Practical Engine Building: Step 1: Initial Preparation
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Step 1: Initial Preparation
07.25
| 00:00 | - In this worked example, we're going to be covering the build on a GM LS1 V8. |
| 00:06 | Now while we are using the LS1 block for this particular build, most of what we're going to be looking at in the procedures that we use during the build, will still be applicable to the rest of the GM LS range of engines. |
| 00:19 | Now in this case the LS1 is a 346 cubic inch or 5.7 litre V8 engine. |
| 00:25 | Now what we want to do is add a little bit of capacity to that engine and we're building it up with the intention of it being a fast street engine, we're looking for something that can comfortably make around about 550 horsepower with good mid range torque. |
| 00:41 | Now for this reason, what we're going to be doing is adding a K1 stroker kit to the engine. |
| 00:46 | Now with the LS1 block, one of the limitations here is the bore diameter. |
| 00:50 | The LS1 runs a very thin sleeve and this really limits what we can do in terms of the bore diameter. |
| 00:57 | We're not really able to bore the block itself and what we actually need to do is make sure that the bore is in good enough condition that we can just apply a light hone in order to suit our pistons. |
| 01:09 | So the finished bore diameter in this case is going to be 3.903 inches. |
| 01:14 | Coupled with the K1 stroker crankshaft, this is going to give us a stroke of four inches and it's going to take our capacity out to approximately 383 cubic inches, or about 6.3 litres if you prefer to work in metric terms. |
| 01:30 | Now that's going to give us a good bump in capacity. |
| 01:33 | As well as this we're also going to be fitting a slightly more aggressive camshaft, offering more lift and more duration on both the inlet and the exhaust. |
| 01:42 | In order to ensure a reliability from our new rotating assembly, we're going to be fitting a set of Wiseco forged pistons. |
| 01:51 | Now these are a 2618 forging so this is designed for high performance applications and in this case we are also raising the compression to 11.5:1. |
| 02:02 | This is probably about as far as we'd like to go with the compression on this engine, given that predominantly it is still going to be running on pump gasoline. |
| 02:12 | So when we're choosing our compression ratio, we do need to be a little bit mindful of that. |
| 02:17 | So with the components that we've chosen for this LS build, these are probably in line with what a lot of people would be selecting for a moderate LS V8 assembly. |
| 02:27 | In terms of the cylinder heads, in this case we are going to be retaining the stock heads and at this point they aren't going to be touched. |
| 02:34 | So this would be one area for further development if we did want to improve the power, the cathedral port heads on the LS1 engine are known to not be the best flowing heads available so obviously we have options there of complete aftermarket head assemblies or alternatively the heads that we have could be ported and larger valves fitted. |
| 02:56 | For our build though, we're going to be just leaving the heads as they are and we're going to really be concentrating on everything we're doing to the bottom end. |
| 03:04 | So our donor engine in this case for our build is a high kilometre LS1 engine that we've sourced from a local wrecking yard. |
| 03:12 | Now one of the concerns with this is that as I've mentioned, we can't bore the block. |
| 03:18 | So we really are relying here on finding a block where the bores are already in good enough condition that they will clean up with a light hone, allowing us to achieve the correct piston to bore clearance while also ensuring that the bores remain round. |
| 03:34 | So that's one of our biggest considerations there, obviously in this case we are going to be replacing the crankshaft, the conrods and the pistons so we're not really too concerned about the condition of those items. |
| 03:46 | As we'll see in the next step though, our engine has obviously not been well maintained and we've got a lot of carbon build up inside the crankcase. |
| 03:54 | So this is something that's going to need to be dealt with during the engine machining and engine cleaning process. |
| 04:02 | Now we'll have a look at the components that we've chosen for this build in a little bit more detail. |
| 04:08 | Starting with that K1 Technologies stroker crankshaft. |
| 04:12 | Now in this case the K1 Technologies crankshaft is a forged 4340 crankshaft. |
| 04:17 | In terms of the actual strength, this is probably overkill for our actual aims with the build however this was an essential aspect if we wanted to find a crankshaft to provide us the four inches or 100 mil stroke that we needed in order to achieve the increase in capacity. |
| 04:34 | So the crankshaft itself is complete overkill for our power aims and in terms of engine RPM range, we're probably likely to only spin this engine to approximately 6500 to 7000 so again this crankshaft is more than up to the task. |
| 04:49 | Now it is also worth mentioning here that the K1 Technologies crankshaft is a six counterweight crankshaft. |
| 04:57 | Some of the crankshafts available in the aftermarket are known as a full counterweighted or eight counterweight or alternatively centre counterweight style crankshaft. |
| 05:07 | Now these are potentially a little bit more suited to higher RPM and higher power applications however they also will not fit in the stock LS1 engine block without modifications or machining work to the engine block. |
| 05:21 | So that's important to consider if you are looking at a full counterweighted crankshaft. |
| 05:27 | As part of that rotating assembly, we've also got our Wiseco forged pistons which I've already mentioned. |
| 05:33 | Now it is really important when selecting components for a V8 engine such as our LS1 to consider the rotating assembly in its entirety. |
| 05:43 | Particularly with a stroker kit like this, what we need to consider is that the mass of the pistons and the connecting rods need to be factored in when balancing the crankshaft. |
| 05:53 | The mass of the connecting rods and the pistons are used to calculate a bob weight which is physically attached to the journals of the crankshaft during the balancing process. |
| 06:05 | Now we can get ourselves into a situation if the mass of the pistons and the connecting rods are not well matched to our crankshaft where we may have to have our engine machinist add heavy metal to the counterweights of the crankshaft. |
| 06:17 | And this is a time consuming and also very expensive process. |
| 06:21 | Another important point to note here is that if we do intend to perform any of the balancing work on the pistons and the connecting rods ourselves then with a V configuration engine, this is essential to perform before the components are supplied to our engine machinist, otherwise if we balance these components or adjust their weight once we get the crankshaft back from balancing, this will be detrimental to the overall balance of our engine. |
| 06:47 | In terms of the other hardware that we're going to be fitting to this engine, we're going to be using a set of ARP head studs and main studs to improve clamping on both our main bearings as well as our cylinder heads and we're also going to be using a set of King Performance racing bearings for both the main bearings and our big end bearings. |
| 07:07 | Lastly, the remaining components such as oil pump and water pump will be genuine GM factory components. |
| 07:14 | Now with our planning out of the way, let's move on with the next step of our process and start disassembling our base LS1. |
