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Old 08-31-2014, 07:48 PM   #1 (permalink)
spectre6000
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Walkthrough: Valve Train Disassembly/Resealing Valve Covers

Say for some reason you think there's an issue with your valve train. Bent pushrod, loose rocker, collapsed lifter, what have you. Alternatively, say you have a leaky valve cover and just want to stop the bleeding. Here are the steps you'll want to go through to get to the root of that problem. Some of this may seem daunting, but I assure you it's a piece of cake. I went from running fully assembled to running naked in a few hours solo. I've done this a few times on this particular engine for various reasons and know my way around and what to expect, so if this is your first rodeo you might allot a bit more time.

Here is the engine I'm working with: a 1984 CUCV, all J-code, all the way with a few minor modifications. If you have a different model or year, be aware that things may be slightly different. Verify things as necessary if there are any questions.



First, remove the air cleaner. All you do is undo the wing nuts (yours will likely be clocked 90 to mine since I have the HMMVW intake), and the whole air cleaner just lifts right off. Set it aside.



Next, remove your CDR assembly. I loosened the hose clamp at the oil filler and at the bottom of the CDR valve itself to keep things as in tact as possible and because it is very difficult with my specific setup to remove the hose at the manifold. There are two 13mm nuts at the base of the CDR bracket and one 15mm nut on the forward #6 intake manifold stud. Set it aside.



Next, since I'm removing the IP anyway (and if you're doing either of the above mentioned projects, you will be too), I loosen the lines at the injectors with a 3/4 line wrench:



As well as loosen the fuel line/wiring harness brackets. There are two nuts holding the brackets to the valve cover studs on each side, both are 13mm. You'll likely need to undo the wiring harness clips to reach them.



Doing this make it easier (in my opinion, at least) to remove the fuel line retaining brackets that are holding the intake manifold in place. Speaking of the intake manifold, there are two 15mm bolts or studs per cylinder. The forward stud on #3 (on the military trucks at least, not sure about the civvy versions) has a nut holding the alternator support brace, and one of the rear studs on the even bank has a bunch of wires attached to it. It's probably worth disconnecting the batteries before messing with wires, so do that, then remove the non-intake manifold things that are sharing studs with the intake manifold. All of these nuts should be 15mm. You'll likely need a combination of deep and standard sockets and a 6" extension to get the rest of the manifold off. With the fuel line brackets clear, the manifold should lift right out. It might be fused to the gaskets or have some sealer on it, so you might find it useful to have a hammer nearby to tap it a bit to get it to let go.



Next, there are two 13mm nuts that will require a deep socket to reach holding the oil filler tube in place. Remove both of these and the filler will pull out from the timing cover through the rubber grommet. If your grommet looks tired, it's cheap and you're already in here, so go ahead and plan to replace it.



For the next step, I found it useful to remove the uppermost part of the fan shroud:



This made it much easier to get a direct line of sight into the oil filler hole to remove the timing gear bolts from the IP. A high tech alternative here that I've used from time to time is to use the camera on my phone. Just turn the camera on and hold it up to the hole, the screen adjusts to the light and is brighter and easier to see, never mind the ability to see around the corner. It also works as a flashlight and a mirror (reverse the camera to the front facing one) as needed (all of this assumes an iPhone, your phone may be different). Freddyack taught me a neat trick for this part to prevent losing the bolts in the engine (no photo because I learned this well after doing everything): get a toilet paper roll and cut a slit lengthwise, stick it in the oil filler hole and tape it to the right diameter (it might be fine as is if you took the grommet out), then cut it to just slightly longer than it needs to be to reach the gear and stick out enough to not lose it; this will prevent bolts from being able to drop into the engine and causing you to have a bad time.



You'll need to turn the crank over (clockwise) until the bolts line up with the hole. The crank turns 2:1 compared to the timing gear, so be ready to crank it. If you're lazy, you'll be fighting the compression; if you're another kind of lazy (or are planning to do something that will require the removal of the glow plugs anyway) remove the glow plugs and the engine will turn over easier. I want to say the crank bolt is 24mm... You'll also want a breaker bar and a bit of an extension here. Someone might need to correct me there on the nut size, I'm typing all of this up from memory. Take the bolts out one by one until all three are in your hand. They're 13mm.



Next, you'll want to remove the three 15mm nuts holding the IP to the block. An open ended wrench is probably going to be your friend here, and be prepared to flip it a bunch to be able to get the angles right. There are better tools for the job, I'm sure, but the wrench has worked for me so far.



The next bit might be a little tricky, but only because there are so many spindly parts to get caught on things. If you haven't already, undo the wiring harness clips in the fuel line brackets, then lift the IP and its lines out in one big spidery mess. You'll find you need to hold it in one hand while you get wires and stuff out of the way, move injector lines around, etc. then change hands and do it on the other side. This is a pretty critical piece of kit, so put it well out of the way somewhere that it can't be stepped on or molested. It needs to stay clean, and it might leak a little diesel, so plan accordingly. I put mine in the very back of the shop on a small dolly so nothing touched the ground and there was no reason for me or anyone else to go back there save to retrieve it.

Maybe I should have said/done this earlier, but put some rags or paper towels down the intake ports so nothing can fall in there. Also do the same to the oil filler holes; be aware that the timing gear is loose in there, so go from the front of the engine first to push the gear back toward its natural position, then, while holding it from the front, put the rags in from the rear. This will keep all the crapnasties where they belong: not in the engine.

Meanwhile, with a deep 13mm socket, remove all of the bolts and studs holding the valve covers in place. Keep track of where they come from, because many of them are required to secure other components, and it will make like much easier when you're trying to beat curing sealant. Again, a hammer might be needed to coax the valve covers free of their sealant, but do your best not to dent them. Freddyack tells me they're minted in unobtainium.



This should be the view currently greeting you. If you're just resealing the valve covers, skip the next parts, clean things up, paint things if you are so inclined, apply the new sealer, and then read the thread backwards (torque specs and tools list are at the bottom of this post).

Meanwhile, if you're looking at valve train stuff, inspect whatever you need to inspect at this point and proceed as necessary.

If you find it necessary to remove the rockers, there are two rocker assemblies per bank. Each is held in place by a 15mm bolt (I understand some things changed later in production; I don't know what those changes are, nor do I have access to such an engine for documentation purposes, hopefully someone can chime in here as appropriate). Undo the bolt and lift the assembly out of the head. Keep track of where they came from as you'll want to be sure they go back in the same location. Make sure everything moves like it's supposed to, isn't excessively worn, isn't broken, etc.



If you suspect bent pushrods, get yourself a good flat surface that can get a little oily. Remove the pushrods one by one and roll them on the flat surface. If they roll smoothly and easily, it's straight. Put it back where it came from and look at the next pushrod down the line. Take note of which end is up, and be sure to replace it in the same orientation. The copper plated end is up, and if that fails, you'll likely be able to see a color difference where the pushrod exits the head.

For this task, I used a tool from my wood shop. It is a piece of scrap from a counter top installation that I got at a building materials recycling outfit for something like $2 that has a curved lip on one end (we call it a bench hook). Granite countertops like this are glass smooth, and the hook allows me to catch it on the end of my bench for sharpening plane irons and such. I REALLY didn't want any gross diesel oil getting to my woodworking shop, so I taped some cellophane to it and used the hook end as an incline so the pushrods would roll down hill.



If you have lifter issues, you could potentially get to a few of them if you're a bit of a contortionist, but you should really consider removing the heads. I didn't have any reason to go this far, so I'm afraid if this is in your future you'll have to get the information regarding rest of the job elsewhere.

For giggles or even more diagnosis information, you can put the IP back on, bleed it, etc. without the intake manifold or valve covers and it'll run just fine. If you rev it too high, it'll shoot some oil out the drivers' side though, so be careful. Don't drive it like this and don't run it for long; it's not super great for the engine when anything can get in the intake or into the crank case through the open heads.

No intake or valve covers - YouTube

To figure out how to put everything back together, read the thread in reverse.

Tools list:

10 mm deep socket (if removing glow plugs)
10 mm socket
13 mm deep socket
13 mm socket
15 mm deep socket
15 mm socket
24 mm socket
1 1/2" extension
6" extension
#2 flathead screwdriver
socket wrench
torque wrench
breaker bar
15 mm open ended wrench
3/4" line wrench
toilet paper tube
shop rags/paper towels
cleaning/prep/paint materials
gasket sealer
something flat

Torque specs:

Rockers: 40 lb.-ft.
Valve cover bolts: 15 lb.-ft.
IP to timing gear: 20 lb.-ft.
IP to engine: 30 lb.-ft.
Intake to block: 30 lb.-ft.
Fuel lines to injectors: 20 lb.-ft.

If there are any corrections or additions, please feel free!

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Old 09-07-2014, 07:57 PM   #2 (permalink)
bobbywalter
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nice how to. thanks for taking the time and pictures. it takes 8-10 minutes to lift my front clip off so i have it way too easy comparatively. getting to my pump gear bolts is a snap.


so you dont do the tdc set and 30 percent turnback to reinstall the rocker tubes with no load??? i take it you never had any issues on reinstall?


dont forget to pull the rags out....i busted one of my rocker tubes and have mismatched setups now....i got the later 6.5 on my 6.2 #6 and 8 from leaving a rag on the intake and starting it like an idi ot. right now i am thinking of freshening up the 6.5 heads and just installing them o the 6.2 and putting a turbo on. the cost of studs is the only hold up at this point.

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Old 09-07-2014, 10:50 PM   #3 (permalink)
spectre6000
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Oh yes! I forgot about that. Glad someone is paying attention. Before putting the rockers on, set the engine to tdc. Once they're on, turn the crank counter clockwise until the notch on the harmonic balancer lines up with the lower right bolt for the water pump (as you're facing the engine). That's how I recall the manual stating it should be done. It was a bit cryptic, but I think that's how I did it. Correct me if that's less than accurate. Assuming my memory is functioning somewhat, that method resulted in no issues.
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