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Practical Engine Building: Step 8: Cylinder Head Assembly

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Step 8: Cylinder Head Assembly

12.21

00:00 - The next step of our process is to assemble our two cylinder heads so that we can move on and assemble our complete long block.
00:07 Now we've got our cylinder head here in front of us, or one of our cylinder heads at least, and of course one of the steps before we start assembling our head castings is to make sure that they are thoroughly cleaned down and again you can refer to the cleaning step of the process if you want some more information on what's involved there.
00:25 Particularly with the fact that we do have a push rod engine here with our LS1, the heads are relatively basic, meaning that our cleaning process is pretty straightforward.
00:35 Now with these heads, they were in pretty poor condition visually when we disassembled our engine, there was a lot of caked on dirt and oil through the heads and one of the processes that we've had our engine machinist do is to thoroughly clean the heads.
00:51 The heads have also been externally vapour blasted which is a great way of removing all of that built up grime, bringing the natural surface finish back of the aluminium, essentially giving us a casting that looks pretty much like new.
01:03 While our machinist had the cylinder heads, we also got them to go through and check the valve to guide clearance, making sure that there wasn't any excessive wear in any of those guides and also recut the valve seats giving us our nice fresh valve seat so that we know that our valves are going to seal perfectly when they're closed.
01:21 Now the components that we're going to be fitting to the cylinder heads, we've obviously got our stock valves as explained there.
01:27 We have got a fresh set of valve guide seals.
01:30 Now it's important to note here that the valve guide seals for the LS engines, there are two styles, the style that we're using is a one piece seal which also incorporates the spring platform.
01:43 The other option is a two piece system where there is a separate spring platform or spring seat and then the guide seal drops in over the top of the guide.
01:51 Now the other thing with these valve guide seals is it's important to mention that there is a guide seal for the intake and the exhaust, we need to make sure that those are around the correct way.
02:03 On top of this we will be fitting a set of aftermarket beehive style valve springs from Kelford Cams, these are designed to suit the Kelford cam that we are running.
02:13 And any time you are running a more aggressive cam with more lift and more duration than stock, you do need to be mindful of making sure that the valve spring that you are using is suited to that particular cam.
02:25 So this comes as a matched package from Kelford so there's no problems there.
02:30 We're using an aftermarket set of COMP retainers and then we're using the factory collets or locks to lock everything in place.
02:39 So what we're going to do is start by installing our valve guide seals.
02:43 These are relatively simple to install, what we're going to do is take the valve guide seal and we've got a tube socket that's just a neat fit over the entire valve guide seal, it sits on the spring seat and then using a plastic hammer we can tap these into place.
02:59 Before we do this, we are going to lubricate the inside of the valve guide seal with some clean engine oil, so let's go ahead and do that now.
03:17 Again it is important here to take note of the correct order.
03:22 In this case the valve guide seal that I've picked up initially is actually an intake valve guide seal so we're going to start by installing that.
03:30 And that'll just drop down into place there.
03:33 Once we've got it located approximately, we can get our socket into place here, and just a gentle tap with our plastic hammer will get that into position.
03:44 We're going to now repeat that process for our remaining valve guide seals.
04:08 We've now got all of the valve guide seals installed so what we're going to do is take the cylinder head and we're just going to flip that upside down so that we can begin installing our valves.
04:18 Now before we install the valves, it's always a good idea to go through and just lightly lubricate the valve guides themselves, so we're just going to squirt a small amount of our clean engine oil down each of the guides.
04:34 The other thing I'm going to do here is just use a small amount of our oil just to lubricate the valve seat itself.
04:47 Now that we've got our valve guides and our valve seats lubricated, we can go ahead and install our valves.
04:53 You obviously want to be sure here that you are installing the valves in the correct location and in this case when the heads were disassembled, our engine machinist has actually made a small mark on the under head of each of the valves so that we know what location each valve goes in.
05:08 So again what I'm going to do is just apply a small amount of lubricant to the valve surface while I'm installing these, so let's go through that process now.
05:26 With all of our valves now installed in the cylinder head, we're going to flip the cylinder head back over and locate it in a way so that we can easily work on the valves and install our valve springs using our valve spring compressor.
05:38 The next step I'm going to take here as a precaution is I am going to wear a pair of nitrile rubber gloves.
05:46 So this is something that's advisable with some of the materials that the valve springs are made from.
05:52 The oils from our hands can end up being corrosive and can potentially cause damage to the valve spring material, resulting in failure down the track.
06:01 So it is a good idea if you're working with aftermarket valve springs to make sure you are wearing nitrile gloves.
06:08 What we're going to do now is we're going to take one of our valve springs here and we're just going to locate it over our valve, just making sure that it's sitting down on our valve spring seat and we're going to then take one of our retainers.
06:23 I'm going to just apply a small amount of our assembly lube on the underside of the retainer and this is just going to help when I install that retainer onto the valve spring, this is going to help make sure that it's not going to fall off while we're getting our valve spring compressor located.
06:41 So we'll just make sure everything's sitting OK there and we're going to take our valve spring compressor and we're going to get that located first of all on the head of the valve on the underside and then we're going to make sure that our valve spring compressor is rotated so we can easily access our collets.
06:57 Get it located properly onto our retainer and then we can just apply pressure here and compress the valve spring itself.
07:21 Now I find when we're dealing with some of these heavier or stiffer springs that we find in a overhead valve engine like the LS, it's a good idea to start with our valve spring compressor set up so that it's not actually going to compress the valve spring all the way down, so we've got access to the collet groove in the valve.
07:41 If we do that, we're going to require a huge amount of effort in order to compress the spring, it makes our job really difficult and it also means that we've got a little bit less control over the valve spring compressor while we are working on it.
07:53 So instead I've set up the valve spring compressor so that I can relatively easily compress the spring and then once I've got it to a point where it's compressed and locked, I'm just going to support the valve spring compressor and we're going to wind the end of the valve spring compressor in to a point where we've got access to the collet groove in the valve.
08:13 So let's go ahead and do that now.
08:18 Alright we've got our valve spring now compressed to a point where we've got good access to the groove in the valve.
08:23 And you can see I've got the valve spring compressor in a situation where it's relatively well balanced so it's going to sit there by itself.
08:29 Meaning that it frees up both of our hands to work on installing our locks or collets.
08:34 And that is the next step here, we're going to take one of our collets and what we're going to do just to help the process here, this can be quite fiddly, is I'm just going to apply a little bit of our assembly lube to the collet and this will just help support that collet as we get it into location here.
08:53 Now this can be a little bit fiddly, it's going to take a little bit of time to manipulate the collets into place and you'll find at least for the first couple of valves this can be really really frustrating and quite fiddly.
09:04 What you'll find though is your formulate a bit of a process that you go through here and once you've got that process down, after the first one or two valves you'll find it's going to go a lot easier.
09:14 So let's go ahead and get our other collet into place.
09:40 Alright so at this point we've got both of those collets correctly located in the groove in the valve.
09:46 Now it can be necessary just to manipulate the angle of the valve spring compressor while you're doing this just to make sure that you do have enough room to get that collet in and it's not going to end up contacting the retainer.
09:57 At this point we've got the next task which is to unwind our valve spring compressor so that the retainer evenly pulls up on both of those collets.
10:05 And this again can be a little bit fiddly, can take a little bit of time to get this right.
10:11 What we want to do while we are unwinding the valve spring compressor is to watch those collets and make sure that they don't start to come out or come off the valve as we're unwinding it, so let's go through that now.
10:30 Alright at this point I have taken most of the pressure off the valve spring compressor and by using the screw thread to unwind the valve spring compressor as I've been doing here, just allows a lot more control over the valve spring compressor, just to make sure that those collets do stay in the correct location.
10:46 At this point I'm comfortable they are both correctly located so now I'm going to remove the valve spring compressor completely.
11:00 And with our valve spring compressor removed it's a good opportunity to take one last look, make sure that you are completely confident that both of those collets are correctly located in the retainer and in the groove in the valve and with that first valve out of the way we can move on and we'll complete the remaining valves.
11:53 Alright at this point we've got the first of our cylinder heads completely assembled, we've got all of our valve springs, our retainers and our locks in place and we're confident that all of those locks are correctly located in both the retainer as well as the groove in the valve.
12:07 From here of course it's a rinse and repeat of this process on our second cylinder head.