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Practical Engine Building: Step 2: Stripping And Inspecting

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Step 2: Stripping And Inspecting

31.26

00:00 - In this step we're going to be disassembling our SR20 DET donor engine.
00:05 Now we do only have a short block here since we are using the P11 cylinder head.
00:10 So this takes away some of the work, we don't obviously need to strip the existing head off the block.
00:16 The engine that we are dealing with is a little bit dirty and one of the aspects that we do need to keep in mind is the condition of the components that we will be retaining.
00:25 In this case relatively straightforward, we will only be using the bare block and the crankshaft.
00:30 We are also over boring the cylinders.
00:33 So while we have got some water damage present, particularly in number one cylinder, this isn't a big concern because we'll be able to clean these up with a bore and a hone.
00:43 So let's get started here by removing our sump.
00:46 The first section of the sump we'll remove is this steel pressed lower portion.
00:51 One of the things we want to look at here as well is any sign of damage on the sump pan.
00:56 This is a good thing to look at when we are considering purchasing a donor motor.
01:00 One of the quite common reasons for failure is where something has been hitting against this pan and bashed it up against the oil pickup.
01:07 This can restrict flow into the oil pickup.
01:10 In this case we do see we've got a dent here.
01:12 I'm not too concerned about that, it's away from the oil pickup, and we will actually be replacing this lower pan with a larger winged sump.
01:20 So let's get started with removing that.
01:38 Once we've got all of our bolts removed we then need to break free the silicon seal between the lower pan and the rest of the cast aluminium sump.
01:46 Now this can be a little bit tricky.
01:48 In our case, prior to purchasing this engine we actually had one of the bearings inspected to make sure that it was in good condition so this has already been broken free.
01:57 This makes our job a little bit easier.
02:09 With our lower pan removed, this gives us access to our oil pickup and a windage tray.
02:14 We need to unbolt all of those components next.
02:28 Now we can go ahead and remove the cast alloy section of the sump and this simply requires us to remove all of the bolts around the outside of the sump.
02:37 We also have a series of bolts that are accessed through the inside of the sump, so we'll do that now.
03:25 We've gone through and removed all of the M8 bolts around the outside and the inside of the sump.
03:30 It is important though to remember that there are also two M6 studs right at the back of the block that also need to be undone so we'll take those out now.
03:49 With all of the fasteners removed from our sump we can now break the sump free of the engine block.
03:54 Again typically the silicon makes this a pretty tricky job, although in our case the sump has previously been removed so this is going to be pretty straightforward.
04:03 Now if your sump hasn't been previously removed, this is an area where it is possible to do a reasonable amount of damage, albeit probably only cosmetic, to the engine block and the sump.
04:14 Because they are aluminium, it is quite easy to dent or mark these.
04:17 Typical way that most engine builders will disassemble this is to get a pry bar or a screwdriver or something of that nature, physically fit it between the engine block and the sump and try prying it up.
04:29 Now we need to do this with care because the cast sump is quite fragile.
04:34 And if we pry it up too vigorously, it is possible to crack or break the sump.
04:39 The other thing this is going to do is leave marks on both the sump and the engine block.
04:44 Now a little known fact with the SR20 block is that Nissan thought ahead with this.
04:49 We have two threaded holes at the back of the sump.
04:51 So we can take fasteners and thread these into the holes, and by tightening these down gently against the block, this will actually lift the sump off the block.
05:01 Now in our case, everything's already quite loose so I'm just going to take our pry bar and we're going to gently lift that sump up and remove it from the block.
05:15 So this gives us access to the crank case of the engine.
05:18 We can now see a little bit more about what we're dealing with and we can see that this engine probably hasn't had the best maintenance regime in the world.
05:27 There's quite a lot of varnish and gum in here.
05:30 That's not necessarily going to be a problem for our purposes though.
05:33 We've got a couple more bits that we're going to remove here, we're going to remove the oil pickup and we've got another small section of windage tray that's going to allow us to get access to the connecting rods so we can remove the conrod and piston assemblies.
06:13 Before we move on, with all of our fasteners for the sump, windage tray, and oil pickup now removed, it's a good idea to collect these all together and store them so they're not going to get lost.
06:24 So we've got a sandwich bag here that I've already marked with sump, and we're going to put all of our fasteners into this.
06:33 Now we can loosen our connecting rod big end bolts.
06:36 Now at the moment we've got number one and number four piston and top dead centre.
06:40 So we've got access to number two and three.
06:42 It really doesn't matter what order you go through and do this in.
06:45 So we're going to start with number two and number three.
06:48 What we do need to do though is rotate the crankshaft slightly so that we've got access to both bolts for our connecting rods and at the moment we can see that two of the bolts are hidden underneath our girdle.
06:59 So let's do that now.
07:09 Our conrod bolts are likely to be reasonably tight so it's a good idea here to use a strong arm to crack them off.
07:22 Once we've got those nuts initially cracked off, we can remove them the rest of the way.
07:35 With those nuts removed we still can't remove the cap from the connecting rod body because the cap is locked into the register on the rest of the connecting rod.
07:42 In order to remove this or break free the cap from the rod body, what we can do is just gently tap down on the end of the studs in the connecting rod body using a small punch and a gentle tap with a hammer.
08:04 Once we've got the caps free of the register we're able to remove them.
08:08 Now it is important, particularly if you are going to reuse these rods, to make sure that the cap stays with its respective connecting rod.
08:21 It's always a good idea when we are removing the connecting rods, just to inspect the bearing shell.
08:26 And what we're looking for here is any sign that the bearing shell is damaged, any scoring or any sign that the copper from the underside of the bearing shell is starting to show.
08:37 In this case the bearing shell actually looks in really good condition which bodes well for the rest of our crankshaft.
08:49 With our connecting rod caps now removed, I'm going to rotate the crankshaft through 180 degrees, bringing pistons two and three to top dead centre and from here we're gently going to be able to push them out through the top of the block.
09:24 With our number two and three piston and connecting rod assemblies now removed from the block, we're going to repeat the process that we've just looked at, for cylinders one and four.
10:04 With our piston and connecting rod assemblies now removed, it's an opportunity for us to have a quick visual inspection of our crankshaft journals.
10:12 Not gonna get too fussy with this right now because we're going to be able to inspect them much more closely once we've got the crankshaft out.
10:17 But at this point we can note that there are no scores that we can feel on those journals with our fingernail.
10:23 This is obviously a good sign as it means there's a good chance we're going to be able to reuses this crankshaft.
10:29 The next step will be removing the front crank pulley, the front cover assembly and oil pump as well as the water pump assembly and then we'll be removing the rear main seal from the engine block.
10:41 Let's start with this crank pulley though.
10:50 In this case we've been able to remove our crank pulley bolt just using an electric rattle gun however sometimes these crank pulley bolts are going to be a little bit more stubborn and there's a couple of options you can go through here.
11:01 If you've still go the flywheel attached to the end of the crankshaft, you can lock the flywheel ring gear up to prevent the crankshaft rotating.
11:09 This will allow you to get in there with a strongarm and potentially even an extension to crack that crank pulley bolt loose.
11:16 The other option if we've got the sump off like we have here, is that you can physically lock the crankshaft and prevent it moving by using the end of a pry bar and just locking that between the outside of the engine block and one of the crank counterweights.
11:29 If I'm gonna do this I make sure I use the plastic end of the pry bar.
11:32 This way we're not going to end up potentially damaging either the engine block or our crankshaft counterweight.
11:39 With our crank bolt now removed we need to remove our crank pulley.
11:43 Sometimes these will come off relatively easily, other times like this one here, we are going to need to use the puller.
11:50 If we're going to use a puller, we want a three jaw puller, and it is essential to understand where we're going to be locating that puller.
11:57 This is a harmonic dampener so there is a rubber piece that separates the inner from the outer of our crank pulley.
12:03 This means that we want to be using our puller on the outside of this section of our crank pulley.
12:10 So let's get that done now.
12:13 Before we can fit our puller, we're also going to take our crank bolt and just wind that back in a few turns and this will give us something to locate our puller on.
12:21 Let's get our puller fitted up now.
12:30 Alright we've got our puller located there, we've made sure that the jaws of our puller are located on the outside of our crank pulley and we can now tighten the puller and this will remove that crank pulley off the snout of the crankshaft.
12:52 We'll get to a certain point where that pulley has actually come loose, we won't need the puller anymore, we can remove our crank pulley bolt again and we should be able to remove the pulley the rest of the way by hand.
13:08 With our pulley now removed, we're going to be able to remove our front cover assembly, so we're gonna go through and loosen all of those bolts, gently pry that front cover off the rest of the engine block, and we'll also remove our water pump while we're at it.
13:29 Once we've got all of the bolts removed, we're going to need to break that silicon seal between our front cover assembly and our engine block, and this can be a little bit tricky.
13:38 What I'm going to do here is use a pry bar and we're just going to be gently prying between the front cover and our front main bearing cap.
13:55 With our front cover assembly removed, we've got access now to our cam chain, we're going to be able to remove the chain as well as the chain guide assembly.
14:03 So let's do that now.
14:21 The chain guides in particular are one of the components in the engine that does wear and these would normally be replaced during an engine rebuild.
14:28 In particular on these guides here, we can see some reasonably obvious signs of wear.
14:33 So we will be replacing these when the engine goes back together.
14:37 Likewise we also want to consider our cam chain.
14:39 And while the cam chain doesn't wear out or stretch as easily or quickly as a cam belt, in this instance we will be starting with a brand new cam chain.
14:57 With the front of our engine now stripped down, we can remove the rear main seal, and this will give us access to allow us to remove the crankshaft from the engine block.
15:25 Just like our front cover assembly, once we've got all of the bolts out of our rear main seal housing, we need to break that housing free of the silicon between the housing and the engine block.
15:34 This can be done with either a large wide flat bladed screwdriver, or a small pry bar, and again we're just going to pry between the cover assembly itself and our rear girdle.
15:54 Once we've got the housing free of the two dowels that locate it, we will be able to remove it off the end of the crankshaft.
16:04 Now with our rear main seal out of the way, we can actually remove our crankshaft and this starts with us needing to undo all of our main bearing cap bolts.
16:14 So we're gonna start in the middle here and work our way out.
16:57 Once I've got all of those bolts initially cracked off by hand using the strong arm, I'm going to go through and remove them the rest of the way using our rattle gun.
17:17 With all of our bolts removed we can now simply lift the girdle out of the way and this will reveal our main bearing caps.
17:25 The next task is to remove our main bearing caps from the register in the engine block and this can be a little bit tricky, they can be stuck in there pretty tight.
17:33 You'll notice there is actually a threaded hole in the top of each of these caps, and this is designed by Nissan to allow us to use a slide hammer in order to pull these caps vertically up.
17:43 Another technique we can go through if we don't have a slide hammer, is to rock those caps backwards and forwards and this will in time free them from the register.
17:51 What I'm going to show you though is a little cheat if you don't have the slide hammer.
17:55 What we're going to do is take a threaded fastener, we're going to thread these into the caps, and then we're going to use a pair of pry bars in order to pry that cap vertically up.
18:05 So we're just going to thread that down into the cap, once that's located there we're going to get the pry bar under both sides of the head of that fastener and we're going to pry off the rails on the side of the engine block, so let's do that now.
18:25 So with just a small amount of pressure upwards on those sump rails, we can pull that cap out of the register in the block, I'm gonna go through now and we're gonna complete that with the rest of our caps.
18:41 So we've got all of our five bearing caps removed now.
18:44 It is important to remember that these caps need to be kept in order, although Nissan make our life pretty easy here because they do have a stamp number on the top of the cap, making it pretty much impossible to put them in the wrong location when reassembling the engine.
18:57 As usual when we're removing the caps, we also want to inspect the condition of the bearing shells, and in this case despite the engine having an unknown origin, the shells actually are in reasonably good condition.
19:09 What we can see is that on our centre main bearing, there is some light scoring present and there's definitely a little bit of wear showing which would be in line with the engine having high mileage.
19:20 What we want to do though is also check and see if there's any matching damage on our crankshaft journals, and in this case in particular, our centre main journal is showing no sign of any scoring, so it looks like that damage is only present on the bearing shell.
19:34 With our shells out of the way, our caps out of the way, we can now remove the crankshaft out of the block.
19:50 With the crankshaft now out of the block, we can also inspect the upper bearing shells.
19:55 Although there is less load applied to these upper bearing shells, so if we aren't seeing anything untoward going on, in the bearing shells in our main bearing caps, it's unlikely that we're going to see any serious damage that's a surprise to us on the upper bearing shells.
20:09 Let's take a look though.
20:16 In this case for the most part our bearing shells do look quite good for a high mileage engine, with the exception of the polishing that we can see on our front and also our rear bearing shell.
20:27 In particular on the front we can see that it is actually starting to show copper on that bearing shell so if this engine was run for much longer it's likely it may have ended up suffering from a bearing failure.
20:38 For our case though, there's nothing here that shows any sign that we can't continue with the components that we've got to deal with.
20:46 Now we're gonna go ahead and remove those bearing shells from the engine block, and this can be done just with simple pressure from our thumbs down on the bearing shell, the side opposite to the locating tangs.
20:56 So let's go through and do that now.
21:10 We also want to remove our thrust washers which are on our centre main.
21:14 It's also a good idea to inspect the surface condition of the thrust washer on the side that is loaded when the clutch is disengaged.
21:23 In this case we can see that there is some light scoring on this thrust washer and it's also discoloured a little bit, it is showing a bit of a copper colour, so this shows that there is some reasonably significant wear on the thrust washer.
21:36 We can also confirm this and make sure that this hasn't resulted in damage to the thrust face on the crankshaft.
21:43 This is a good time to stop and have a look at the differences between the SR20 DET main bearings that we've just removed and the GTIR bearings that we're going to be fitting.
21:53 Now we've got one of our GTIR bearings here and we've got our SR20 DET bearing.
21:59 Now we can see that there are two oil slots in the GTIR bearings, compared to one bigger hole and another very small hole in the stock SR20 DET bearing shell.
22:12 So the GTIR bearing shell allows superior oil flow through onto the crankshaft so this is the advantage.
22:18 However to take advantage of that, what we do need to do is have some grooves machined into the engine block so that oil can actually flow to both of these slots.
22:28 If we install our bearing shell into the block temporarily, we'll see that the second slot is completely blocked until we make those modifications.
22:37 So as we can see here without some machine operations on our SR20 DET block, the GTIR bearings are not going to be an advantage to us.
22:46 Next we're going to remove our under piston oil squirters from the engine block and this can be done with a 10 millimetre multihex socket.
23:03 At the same time we've also got a little plate that bolts into the engine block and I'm going to remove that as well.
23:30 So at this point we've got just about everything removed from our engine block.
23:33 We're now going to flip the engine block over and we've got a few ancillary components on the outside of the block that we're also going to remove.
23:41 On the exhaust side of the engine block we simply have our turbo oil feed supply to remove.
23:46 This has actually been damaged by the wrecking yard this engine came from, but we are going to be potentially reusing the banjo bolt.
24:05 We can now flip the engine block over the other way and we're going to remove the oil filter housing assembly.
24:25 So we've got our oil filter housing removed from the engine block, and in our build we're actually going to be replacing this with an aftermarket housing that includes take offs for our oil cooler so we're not going to need to keep that.
24:37 So we're at a point now where our engine block is stripped bare and we can essentially send it off to our engine machinist.
24:43 Before we do that though we will just touch on a couple of areas that we want to inspect on the engine block, just to make sure that it is suitable for our rebuild purposes.
24:52 With an engine that's been received from a wrecking yard like this with the cylinder head already removed, one of the aspects we want to be careful of is to make sure that there's no sign of any significant damage or marking on the deck surface of the engine block.
25:06 While we will be going through and having our engine block decked by our engine machinist, this only takes off a few thousandths of an inch of material.
25:14 So it's not going to be enough to remove serious marking.
25:17 And if we need to machine a lot of material off the block, this is going to affect our piston deck height and potentially also our clearance between the top of the piston and the cylinder head as well as our compression ratio.
25:29 So it's a good idea to make sure that we are starting with a deck surface that is in good condition.
25:34 We've already discussed the fact that for our particular build we are moving to a first oversized piston so for us the bore condition isn't overly critical.
25:43 However particularly if you are retaining a stock bore diameter and you're only intending to have the bores lightly honed, it's a good idea to make sure that there's no corrosion or any marks in the bore that aren't going to clean up with a light hone.
25:58 In this case, particularly in cylinder number one, we can see that there is signs of some light corrosion damage, we've obviously had some water sitting in this bore at some time.
26:07 For our purposes though because we are going to be boring that cylinder half a millimetre oversize, that's definitely going to clean up so I'm not concerned about it.
26:16 At this point we're done with our cylinder block, but we're also going to have a slightly more detailed look at some of our other components.
26:24 At this point we're going to spend a little bit of time and take a closer look at some of our engine components.
26:29 And it's important here to inspect everything that we've got that we're going to be delivering to our engine machinist so that we can avoid wasting time if there's any problems with the componentry.
26:39 Let's start here with our crankshaft as this is one of the components aside from the engine block that we will be reusing.
26:46 As we've already seen, it appeared that our crankshaft was in pretty good condition, and in particular what we want to do is take special note of the condition of all of the journal surfaces.
26:56 What we're looking for here is any serious damage or scoring and in particular, anything that we're able to feel with a fingernail.
27:04 This would indicate that the journal possibly may need a grind.
27:07 In this case, despite the high mileage, the journal condition is actually really good.
27:12 We've got some light scoring visible but nothing that would require anything more than light polishing.
27:19 At the same time we also want to carefully inspect our thrust surface on the crankshaft.
27:23 Again what we're looking for here is any sign of scoring, and if there's damage to the thrust surface that is overlooked, it can really quickly destroy our brand new thrust bearings.
27:33 Again everything in this case looks pretty good.
27:36 Now our crankshaft itself is quite dirty which is typical for a high mileage crankshaft, particularly in an engine that may not have been looked after that well with regular oil changes.
27:46 But more concerning we can see that there is some corrosion present on some of the crankshaft counterweights.
27:52 Now this actually isn't going to be an issue, this will clean up.
27:56 However it is a good idea if we have corrosion present, particularly if the crankshaft has been stored outside of an engine for some period of time, we'll also want to check very carefully in the chamfers or radius between the crankshaft counterweights and the bearing journals.
28:13 If we've got any corrosion present in these areas, it can become a stress raiser and it can end up leading to cracking later on.
28:20 So at this point we've inspected our crankshaft, we know there's no obvious problems with that crankshaft, we should have something that our machinist is going to be able to work with.
28:29 We'll move on and we'll inspect the rest of our components.
28:32 The next component we're going to inspect here is our engine bearings.
28:37 And in this case our engine bearings are delivered in nice cardboard boxes.
28:40 So this makes it pretty obvious if there's any chance or likelihood of damage, we should see some impact damage to the boxes, and in this case everything looks fine.
28:50 We can also remove our bearings from the box and these particular bearings come really nicely packaged as well, they come on a little tray and they are wrapped so that they can't bang into each other or become damaged during transit.
29:03 The next component we're going to have a look at here is our connecting rods.
29:07 And what we're looking for here is any obvious signs on the connecting rod surface that it has been damaged by either knocking against another conrod or maybe dropping off a work bench.
29:16 The conrod surface is obviously quite hard, being that it is a steel alloy, so it's not always going to show up any obvious signs, but a careful inspection of the surface of the rod is about all we can do at this point.
29:30 In a similar way we also want to inspect the condition of our forged pistons.
29:35 Now here because these are an alloy piston, these will show up any marking on their surface really easily, so we're inspecting the condition of the skirt, as well as the ring lands and the crown of the piston, looking for any sign that they've been dropped, marked, scored, or otherwise damaged.
29:52 At the same time when we are going through and inspecting our pistons, it's a good idea to make sure that our box does contain all of the components that we need.
30:01 In this case we're looking at our ring pack.
30:04 We've got that sitting here.
30:06 We'd want to also make sure that we do have enough rings in our ring pack.
30:09 We'd also want to make sure that we've got all of our wrist pins and we'd want to make sure that we have sufficient wire locks as well.
30:17 It's always a good idea to find out if we are short on any components right now before we get to a point where we're trying to do our final engine assembly.
30:25 A point that I'll make with all of the components that we have just looked at as well, is that we want to make sure that the part numbers that we have delivered, do match what we're expecting.
30:34 This can save a lot of wasted time and effort if we find out later on down the track that we've actually got the wrong pistons for example.
30:42 The last component we're going to inspect now is our Tomei multi layer steel head gasket.
30:48 Now the head gasket from Tomei does come very well packaged so it is pretty well protected.
30:53 But it's always a good idea to inspect the surface condition of the head gasket, we're looking for any signs that the head gasket has been bent in transport or any signs that something sharp has damaged the surface condition of the gasket.
31:06 In this case our gasket is in perfect condition so we can be comfortable when we go to install that.