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Engine Building Fundamentals: Crankshaft Installation

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Crankshaft Installation


00:00 - Once the engine block is prepared and cleaned, we can fit the crank shaft into the block.
00:05 The first step prior to fitting the crank shaft is to clean and install the engine bearings.
00:11 It's important to understand that some engines utilise different halves to the main bearings.
00:16 The bearing shell destined for the block side will include holes or slots that align with the oil galleries in the block, while the shell destined for the cradle or bearing cap side may have none.
00:29 Failure to use the correct bearing shell in the correct location will result in serious damage to your engine.
00:36 Once the bearing shells are installed, it's important to apply a thorough coat of lubricant to the bearing surface prior to installing the crank shaft.
00:45 There are specific assembly lubricants available for this task, and these are designed to offer added protection during the initial engine start up.
00:55 Alternatively, you can also use a quality mineral-based engine oil to do the same job.
01:01 In particular, some of the assembly lubricants tend to be quite a lot thicker in viscosity, when compared to a normal grade of engine oil and in colder climates this can make the engine feel tight when the main bearing caps are torqued down and you turn the crank shaft.
01:18 This can make it hard to be confident that the crank shaft is turning as freely in the block as it should.
01:25 There are many engine builders, who rely exclusively on assembly lubricants, while just as many will use plain engine oil, so the choice is yours depending on what product you're most comfortable with.
01:38 The crank shaft can now be gently lowered into the block and located in the bearing shells.
01:44 If your engine uses a separate thrust bearing, this is the time to install these too.
01:50 Thrust bearings generally have a flat side that faces the engine block, and the actual bearing surface, which will often have one or more oil grooves, which faces the crank shaft.
02:01 While some thrust bearings include a locating tag that require them to be installed prior to dropping the crank shaft into place, if the design allows for it, I prefer to slide them into place once the crank is installed, and this prevents any possibility of the thrust bearings becoming dislodged and damaged while the crank shaft is being lowered into place.
02:24 Now we can install the other half of our bearing shells into the main bearing caps or the cradle.
02:30 Again, we're going to lubricate these bearing surfaces before installing them into the block.
02:36 Initially, we're going to simply install the cap or cradle onto the crank shaft and then install the fasteners and torque down the caps.
02:45 It's important when tightening these fasteners that you follow the procedure laid out in the workshop manual.
02:51 Typically this will involve tightening the fasteners in stages, as well as moving in a specific order from the inside cap outwards to ensure that the caps are torqued down evenly.
03:04 Finally, we want to rotate the crank shaft and ensure that it rotates smoothly.
03:09 Contrary to popular belief, the crank shaft is not going to happily rotate ten times or more with just a light touch, but it also shouldn't offer any undue resistance to movement and should feel smooth throughout a full rotation.