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Practical Engine Building: Step 2: Stripping & Inspecting

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Step 2: Stripping & Inspecting

18.56

00:00 - In the next step of our process, we're going to begin by disassembling our 4G63 engine and our life is actually made a little bit easier here given that as I mentioned, we've purchased this engine in two separate parts so right now we've actually only got the cylinder head sitting on the block, it's not bolted on and we also don't have the rocker gear fitted to the cylinder head at the moment.
00:21 We've also only got two bolts holding the rocker cover onto the cylinder head so we're going to start by removing those.
00:30 With our rocker cover removed we can inspect the inside of the cylinder head and what we're looking for here is a general guide on the condition of the engine.
00:38 As I've already mentioned, this is a low km engine and we can see that it's been maintained reasonably well, given how clean the inside of the cylinder head is.
00:47 This is always ideally what we're looking for.
00:49 On the other hand if we've had an engine that hasn't had regular maintenance and regular oil changes, we're going to find a lot of dark grime built up inside of the cylinder head.
01:00 Doesn't necessarily mean that the cylinder head is not usable but it's going to requite a little bit more work for us to recover it and generally the condition is likely to be not as ideal as what we'd be looking for.
01:12 What we're going to do now is we'll begin by removing the two cam wheels off the front of the camshafts and then we'll be able to remove the camshafts themselves.
01:25 Now we've got our cam wheels removed, we're also going to remove the sensor housings from the back of the camshafts, and these require the sensor plates to also be removed from the end of the camshaft so we'll go ahead and do that now.
01:47 Now we can remove the cam caps, remove the camshafts and we'll remove the rest of the componentry from the top of the cylinder head.
02:35 At this point we've removed essentially everything from the cylinder head and conventionally it would be now time to undo the head bolts attaching the cylinder head to the block.
02:44 In our case, as I mentioned, the head actually was purchased separately so it's not attached, it's just sitting here.
02:50 We can simply lift this off now and place it on our workbench and then we can remove the head gasket.
02:57 Now that we've got the cylinder head removed we can perform a couple of further visual inspections.
03:03 First of all, with the cylinder head we want to inspect the deck surface of the head.
03:07 We're looking for any indications of damage here, any serious scratch or gouge marks, we also can inspect around the outside of the combustion chambers for any indications that there's been detonation or knock occurring.
03:21 In our case, the cylinder head looks pretty much as I'd expect, there's no obvious signs of damage.
03:27 You can also inspect the head gasket and make sure that there's no obvious signs that the head gasket has been leaking.
03:33 All of these can indicate problems that we're going to need to address and rectify when the engine is being machined.
03:39 Once we've got the head removed, we can also inspect the bores and here we can have a look for any sign of excessive wear in the bore, any score marks, any ridging near the top of the bores and any damage to the crowns of the pistons.
03:53 Again, if we're rebuilding an engine, we want to make sure that there is nothing untoward going on, that there's nothing wrong with the tune up that's resulted in a failure of the engine components.
04:05 Otherwise, we can end up rebuilding the engine and find that we're in exactly the same situation a few months down the track when the engine fails again.
04:13 Again here there's really nothing that is a sign of concern, everything's looking really good and in good condition.
04:21 Certainly it's going to be more than adequate for our purposes, given that we will be going to a first oversize in the bores.
04:27 What we're going to do now is flip the engine over on the stand so that we can get the sump off.
04:36 Removing the sump is simply a case of undoing the bolts around the perimeter.
04:40 To speed up that process, we're going to be using an electric rattle gun to do that.
04:45 Once we've got the bolts removed, we will also need to break the seal between the sump and the engine block and this can be a little bit tricky.
04:52 OEM sealant that Mitsubishi use is pretty resilient and makes our job a little bit harder here and it's essentially going to be impossible to remove the sump without bending the sump a little bit where it contacts the engine block.
05:06 We want to be mindful of not doing any more damage than absolutely necessary but it is something to watch because once we have got the sump off, we will actually need to straighten out those edges where we've maybe bent it slightly, otherwise we'll have problems with it resealing once we reinstall the sump.
05:24 To do that, what I'm going to do is use a relatively wide tipped pry bar here and I'm just going to use a plastic hammer and tap that underneath the sump between the sump and the block itself so let's go ahead and remove the bolts to start with.
05:51 I should mention as well, as usual we are packaging all of the removed fasteners into simple plastic sandwich bags and labelling those as we go.
06:00 This is going to make our life a lot easier when it comes to reassembling the engine.
06:13 With the sump removed, this is another good time to have a visual inspection of the condition of our engine and again we can see how clean everything is in our particular example here, giving us a lot of confidence that we have got a good donor engine to be starting from.
06:29 Another thing we would be wanting to look for here if we've got an engine that has suffered from any failure, is there any debris around the oil pickup, have we got any signs of bearing material if there has been a bearing problem? We also want to inspect the crankshaft journals and make sure that we don't have any sign of discolouration, blue or black from heat, that would be a big danger sign that something's not quite right.
06:53 We're now going to strip out the windage tray and the oil pickup, giving us access to the conrod bolts.
07:04 Now that we've got access to the conrod bolts, we're going to rotate the crankshaft, we'll get number 1 and number 4 piston at bottom dead centre, giving us the easiest access to the bolts or in this case actually the nuts that hold the cap onto the conrod body.
07:19 Once those are removed, we will need to break the cap free of the conrod body before we can actually extract the piston and rod assembly out through the bottom of the block.
07:29 And the easiest way to do this is just to use a plastic mallet and a gentle tap onto the end of those studs is going to be sufficient to separate the conrod from the body.
07:39 We want to be very mindful of course if we are reusing any of these components, we don't want to do any damage when we are doing that.
07:46 So let's go ahead and go through that process now.
08:00 One thing to just be a little bit mindful of when we are removing the connecting rods, with a factory connecting rod like this which uses a stud and a nut, we do risk damaging either the crankshaft journal or the cylinder wall as we're extracting the connecting rod, if we end up with that stud dragging against either of those components.
08:21 In our case I'm not particularly worried, we're replacing the crankshaft as we've already discussed, we're already going to be boring the cylinder block so it's not really something that I'm too concerned about however a really easy way of protecting those components is just to use a short section of either fuel hose or large diameter silicon hose and we can simply press that over the ends of the stud and that's going to stay there in place.
08:48 Now as we extract the connecting rod, it's not going to risk damaging either of those components.
08:54 Now we're going to rotate the crankshaft back to top dead centre and that's just going to make it a little bit easier for us to push the piston and rod assembly out through the underside of the block.
09:04 Can be helpful here to use either a pry bar or a screwdriver just to give us a little bit of extension and allow us to push down on the body of the conrod in order to push it out through the block so let's go ahead and get that done now.
09:24 Now that we've got our first piston and conrod assembly out, it's a good chance to take a bit of a visual inspection and see what we're dealing with.
09:32 And for a start, what we can see is we've got these polished areas on the skirt.
09:37 Nothing particularly unusual about that, I would expect to see this in an engine that has been operating well.
09:45 There's no scoring to the skirt though, that's something we definitely don't want to be seeing.
09:51 The other thing to look at is the ring lands as well, particularly with a factory cast piston, if it has been suffering from knock or detonation, it's likely we'd have a section of ring land that may be broken.
10:03 Nothing wrong here and this is also a good time to check that all of our rings are still free in the ring grooves.
10:09 if the piston has been suffering from detonation often this will close up the ring grooves and our rings will be solid or difficult to move in the ring grooves.
10:19 Nothing wrong there.
10:21 Turning the assembly over we also can inspect our connecting rod bearing.
10:26 And this actually looks reasonably good.
10:29 We do see some light scoring and a little bit of light polishing but this would be just due to normal debris that we'd expect to see in the oil so there's no copper showing, there's nothing particularly untoward going on with our bearings so this is what I'd hope to see.
10:46 So what we can do now is carry on and we'll remove the remaining 3 conrod and piston assemblies.
11:14 Alright we've got all 4 of our piston and conrod assemblies removed, it should go without saying here but if we are planning on reusing any of those components then particularly with the conrod body and the caps, we must make sure that these stay together.
11:29 In our case, we're obviously removing all of these components and replacing them so it really doesn't matter for our purposes.
11:36 We can also take the opportunity here to have an inspection on the condition of the crankshaft journals.
11:42 Again in our case because we're swapping to the aftermarket crankshaft, this isn't particularly relevant but what we want to do here if we're reusing the crankshaft is just inspect this, we're making sure that there are no obvious gouges or marks here.
11:55 Basically any scoring that we can feel with our fingernail is a potential sign of a problem.
12:01 This would also show up typically on the bearing so just a double check there.
12:06 The next step of the process, we're going to remove our front oil pump cover, front timing cover and this requires us to also remove the front crank pulley as well as our balance shaft pulleys or assembly as well so let's go ahead and do that now.
12:32 Normally with the 4G63, we should be able to extract the lower cam drive pulley just by hand, in our case it's a little tight so I'm going to just use a puller here to remove it.
12:58 With everything now removed from the front end of the engine, we should be able to extract the oil pump housing from the block.
13:05 Now this will have both of the balance shafts still attached to it so a little bit of care is required here.
13:12 We do also need to break this free of the gaskey that seals it to the engine block.
13:16 Easiest way of doing this is to just gently use a pry bar between the girdle or cradle and the oil pump housing and just gently lever that off the block so let's go ahead and do that.
13:31 For the next step we're going to remove the rear main seal housing off the back of the engine block and this is pretty self explanatory, pretty simple, all we're going to do is remove the 10 mm headed bolts that hold that to the block and again this can often require a little bit of gentle persuasion to remove it from the block using a pry bar just like we did with the front cover so let's go ahead and get that off.
14:07 Alright so we've got the rear main removed from the engine block there and depending on the design of your engine stand, it may actually be difficult to get it the entire way off the rear flange of the crankshaft, it may actually interfere with the engine stand.
14:20 Considering we're about to remove the crankshaft, that's not really the end of the world though.
14:25 If you can't get the rear main seal completely off, I just leave it attached, sitting on the end of the crankshaft and then it can be lifted out of the way when we remove the crankshaft.
14:34 Which brings us to the next step which is removing the crankshaft.
14:37 To do this, we need to start by removing the girdle or cradle that holds the crankshaft in place, just going to clear a little bit more space on our workbench before we get stuck into that.
14:48 In order to remove the cradle, what we're going to do is simply loosen all of the bolts holding it down, we're going to start in the middle and work our way out, essentially the same way we would go about tightening it down.
14:59 I'm going to initially break these free using a strong arm and then we can remove them the rest of the way with our rattle gun.
15:05 Now in our instance, we are replacing these with an aftermarket ARP stud kit so there's absolutely no need to keep these.
15:12 Let's get those removed now.
15:25 With all of the bolts removed, we can now remove the cradle.
15:28 Now this is actually going to be fairly tightly fitted at the moment into the register in the engine block so we're going to need to free that.
15:36 It's pretty easy to do, all I'm going to do is use a pry bar, get that pry bar between the sump rails on the engine block and the underside of the cradle and gently lever that up.
15:56 With the cradle removed, this gives us the opportunity to inspect the main journals on the crankshaft and again if we are retaining the crankshaft, we're looking for any obvious signs of damage, any scoring.
16:06 You can also inspect our bearings and here again we're looking for any obvious signs of damage.
16:12 The bearings here are looking relatively good except for our rear main bearing.
16:15 We can see there is a little bit of polishing noticeable on that.
16:19 Not specifically a concern for us but definitely a little different looking than the other bearings.
16:26 Now that we've got our cradle removed, the next step of course is to remove our crankshaft and to support the crankshaft I'm just going to lift that into the cradle on our workbench.
16:43 With the crankshaft now out of the block, we can inspect the upper half of the bearing shells and again we're just looking for any sign of damage or anything that is obviously going to cause us a problem.
16:54 Now these all look pretty good, we do have a little bit of polishing on our front bearing shell there but not enough that it's a real cause for any concern.
17:02 This is also an opportunity to inspect our thrust bearings.
17:05 Our thrust bearings will still be in the block and on the Evo 5 to 9 the thrust bearings are separate to the main bearings.
17:16 In the 6 bolt 4G63 engines, along with the Evo 1 through to Evo 4 7 bolt 4G63s, the thrust bearings are a full 360 bearing and they're actually integral with the centre main bearing as opposed to separate thrust washers which is what we have in the Evo 5 through to 9 4G63.
17:35 Generally I don't see too many problems with thrust bearing failure in the Evo 5 through to 9 variant of the 4G63.
17:43 There was significant problems with the earlier generations, particularly the Evo 1 through to 4, 7 bolt with thrust bearing failures so it's always a good idea to inspect the thrust surfaces of the crankshaft and also visually inspect the thrust bearings just for any wear.
18:00 It's much better to pick this up now because it may require a replacement crankshaft, than when you've already spent money on machining all of the components and you go to put it back together and find that you've got an issue.
18:12 In this case, everything's looking pretty good, we're going to remove those bearing shells and then we can move on and we can remove our under piston oil squirters.
18:33 Alright so at this point we've got our engine block and all of the components stripped bare, we've inspected all of the components, although in our case, as we've already discussed, we're really only interested in the condition of the bare engine block as well as the cylinder head since we are replacing essentially all of the rotating components.