Practical Engine Building: Step 3: Engine Machining
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Step 3: Engine Machining
26.59
| 00:00 | In the third step of our process we're going to be sending our engine hard components out for machining. |
| 00:05 | But before we do this, there are still some checks that we can go through here to make sure that all of the parts that we're dealing with are essentially within the clearance tolerances that we're after. |
| 00:16 | Specifically here what we will be looking at is our crankshaft, we've got on the bench in front of us, we'll be looking at our journal diameters and comparing those to our factory workshop manual. |
| 00:27 | We can also check our bearing clearances both in our big ends or connecting rod bearings as well as our mains. |
| 00:33 | The other big element with our engine machining of course is boring and honing the block to suit our new Wiseco pistons. |
| 00:41 | Because these are a 20 thou or half mil oversize, we're obviously not going to be able to really do any checks in terms of whether our bores are round, whether there's any tape or rebelling in them and checking our piston to cylinder clearance, that particular work will have to wait until we get our engine back from the machine shop. |
| 00:59 | So, let's cover off what we're going to deal with in this step here and now. |
| 01:04 | The first element we'll look at here is how to measure our crankshaft and check our journal diameters. |
| 01:11 | In order to do this we will need a micrometer and an understanding of course of how to use the micrometer, which we do cover in the body of the course. |
| 01:19 | We will also need to source a workshop manual so that we've actually got the factory specifications that we can compare this to. |
| 01:27 | Fortunately, with the K20 engine that we're dealing with now being reasonably old, coming out in the early 2000s, and the popularity, getting hold of the genuine factory workshop manual really is just a matter of a few moments on Google and you'll have a selection to choose from. |
| 01:43 | This is an essential element with the build though and we will absolutely be needing it as we progress through the assembly steps as well. |
| 01:50 | So, let's start with our big end journal. |
| 01:54 | So, we'll start with our number one big end journal here. |
| 01:57 | And in order to check that, what we're going to do is use our one to two inch micrometer. |
| 02:03 | I will be using imperial for our micrometer just to mix things up a little bit. |
| 02:08 | When we are using our dial bore gauge, which we'll get to in a moment, this is actually metric. |
| 02:13 | The reality here though is it just doesn't matter whether you are dealing in imperial or metric units and remember we can always switch between units if we just remember that there are 25.4 mm in one inch. |
| 02:26 | So, what we're going to do here is take our micrometer and we'll just drop this over our number one big end journal and we'll get it nice and central. |
| 02:35 | What I'm doing is just using the little thimble at the end of the micrometer and while I'm doing that I'm just wiggling it backwards and forwards, making sure that I have in fact got it locked up on the widest part of the journal. |
| 02:48 | Now, I have for simplicity here just taken one single reading. |
| 02:53 | The reality is that when we are measuring all of these journals on the crankshaft, what we actually want to do is take multiple readings. |
| 02:59 | What we want to do is take a reading on each side of the journal and this will allow us to measure any taper on the journal. |
| 03:07 | The other element is making sure that we take readings perpendicular to each other. |
| 03:11 | So, we're basically taking two points of reference and that will allow us to check that the journal is in fact properly round. |
| 03:20 | There are specifications in the workshop manual in terms of what the allowable out of round is as well as what the allowable taper is. |
| 03:28 | The reality here is that the factory K20 crankshaft is a high quality forging, so it would really need to have been beat up on pretty hard in its previous life in order to register out of round or a significant amount of taper. |
| 03:42 | However, it's always a good idea to measure rather than make assumptions. |
| 03:47 | Looking at our micrometer for our number one journal, we've got the measurement here for that journal and it is 1.8892 inches. |
| 03:56 | We can now compare that to our factory workshop manual and the minimum size is 1.8888 inches, the maximum is 1.8898 inches. |
| 04:07 | So, we're nicely within that range so that's a good place to start. |
| 04:11 | Now, the factory workshop manual does specify how to select the factory graded bearing shells if we are using those. |
| 04:21 | And for the next step when we're looking at our main bearings, I will go over that process if you are using graded factory bearing shells because it isn't something that we have dealt with much throughout the course of our practical engine building course up to this point. |
| 04:35 | So, we'll cover that for those who want to use the factory bearings. |
| 04:38 | In our instance though we are of course using the King Racing bearings, we've already covered that off and what we want to do is check our clearance. |
| 04:46 | So, in order to do that, what I've done is already gone ahead and assembled up one of our Brian Crower H beam connecting rods with the bearing shells already fitted. |
| 04:56 | So, I've basically gone through and assembled this just as if I was doing a final assembly of the engine. |
| 05:02 | Put that down for a moment. |
| 05:04 | Now, we've got our micrometer still locked up on our journal diameter for number one and what we want to do is take our in size dial bore gauge and we want to zero this on our micrometer. |
| 05:17 | So, the process again is covered within the body of the course if you need a refresher, but essentially what we're going to do is just locate the dial bore gauge between the two anvils of our micrometer and we just want to rock that backwards and forwards, getting the tightest point there, making sure that our needle is accurately swinging through the zero point, which we can see it absolutely is. |
| 05:40 | Now, we'll gently remove that from our micrometer. |
| 05:43 | So, we've now got our dial bore gauge essentially zeroed on the outside diameter of our crankshaft journal. |
| 05:51 | Now, if we use this in the big end journal of our conrod with our bearing shells fitted, this will show us the clearance. |
| 05:59 | Now, the important point to note here, just to reiterate, this is a metric dial bore gauge and I will admit that generally regardless whether we are working in metric or imperial units, all of our measurement tools would be in the same unit. |
| 06:13 | So, this is a little added complexity, it's not a big deal, but it is something we need to take into account so that we know we're not trying to read this in thousandths of an inch, because obviously we're going to end up with some very inaccurate results. |
| 06:26 | So, what I'm going to do now is just take the dial bore gauge, we're going to locate it in the journal and I'm going to be perpendicular to the parting face of the body of the rod and the cap. |
| 06:37 | So, let's get that in there now. |
| 06:39 | And we're coming through about four hundredths of a millimetre. |
| 06:43 | Or .04 of a millimetre. |
| 06:46 | So, we'll remove that now and again we can compare that to our factory specification or what we're trying to achieve. |
| 06:54 | So, let's have a look at our factory workshop manual now. |
| 06:56 | What we can see is that the recommendation here is a minimum of .033 of an inch and a maximum of .061 so we are nicely within that range at .04 or four hundredths of a millimetre. |
| 07:11 | Now, just to convert that into imperial, if we're working in imperial units, that works out to be right on 1.6 thousandths of an inch. |
| 07:20 | So, that is about as tight as I'd like to see these rod bearings, I'd probably be somewhere in the region of about 1.5 to 2 thousandth for our modified engine. |
| 07:29 | Bearing in mind here we are naturally aspirated so cylinder pressure isn't going to obviously be as high as if we're building a high output drag engine, that is one consideration. |
| 07:40 | And our rev limit here isn't really going to be super high, so we are going to be able to run pretty much within that factory range. |
| 07:47 | So, at the moment we know that our connecting rod bearing clearance is within the range or tolerance that we'd want. |
| 07:54 | Of course, we could have our machinist polish a little bit of additional clearance into that big end journal if we want, which is really one of the purposes of checking these things now. |
| 08:03 | So, if we find our clearances aren't exactly where we expect them to be, that gives us the flexibility of fixing that during the machining process. |
| 08:11 | Now, of course I've only dealt with one big end journal here, we would of course repeat that process for the remaining three, but the process is exactly as you've just seen. |
| 08:22 | So, this is the process we go through when we are using a micrometer and a dial ball gauge. |
| 08:27 | What I'm going to do for our next step of this part of the process is we'll have a look at our main bearing clearances , but this time we'll use PlastiGauge. |
| 08:37 | Again PlastiGauge and the use of PlastiGauge is covered in the body of the course, but we'll just go through that process here just to really help with those who are going to be using PlastiGauge, it is obviously a much more affordable product for the average home enthusiast than purchasing a dial ball gauge and a set of micrometers. |
| 08:55 | Before we look at our graded bearing shells though, let's just go over the process of measuring our main bearing journals and due to the size of this journal, we need to step up to a larger micrometer, this one will need to measure between two and three inches. |
| 09:08 | Again take our micrometer and we're going to again just lock that up on our number one journal, making sure that we do have that nicely located in the centre and we can lock that down. |
| 09:22 | Again the same information goes here, we would want to take measurements at each side of the journal and in two locations perpendicular to each other so we can measure our taper if any and our runout. |
| 09:32 | So, in this case we can measure that journal diameter at 2.1652 inches. |
| 09:39 | So, again we jump into our workshop manual and we can see that our clearance here should be between 2.1648 and 2.1657. |
| 09:51 | So, we are again nicely within that range. |
| 09:54 | So, depending where we are within this range also affects the grading of that particular journal and this is how our graded bearing shells work. |
| 10:04 | What we will find is that on the nose of the crankshaft we have some numbers etched into the crankshaft and those will reference the size of the journals. |
| 10:14 | We've got our big end as well as our mains marked. |
| 10:17 | And in this case the big ends are letters and the main journals are numbers. |
| 10:23 | Pretty easy to tell though because obviously we have five main bearing journals, we've only got four big end journals. |
| 10:30 | And the workshop manual also tells you, which location on the numbering or letters here on the crankshaft relates to which of those journals. |
| 10:38 | So, that's the first part there, that gives us the grading of those journal diameters. |
| 10:43 | Likewise, we have exactly the same reference on the factory connecting rods, irrelevant in our situation since we have swapped to an aftermarket rod, but of course on the block we also have the reference etched into the cradle for the block as well. |
| 11:00 | So, again the workshop manual tells you where to find that and it will also tell you , which number or reference relates to which journal. |
| 11:09 | Now, if we jump into our workshop manual, we'll be able to make sense of this. |
| 11:14 | Looking specifically for our example here at our reference for our number one journal on our crankshaft and of course the matching number one journal in our block, both are actually referenced as a number three. |
| 11:28 | So, if we look at the grid here in our workshop manual and we come down to our main journal code , which is three of course and we come across to our crank bore code, which is on the block, come across to three, or depending on your block we can see that it could also be C or three dashes for the number three. |
| 11:47 | Irrespective, this should be a green slash brown coded bearing shell or coloured bearing shell, that is what we would order from Honda. |
| 11:57 | Now, there is a little bit of flexibility here and there's also some considerations that we need to make if we are using the graded bearing system. |
| 12:05 | Now, obviously these codes that are stamped into the block in the crankshaft are done when the parts are all brand new. |
| 12:13 | Now, obviously we could expect some level of wear over time, more likely on the crankshaft journal so whether the crankshaft journal still measures up as a grade three bearing journal is up for debate. |
| 12:26 | So, this is one of those situations where we would want to confirm, never make assumptions, trust, but verify, so even if we are using graded bearing shells, it is really important to still actually check your clearance, whether you are going to be using PlastiGauge to do that or our dial bore gauge. |
| 12:41 | The other element here is that this graded bearing shell system should get you essentially in the ballpark in the centre of Honda's recommendation. |
| 12:49 | Now, that may not necessarily be exactly where we want to set the clearance for a modified engine. |
| 12:56 | As we know, the tendency is usually with high powered engines that are going to be making both more power and running to a higher RPM than stock, is that we tend to build the engine on the looser end of the factory scale. |
| 13:08 | However, we can swap those bearing shells, those graded bearing shells in order to achieve more or less clearance. |
| 13:13 | So, it gives us quite a degree of flexibility in terms of being able to essentially blueprint our bearing clearances. |
| 13:20 | You can also mix and match different coloured or graded bearing shells, top and bottom in the same journal and as per the factory manual, if you are doing that, it simply doesn't matter which side you're putting which bearing shell, it's still going to get you the same net bearing clearance , which is what we're after. |
| 13:37 | Alright, so at this stage we've demonstrated how we can measure our bearing journal diameters, both our big end and our main journals and we've confirmed there with number one journal diameters in both the big end and the mains that they are within our factory specification and again to reiterate, of course we would check all of those clearances, all of those journal diameters as we go. |
| 13:57 | Let's now rearrange the studio a little bit, we'll bring our block back in and we'll go through the process of using our plastic gauge in order to check our main bearing clearances. |
| 14:06 | Alright, so we've got our engine block back in our studio here and I've gone ahead and done some preparation before we can actually use plastic gauge to check our bearing clearances. |
| 14:16 | This starts with a basic clean down of the journal surfaces in the block and it's really easy to overlook this step, obviously we're not doing the final assembly so we're not overly worried about cleanliness, but what we're very likely to find is that when we remove the factory bearings or the existing bearings from the journals in the block and also in the cradle, we're likely to end up with lines of carbon deposits on either side of that bearing shell. |
| 14:42 | So, if we fit new shells, if those sit on top of those carbon deposits, it's going to impact on the measured clearance so we want to make sure that we use something like a green scotch bright and some brake clean just to remove any of those marks. |
| 14:55 | We also need to remove carefully the silicon that is used to seal around the outside of the perimeter of the block to that cradle, again just to make sure that that's not going to influence the results that we measure. |
| 15:08 | So, at this stage I've got our clean bearing shells fitted into the block. |
| 15:12 | It is important when we are using plastic agent in order to get good results to make sure that we don't apply any lubricant to either the bearing surfaces or to the crankshaft journals. |
| 15:22 | Likewise, we also need to make sure that our crankshaft journals have been properly cleaned down to make sure there's no existing lubricant or dirt or anything like that sitting on those that could end up affecting the measured clearance or potentially damaging our fresh bearing shells. |
| 15:39 | Obviously, because we've got no lubricant being applied here, it's really really important to make sure that during this whole process the crankshaft is not rotated, that'll absolutely definitely mark up our bearing shells and potentially the journals on the crank itself. |
| 15:53 | So, at this stage everything's nice and clean in the block so what I'm going to do is drop the crankshaft gently into place, again being sure that we don't rotate that while it is fitted to the bearing shells. |
| 16:09 | Ok, the crankshaft's in place and another tip when you're doing this as well is to make sure that you locate the crankshaft so that the oiling holes through those main journals are not located directly at the top, I've got these located at the side. |
| 16:22 | This is simply because this way is not going to impact where we can place our plastic age. |
| 16:28 | Now, what we want to do is cut or break off a strip of plastic age and lay this over the width of each of those journals. |
| 16:36 | So, let's go ahead and get that done now. |
| 16:43 | Right we've got our five strips of plastic age into location and just a little tip here as well, we do want to make sure that the length of the plastic age matches pretty closely to the width of the journal. |
| 16:54 | One of the nice features with using plastic age compared to a dial bore gauge and a micrometer is it makes it very easy, easier in my opinion to spot any taper on the journal, but in order to achieve that we do really want to make sure that our plastic age is at or very close to the full width of the journal. |
| 17:13 | Alright, so now what we want to do is get our cradle into location and we'll torque that down to Honda's specification, that specification being 22 foot pound of torque plus 56 degrees. |
| 17:26 | And if you are thinking that 56 degrees is an unusual torque angle, this is simply one hex movement on the head of the bolt. |
| 17:36 | So, relatively straightforward. |
| 17:38 | Now, before we drop our cradle into location, same information goes, we want to make sure that the journals are cleaned up using scotch brite, we want to make sure that all of that silicon is removed. |
| 17:50 | Gone ahead and already done that and we've got our bearing shells in location. |
| 17:53 | Another point before we drop that cradle into location is that we do want to just give the bearing shells a light spray with something like this silicon mist. |
| 18:03 | Now, this is in essence something of a lubricant, but it doesn't build up a film with any real thickness, so it will not affect the measurements that we end up making on our plasticage. |
| 18:14 | What it's there to do is stop that plasticage sticking to the bearing shells on our cradle, so the plasticage should now stay put on our crankshaft journals and that's going to make it much easier for us to take that reading. |
| 18:26 | So, what we'll do now is we'll get our cradle into location, we'll torque that down. |
| 18:31 | Once it's torqued down, it's simply then a case of removing it, prying it out of the way so we can see our plasticage. |
| 18:37 | So, if we do that now, we'll speed this process up a little bit. |
| 19:06 | Ok, so we've gone through that process, torqued everything down, we've removed that cradle, we've got our plasticage nicely still located on our journals and the very first thing we want to do here is take note of the width of the plasticage across the journal. |
| 19:21 | And what we're looking for here is consistency in that width. |
| 19:24 | Any inconsistency, so fatter at one end than the other is going to indicate we've got taper, so straight away we can see that everything's looking nice and consistent there. |
| 19:34 | So, no taper present so we can tick that off. |
| 19:36 | Now, we want to use a section of the plasticage pack and we're going to lay this beside our plasticage strip, get a sense of what the actual thickness is of the plasticage, width of the plasticage, which of course corresponds to our bearing clearance. |
| 19:52 | What we want to do here is also keep in mind what the factory specification is. |
| 19:56 | Of course, this comes from our factory workshop manual. |
| 19:59 | And interestingly here on journals one, two, four and five, the specification is between 0.7 of one thousandth of an inch and 1.6 thousandths of an inch with a service limit of 2 thou. |
| 20:13 | Conversely on the centre main, this clearance is a little bit looser between a minimum of 1 thou, maximum of 1.9 thou and the service limit of 2.2 thou. |
| 20:24 | So, again I'd be aiming towards the looser end of that clearance range around that 2 thou mark. |
| 20:30 | So, let's just compare with our plasticage pack and see what we've got. |
| 20:34 | And we see if we put our 0.25 or 0.025 I should say, 2.5 there, beside the plasticage on number one, it's definitely not quite that loose, so we'll come across to our 2000s. |
| 20:50 | And we see that matches quite nicely there. |
| 20:53 | If we try 1.5 thou we can see that the plasticage is not squashed as wide as the 1.5 thou. |
| 20:58 | So, we're at 2 thou on our number one journal. |
| 21:02 | And we can just go through and essentially repeat this process, but going through this, we can see that everything is sitting right on that 2 thou, so the upper service limit. |
| 21:14 | Now, we could go a little bit tighter than that, again I would want to err on the side that's looser rather than tighter, so I'm actually pretty comfortable with that. |
| 21:24 | So, at this stage we've looked at the two different methods of checking our bearing clearances, we've looked at using the dial bore gauge and micrometer for our big end, we've looked at using the plasticage, so irrespective of which method you're wanting to use, you'll know how to go about that. |
| 21:41 | There's one more check we're going to do here that is going to require us cleaning off that plasticage and reassembling our bottom end. |
| 21:49 | This time what we're going to do though is slip our thrust washers into location on number four main and this will allow us to check our end float or thrust clearance in the crankshaft. |
| 22:01 | So, we'll just jump ahead here and this time because we will be moving the crankshaft, it will require the addition of just some clean engine oil to those bearing surfaces to protect them. |
| 22:10 | So, let's jump ahead and we'll have a look at that process. |
| 22:13 | Alright, we've got everything back together, this time with some lubricant on the bearings, we've got the thrust washers now installed in place and you can see we've also installed a dial indicator with a magnetic base located on the snout of the crank. |
| 22:27 | Now, obviously one of the problems with this is that these D2I gauges with the magnetic bases are obviously magnetic and the aluminium block is not. |
| 22:37 | So, a simple trick here is to use a steel plate and I've got one of these with a couple of bolt holes just drilled through it that I can use on alloy blocks to locate these in a variety of locations. |
| 22:49 | So, it makes it quick and easy to get into place. |
| 22:51 | The idea here is we're going to get a couple of flat blade screwdrivers or pry bars for that matter and we're going to simply pry between the crankshaft counterweights and the cradle and we're going to move the crankshaft hard as we can to the front and to the back and that will give us our thrust clearance. |
| 23:08 | Now, the specification for this thrust clearance is a minimum of 4 thou and a maximum of 14. |
| 23:13 | So, it is one of those clearances where there is quite a wide tolerance , but we do need to be mindful that we are within that tolerance otherwise we can end up quickly resulting in a thrust bearing failure. |
| 23:25 | So, let's get our pry bars into location, our screwdrivers into location and we'll see what our clearance currently is. |
| 23:32 | Alright, so pry that all the way back there and just making sure that we've got our D2I zeroed , which we have and now going in the opposite direction and we can see that we've got just on 0.005 of an inch thrust clearance there. |
| 23:47 | It's a good idea to do this a number of times just to make sure that we are getting repeatable results and it does require a little bit of force to make sure that we're taking up all of that clearance. |
| 23:57 | So, at 5 thou obviously we are within the 4 thou to 14 thou range, but we are definitely right on that bottom end of that. |
| 24:07 | However, if you'll recall we did see some marking on the thrust washer that we removed during the strip down. |
| 24:14 | Now, while there isn't any significant marking on the thrust face of the crankshaft, we will have our machinist polish that, so that is likely to potentially open up a little bit of clearance, it won't be very much, but probably get us a little bit into the region, so I'll be a little bit happier with that. |
| 24:30 | We don't really want to be at the bottom end of that range given that we are building up a race engine, it will have a high performance clutch on it that's going to put a lot more thrust loading into the crankshaft than a stock clutch. |
| 24:43 | However, technically we are within Honda's recommended range so that should be sufficient. |
| 24:49 | I've got one last check that we are going to do here. |
| 24:53 | While we've got the crankshaft still installed, this can be done on the bench as well, we're going to check the conrod side clearance. |
| 25:01 | So, that's the clearance between the conrod and the crankshaft. |
| 25:04 | So, this is something that is quite often overlooked. |
| 25:06 | Easy enough here, I've just got the conrod cap or one conrod cap, do this on the number two journal just for simplicity, I'm going to drop that into place here. |
| 25:15 | And what we can do is we can feel that, we can move that side to side and we can see that movement occurring and what we'll do is we'll take our feeler blades here, the clearance recommendation or range here is a minimum of 0.006 of an inch and a maximum of 0.012, again this is a clearance that isn't quite as critical as some of the other bearing clearances, we just need to make sure we are in that range. |
| 25:39 | So, at the moment I've got my eight thou feeler blade and we'll just move the conrod off to the side and we can see that yes we can get our eighth thou feeler blade in there. |
| 25:48 | There's a little bit of friction there so we know that our clearance there is eight thou. |
| 25:53 | And of course it would be recommended to repeat that procedure with our remaining three connecting rods. |
| 26:00 | At this point we've essentially done all of the pre machining checks that we can, everything has really checked out, the only issue or potential issue that we've found is as we've just noted, the thrust clearances may be a little bit tighter than I would like to be seeing. |
| 26:17 | But this is great information that we can then pass on to our machinist and it'll give us an opportunity to look at options to rectify this. |
| 26:25 | So, now it's a case of stripping the engine block back down and shipping it out to our machinist. |
| 26:31 | One point to make here, because this can be a process that could take a couple of weeks potentially, is that we have now removed all of the oil from the crankshaft journals. |
| 26:42 | It's a good idea to spray some lubricant onto those journals just so there's no surface thrust forms while it is in transit or waiting for the machining process to take place. |
| 26:53 | Now, we can move on to the next step of our process. |
