Practical Engine Building: Step 1: Initial Preparation
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Step 1: Initial Preparation
09.07
| 00:00 | In this worked example we're going to be covering the build of a Honda K20 naturally aspirated engine that's going to be powering our Honda CRX endurance racecar. |
| 00:09 | The Honda K20 engine is in my opinion one of the best four cylinder naturally aspirated engines to come out of Japan, or for that matter just about any part of the world. |
| 00:20 | The amount of power it produces in stock form is exceptional and with some basic modifications this can be dramatically improved. |
| 00:29 | It's proven itself to be incredibly capable in both naturally aspirated and forced induction formats, be that supercharging or turbocharging. |
| 00:37 | This particular worked example as I mentioned will cover a 2 litre build of the K20 in naturally aspirated format. |
| 00:45 | However, essentially everything we're going to cover here can be applied to forced induction builds as well, obviously there's a few subtle differences, namely around the compression ratio. |
| 00:56 | It's also worth mentioning that there are a variety of different variants in the K series engine range and it's important to understand what you're getting yourself in for. |
| 01:05 | Probably the two most popular models to build up would be from the EP3 and DC5 Type R, Integra and Civic respectively. |
| 01:16 | These engines however, particularly in recent years, have become very very expensive as a place to build from, the specific engine that we will be building here is from a CL7 Euro R Accord. |
| 01:30 | For all intents and purposes, this really is essentially identical to the EP3 and DC5 variants. |
| 01:39 | There are some subtle differences, particularly with the cylinder head around the coolant flow through the head or coolant ports specifically in the head, also some differences with the oil pump, but again really this worked example will cover you irrespective ofwhich particular model you're building. |
| 01:55 | So, the aim with this particular build, as I mentioned, is naturally aspirated, we are limited in our class to a 2.0 litre, which is why we won't be using the 2.4 bottom end which is also a popular way of adding some capacity into the engine. |
| 02:09 | If you do want to build a 2.4 variant of the K series, again this worked example will still be 100% applicable to you. |
| 02:17 | What we want to do here is add a little bit more compression ratio into the engine. |
| 02:21 | Really when we're considering compression ratio, we do need to take into account the fuel that we're operating on. |
| 02:27 | We for endurance racing do not want to go to an alcohol based fuel such as E85, which would allow a higher compression ratio because the fuel burn is going to be excessive for an endurance race event. |
| 02:40 | It'd be fine if we were competing in sprint races though. |
| 02:44 | So, for this reason we are limiting ourselves to compression ratio of around about 12.5 to 1. |
| 02:50 | That should work nicely on the 100 plus octane pump fuel that we've got access to. |
| 02:55 | Let's go over the components that we will be using for this build and we'll start with the cylinder head. |
| 03:02 | This cylinder head really is the basis of the engine in terms of its power production and we'll be starting by sending the raw head casting out for a CNC port job. |
| 03:11 | We are matching the CNC ported head with a set of 1mm oversize Ferrea valves. |
| 03:17 | These will be then matched with a pack beehive valve spring and a titanium retainer from Kelford cams. |
| 03:25 | In terms of the cams, we are running a Brian Crower stage two cam, again this is a cam that we've had personal experience with and seen really good results with it. |
| 03:36 | These cams do retain VTEC instead of the more aggressive VTEC killer or VTEC delete style cam. |
| 03:44 | And we've found that this style of cam gives a really broad power band, which is exactly what we want. |
| 03:51 | We're building something that was maybe targeting drag racing use where our power band would be restricted to high RPM, I would be inclined to use a more aggressive cam with a VTEC delete style. |
| 04:02 | We are also retaining the continuously variable cam control on the intake cam and we will be matching this with a Vernier adjustable cam gear on the exhaust cam so that we can degree that to Brian Crower's specifications. |
| 04:16 | So, that covers the head itself. |
| 04:18 | Bolting the head to the block we will be using a fairly standardised off the shelf ARP head stud kit and we'll be using a Cometic 30 thou thick multi layer steel head gasket. |
| 04:31 | Even though this is a naturally aspirated engine, head gasket sealing is not quite as critical as it would be with a turbo application. |
| 04:39 | With the bottom end, we don't need to do anything too crazy here to get the sort of results we're looking for. |
| 04:46 | We're running a Wiseco forged piston, this is an 86.5 mm bore, so it is half a mil oversized, 20 thou oversized and that'll allow our machinist to bore and hone the block, getting our piston to cylinder wall clearance where it needs to be and ensuring that any wear in the existing block can be cleaned up. |
| 05:07 | We'll be matching these Wiseco pistons to a set of Brian Crower H beam rods, which should again be more than adequate for our purposes. |
| 05:16 | We're going to be aiming with this engine for around about 200 kilowatts at the front wheels and we'll be revving it through to about 9000 to 9500 RPM depending on the specific application that we'll be using it for. |
| 05:29 | As for the crankshaft, we'll be retaining the stock Honda crankshaft, it's again a well proven factory forged item, no problems with that, we will be having that crack tested and inspected by our engine machinist and unless we find anything going on when we strip the engine down, it should simply need a polish and it'll be ready to go. |
| 05:48 | With the bottom end we will also be incorporating a set of King Racing bearings. |
| 05:54 | Alternatively, you absolutely could use Honda bearings and during the assembly process I will also go through the process of how you specify the correct grade of bearing if you are going to be using the Honda bearings. |
| 06:07 | One of the more significant changes we will be making in this build is to do away with the factory oil pump and sump and instead we'll be running a Dailey Engineering dry sump system. |
| 06:17 | This incorporates a four stage pump and a billet sump. |
| 06:21 | The reason that we're doing this is two fold. |
| 06:24 | First of all, this is a circuit or road race application where we're expecting to see high lateral and longitudinal g forces. |
| 06:33 | So, oil surge with a stock sump can be problematic, yes there are solutions, which I'll talk about in a moment, but the dry sump system is a bullet proof way of solving that. |
| 06:44 | The other reason that we're doing this is that fitting the K20 into the Honda EF CRX chassis is tricky. |
| 06:52 | The K20 is a very tall engine and with a stock sump this really compromises where we can locate the engine in the chassis. |
| 07:00 | So, by going to the Dailey Engineering dry sump system, this is much much shorter than the stock sump, allowing us to fit the engine lower in the chassis and giving us more flexibility with where the engine will sit. |
| 07:12 | Now, I know that a dry sump system like this is obviously a big ticket item and it's not going to be suitable for every build. |
| 07:19 | Don't worry though, if you're retaining the stock sump and the stock oil pump, we will still be covering that process during this worked example. |
| 07:27 | If you are going to be using a K20 with a stock sump in a circuit race application, there are a number of off the shelf baffle kits that you can purchase, which have been well proven in race applications to reduce or eliminate surge. |
| 07:41 | Incorporating the daily engineering dry sump system also requires that we move from the stock harmonic damper to an ATI damper. |
| 07:50 | The ATI damper has a drive system, which allows us to then bolt the drive pulley on for that dry sump system. |
| 07:58 | The other modification that we're making, which is on the bench in front of me here is that we are going to be removing the factory inlet manifold and in its place we'll be running a set of Jenvey individual throttle bodies. |
| 08:11 | These can improve performance and they also allow us to tune the intake length by changing the length of the inlet trumpets. |
| 08:20 | This allows us to take advantage of the tuning effect of that trumpet length. |
| 08:25 | It allows us to adjust, essentially or optimise where in the rev range we achieve peak power. |
| 08:31 | This does result in some complexities when it comes to the tuning process which is obviously outside the scope of our engine building worked example, but if you do want some more information on tuning using individual throttle bodies, you can check our practical standalone tuning course. |
| 08:47 | There's a lot of information in there, tuning using the alpha N principle, using throttle position instead of manifold pressure. |
| 08:55 | Now, that we understand what we're doing, the parts we're using, we've got our initial planning out of the way, we can move on with the next step of our process. |
