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Engine Building Fundamentals: How To Use A Ring File

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How To Use A Ring File


00:00 - In this module, we're going to take a look at how to use a ring file to correctly file our piston ring end gaps.
00:07 Now in front of me here I've got two different ring files, we've got our cheap, manual ring file, which is going to be ideal if you don't want to spend a lot of money, and perhaps you're only going to be building one or two engines, and we've also got an electric ring file, which is also fitted with a dial indicator.
00:26 Now the dial gauge on the electric ring file makes it very easy for us to make very precise changes to our piston ring end gaps, and this allows us to get very repeatable and precise end gaps across the entire ring set.
00:42 The manual ring file is a little bit more fiddly and a little bit more tricky to use, it also tends to take a little bit longer to get the right result, because we're forced to use the trial and error method, where we will fit the ring into the block, measure the end gap, file it slightly, and then take it back out of the file and check it again, so this is a process that we're going to iteratively repeat until we get our end gaps where we want them.
01:10 Now before we actually look at using the ring files, we're going to check out how to go about measuring our ring end gap, and we're going to do that by taking our ring here, and we're going to fit it into the Toyota 2JZ cylinder block behind me, so let's start by doing that now.
01:31 So we're going to begin by placing the ring into the top of the bore, and here I'm just looking at number one cylinder.
01:39 So I've just done this by compressing the ring slightly by hand.
01:44 I'll also point out here that it's important when we're going to be filing our rings to make sure we assign our rings to a particular cylinder.
01:54 There's quite often going to be very minor differences in our bore diameters, and this can ultimately affect our ring end gaps, so we're going to file our ring set to suit a particular cylinder, once that's done, those rings are going to stay with that particular cylinder.
02:10 Now we've got our ring located in the top of the bore, but this isn't where we want to actually make our measurement, what we want to do is move the ring slightly down the bore before we take our measurement, and we also want to ensure that the piston ring is square in the bore before we take our measurement.
02:30 If we've got the piston ring slightly offset in the bore, this will make a big difference to the ring end gap.
02:38 Now there's a couple of ways we can achieve this.
02:41 I've got here a relatively cheap tool that can be used for squaring the piston ring and the bore.
02:48 This will suit a variety of different bore diameters, and all we need to do is rotate it and lock it down so it fits inside our specific bore diameter.
02:58 Once we've done that, we can just push down on top of the piston ring, and there's little sleeves here that stick out and protrude, and these will locate on the deck surface of the block, ensuring that the piston ring is located the correct distance down from the deck surface.
03:15 Once we've done this, we can use our feeler blades to check the ring end gap.
03:22 Now, if you don't have one of these tools, another really common way of achieving the same result, we'll just take our ring back out and locate it at the top of the bore again.
03:32 Another really common way of achieving this is to use a spare piston or a secondhand piston, and what we want to do is install one ring on the piston, and then we can install the piston into the bore upside down, and this is just going to move the ring down and we're going to move down until the ring installled on the piston hits the deck surface of the block.
03:57 This is going to achieve the same aim, we're just simply making sure that the ring is square in the bore and it's down slightly from the top of the bore.
04:08 Now, when we're measuring the piston ring end gap we're obviously interested in the width of the ring end gap, but another aspect that's really important to take note of is whether the ring end gap is square, we really want a parallel ring end gap.
04:24 If there is a taper and the ring end gap is offset, we're going to need to correct this when we're filing the ring end gap.
04:33 OK, so we've taken our measurements, now we know what clearances we need, or what additional filing we're going to be doing to achieve our target end gap, let's now look at how we can use the ring files to achieve this.
04:46 While the manual ring file is a relatively simple piece of equipment, there are also some traps and it's important to understand how to use it to get the best results.
04:56 One of the key points we need to remember is any time we're filing the ring, we always want to watch the rotation of the grinding wheel.
05:04 What we want to do is grind from the outside of the ring inwards.
05:09 Now what this is going to do is prevent any of the inlay being pulled out of the ring by the grinding wheel, and this is particularly important if you're using a ring that has a moly facing, so we always want to be grinding from the outside of the ring towards the inside.
05:25 Now typically, when you're using one of these ring files it will be located in a vice or bolted to a workbench so it can't move, for our demonstration though, we've just got it sitting here on the workbench.
05:37 Now, a lot of people when they use these ring files, they will locate the ring on the side of the positive stops or dowels, and then they'll squeeze the ring together so that both sides of the ring are being filed simultaneously.
05:53 Now, while that might sound like a sensible way of approaching grinding the rings, what that's actually going to do is ensure that your ring end gaps don't remain square or parallel, once the ring is installled in the bore.
06:07 And in fact, the only way you'll end up with parallel end gaps, is if your ring end gap works out to be the same thickness as the grinding wheel, and that'd be very, very unusual.
06:19 So in this case, what we're going to do is grind one side of the ring only, and what this does require is a little bit more attention, what we're going to have to do is manually view the end gap of the ring, and make sure that we're always holding the end of the ring square against the grinding wheel.
06:37 And the way we do this is we're going to constantly make small adjustments by grinding the ring, then take the ring off and check it in the bore.
06:46 This allows two things, first of all, we're going to be able to check our progress, so we're going to make sure that we don't end up with an end gap that's too wide, and it's also going to allow us to ensure that we are still maintaining a square ring gap.
07:02 So the process is to gently apply some pressure against the locating dowel, as well as locating the ring against the grinding wheel, and then we're just going to manually turn the grinding wheel until we've removed some material.
07:17 And it is an iterative process, we're going to be constantly rechecking our progress in the bore to make sure that we creep up slowly on our end gap, without going past it.
07:28 Our electric ring file offers many advantages over our manual ring file, not least of all is that it's much easier to locate the ring, to ensure that we are grinding the ring end gap squarely, and there's a couple of features on the ring file that allow us to do this.
07:47 First of all, we have an adjustable stop, which we can move so that we can always locate the ring or relocate the ring on the ring file in the same place, so we can adjust the stop, depending on the bore diameter that we're working with.
08:03 Then we also have of course the dial gauge, which allows us to make much more precise adjustments to our ring end gap.
08:12 So the process is to start by taking our ring, and we're going to locate this in our ring file.
08:18 Now I've already adjusted our stop or our locator, to make sure that my ring end gap is going to remain square, I'm going to install the ring with the ring protruding slightly from the platform here, or the deck, and then I'm just going to tighten the stop down to positively retain the ring.
08:39 Now what we're going to do is just slide the mechanism down, and I'm just going to adjust it until I'm just barely making contact with the grinding wheel.
08:50 Now at this point we can zero our dial gauge, and this is going to give us our zero point.
08:56 What we can do now is begin by moving the ring back down with our file now going, and we can simply turn the knob and remove material, slowly but surely.
09:08 What we want to do is remove a very minor amount of material with each pass on the grinding wheel, somewhere in the region of about 1/2 a thou per adjustment.
09:17 And what we can do is constantly recheck our progress using the dial gauge.
09:21 Even though we have the dial gauge, I still like to stop short of my final measurement, place the ring back in the bore, and have a final check and see how we're looking, compared to our target measurement, this just ensures that we don't overshoot our ring end gap, it's always best to measure twice and cut once.
09:42 Once we've completed filing our rings we've got one last task to complete.
09:47 The filing process is going to leave minor burrs on the edges of the ring, where the file has been removing material, and what we need to do is just remove those burrs, and this can be done with a light piece of sandpaper, or a very fine needle file, and what we want to do is just barely break the edge of the ring and remove those burrs.