, and the precision surfaces. The precision surfaces also need assembly lube, and ultimately it’s a good bet that if something needs assembly lube, it also needs to be spotlessly clean before assembly, and vice cersa…so your crank bearings, rod bearings, piston pin bore, lifter bores, valve stems, and cam bearings. Of course, the mating surfaces (crank mains journals, crank rod journals, piston pin, lifters, valves, and cam) should also be spotless.
The oil galley, in it’s entirety, also needs to be spotless. Your shop should have cleaned the block already, but you should still do it again…2-3 times, if not more. It’s pretty simple – use some presurized water, some good soap and water, and then some mineral spirits. A dedicated brush kit is also essential to ensure you can physically dislodge stuff in all the various passages. First you pull every single plug on your block…and everywhere there’s a plug, you clean. Start with the water, then use the soap and brushes, then more water, then mineral spirits, then compressed air to dry everything***. Then, repeat…over and over again until everything is spotless. There’s also a few other holes that will likely need cleaning, so make sure you get those too! On a big block, there are a few key areas:
- The two lifter galleys…with two plugs at the back and two at the front, so you can feed the whole way through. Don’t forget the lifter bores themselves!
- The main oil galley, which runs down one side of the block. Again, there is a plug at the front and back, so you can feed the whole way through.
- The main oil feeds. There are a ton of little plugs alongside the block that all need to be removed, so you can access the transverse feed lines from the main oil galley to the middle of the block, which then split to feed the cam and crank.
- The through holes that connect the cam and crank…easily spotted in the bottom (top?) of each mains on the block.
- The crank itself has oil passages for all of the rod bearings – don’t forget these!
- There’s also a ton of oiling stuff at the rear of the block, by the oil pump / filter / rear mains. Get all this stuff too.
Once all this stuff is thoroughly clean, it’s best to just unload some WD40 on it to keep it all rust free and ready for assembly lube (if it’s a machined surface) or for when it finally gets some oil (oil galleys). With that done, you should re install all of your oil plugs with some thread sealant. There’s no real torque spec…just get them tight enough that the taper has seated, and you’re good to go.
Less critical but still very important stuff
This is everywhere that will see oil, but after any critical surfaces and before the filter. In theory, any crap here will get caught by the filter before it’s pumped to anywhere super critical. This includes the whole lifter valley, everywhere closed off by the valve covers and timing chain cover, the oil pan itself, etc. You should still try your hardest to get this as clean as possible – but it’s not as critically important, since this area will get quickly washed (and then filtered) by the oil and oil filter once your engine starts up.
Surprisingly not very important stuff
This stuff should still be clean! It just doesn’t need to be over the top spotless. This basically covers anywhere there isn’t oil – so the air and coolant areas. In a marine engine, the coolant areas are literally going to get flushed with water and filled with gunk for the rest of their life anyways, so it’s almost not important at all. The airflow areas are critical just because they interact with the cylinder bore. To be extremely clear, even a small metal flake or piece of debris will cause damage here…but a bit of dust, a greasy finger print, etc isn’t as big a deal as it would be on your mains bearings (for example)
***A Very Critical Note on Water and Iron, and How They Don’t Mix.
Water and iron don’t mix. They form rust. Most people know this, but haven’t experienced just how dangerously quickly it happens first hand. You have seconds to get water off certain areas of an engine before it rusts and damages things. I didn’t mistype – seconds. Most critically are the cylinder bores. The very fine cross hatch pattern the machine shop left is rust’s best friend, and if you leave them for even a minute or two with drying water, they will begin to rust. In general, with the exception that cylinder bores (and valve springs!!!) are now priority number 1, the above list serves as an equally good list of where to not get things wet. When I cleaned my block, I had Jenn help me. Her only job was to keep the cylinder bores completely dry and covered in WD40 as I went around cleaning everything. Did she hate it? Probably. Did we go through an entire can of WD40? Yes. Did my cylinder bores stay dry and rust free? Yes – and in this case, that’s what matters.
Ok, we’re FINALLY Going to Start Building the Engine!
I know it’s been a long wait, but like most things in life, preparation is half the battle! Now we can finally drop in the crank. The crankshaft is one of the most important parts of the engine – it literally turns the force on the pistons into rotational power. Other than the block, it’s the heaviest and single most expensive part in an engine. In my case I went with a Scat brand, forged 4340 steel, 4.250 inch stroker crank. It’s part of the overall rotating assembly as they all work together to determine the displacement of your engine, and ensure everything works together. In other words, your rods need to fit both your crank and pistons to ensure everything fits just right.
Installing the crank is actually relatively easy if your machine shop has done all the work. First, you clean everything. Then you lube and install the crank / mains bearings in the block, being sure to align everything. Then, likely with some help from a friend, you very gently place the crank onto the mains bearings – being sure not to nick it anywhere. Don’t forget the rear main seal at the back of the block under the #5 mains! Then, put all of the bottom half of the crank / mains bearings in the mains caps, lube the bearing surfaces, and install the mains caps one by one – again not forgetting the second half of the rear main seal. The caps will need a light touch with a rubber mallet to seat, and then you can torque the bolts to a relatively loose figure (20 ft lb is what I used) until they’re all seated. At this point, you can triple check your crank axial end play (if you want), before torquing down the mains bolts or studs to the final torque. Be sure to use the right fastener lubricant and torque them in the right sequence, to the right spec!
And…that’s it. The crank is installed! It should spin almost effortless, which is impressive considering you just torqued no less than 20 bolts to 110 ft lb of torque to clamp it down. Critically, the your engine is now spotlessly clean, so it’s important to keep it completely covered from this point forward. There are dedicated engine storage bags…but I just used a contractors xxl size garbage bag to keep it clean. Otherwise, take some time to appreciate what you’ve just accomplished. After years of planning and anxiously waiting…the build is finally underway!
