I purchase a 1/4" MIP x 2.5" and a 1/4" FIP x 1/8" FIP fittings from Lowes. Then I cut the 1/4" MIP in half.

                                                 

In order to cut new threads on the fitting, I had to reduce the OD of the fitting by grinding off some of the material. The pic below shows the comparison between one half of the fitting that I reduced the OD and the other half of the fitting that was untouched.

                                                     

Then I used my tap and die set and cut new threads on the fitting. The thread pitch for the oil pressure switch is 1/2" 20-NF. This is the end that will screw into the oil filter housing.

                                                  

With my fitting in the filter housing, I was able to install the tubing for the mechanical gauge.

                                                 

For diagnostic purpose I mounted the gauge in the engine compartment (Sunpro gauge)

                                                 

I think I found why my oil pressure was low. Old fashion engine gunk clogged the pick-up tube.

                                                

Perfect example of a engine that did not get a regular oil change. Varnish.

Before dropping the oil pan I did a compression test. The #1 cylinder was the only cylinder within spec (169-179psi). All the other cylinders range from 190 to 220psi. Due to lack of maintenance, the higher compression readings are probably carbon build up on the pistions

                                              

The next day I decided to pull the heads.

  

 

 

After pulling the heads I pressure washed the heads, oil pan, rocker assembly and oil pick-up tube. Finding a steam pressure washer is a plus, which is what I used. 

 

 

Finish prepping the block. Many cans of brake clean, small wire brush, compress air nozzle, assortment of other cleaning tools and several hours later and this is what I got. I also took the time to chase the head bolt holes with my tap/die set.

 

Re-conditioned the rocker shaft assembly. For those not familiar with the 4.0 lubing system (I'm learning as I'm going) the rocker shaft asssembly is also a passage for pressurized oil. Oil is fed from the head into the rocker shaft stands, through the tube, then into the rocker arms. This is how the contact point between the rocker and push rod is lubricated. Once again there was excessive amount of sludge in the rocker shaft tube and rockers. I disassembled the rocker shaft assemnbly and polished each component seperately. While makeing sure to unclogg the orifice in the rockers.

Took the head apart

 

 

 

 

Got the heads back from machine shop. For $100 it was well worth it. What do you think?

 

 

 

 

 

Also got head gasket kit with bolts.

 

To verify the oil clearance on the connecting rods, I removed the caps and used plastic-gauge on the journals. The specification calls for .001-.002 clearance. It look like I have about .0015, which puts me somewhere in the middle.

All the other rod bearing looked the same like this one, so I safely assumed the clearance where all the same. With the front differential and other steering components in your way, it's not easy laying on your back while removing, installing and torqueing the rod caps. Don't forget the engine assembly lube when re-installing the rod bearings. I then cleaned up the bottom end as best as possible.

 

All eight injectors looked exactly like this one. The tips were clean with no deposits.

Can anyone tell me which way the head gasket goes. There's absolutely no indication on the gasket and all the holes line up either way. When I removed the old gasket, i never thought to pay attention.

 

 

After a little investigating, the pic on the left is the correct side up for the head gasket. The key was the dip stick hole. If turned the other way, the dip stick hole will be covered.

Front crank seal also needed to be replace. Don't forget to clean the harmonic balancer. 120 grit then 600 grit sandpaper will do just fine. Sometimes the balancer gets a wear groove from the old seal. Depending on how deep the grove is will disctate if the balancer needs to be replaced. For now I re-used my balancer.

 

 

 

When installing the head bolts, the manual says tighten the bolts in two stages. Stage I tighten to 20 Nm (15ft lbs) then stage II 180* degree. It's not a good idea to do the 180* degree at the same time. The optimal way is 15ft lbs, 90* degree, then another 90* degree. After tighten to 15ft lbs, I used a center punch to index the bolt head. On this bolt it was index at 12 o-clock, after two 90* degree turns I ended up at 6 o-clock as you see here.

And finally the heads are back on

Cleaning the plenum and throttle body

Before

After

 

Also probably a good idea to get a PCV kit

 

I've always had a slight engine miss, so after pulling the spark plug wire one at the time while the engine was running, it turned out that cylinder #3 was not firing. I first swap spark plug wires, the problem stayed at #3. Then I swap aroud individual coil and the problem followed the suspected bad coil. Hit the internet for a used coil pack. $60 later engine miss gone, all 8 cylinders are firing as designed.

While I was changing the coil pack, I decided to pull all four O2 sensor and cleaned them in the sand blaster. Also installed new copper washers.

 

The fluid in the original clutch had leaked out, causing it to stay locked in. While this may be good for low speed stop and go traffic conditions, it's not good for fuel economy and possibily not allowing the engine to reach operating temp.

 

While changing the hood release cable I decided to look down in between the radiator and condensor. To my surprise I had a nice collection of rubbish. Not a big deal, I removed the upper radiator mounts and leaned the radiator back far enough to clean out the rubbish.

             

 

          

If you have a Disco 1 with a Service Engine Light on, go to Discoweb.org and click on the tech tab for instructions on how to reset the light. The Service Engine Light is a emission reminder light and has no bearing on engine performance. The Check Engine Light is a different story. That light can have an effect on engine performance.

Worn cam lobe

  

                              

    

Oil pump housing/assembly torn apart for inspection and cleaned

     

      

      

                               

 

Wrong lifters -original on riight, replacemnt on left

        

Replacement parts - chain, oil pump kit, crank and cam sprokets

Cleaned and installed

   

 

Correct lifters

         

Pre-lube lifters

    

Earlier when I removed the crank pulley, I knew it had a wear groove from the old seal but I was hoping the new seal would have compensated for the wear and seal the pulley. No luck, the new seal was leaking. Since I've never used a Speedi-Sleeve before, I decided to give it a try. The kit number for the LR is 99192 and I got it from Napa. For what you get the kit is pretty pricey, but it beats taking the pulley to a machine shop to have the turned and sleeved. Installing the kit was straight forward.  and easy.   

   

   

                                  

If your LR ever desides to crank but will not start and you're suspecting it's a fuel delivery problem because you have no pressure in the fuel rail. First, remove the fuel pump assembly access panel in the cargo bay and verify you have voltage going to the pump when the ignition is turned on. But before you go out to buy a pump, remove the entire pump assembly and check the harness connector. This exact scenerio happened to me one morning with absolutely no previous warning signs or driveability issues. This is what I found after removing the pump assembly. The connector to the pump itself was burnt.

So I removed the burnt connector and install appropriate terminal ends.

   

After installing the terminal ends back on the pump in the correct polarity, I cut a piece of fuel hose and place it in-between the terminals to prevent them from touching and blowing a fuse. I also used a small zip tie to secure everything (I forgot to take a picture of that)   

After driving the truck for a couple months, I realized the oil pressure wasn't has high as I would have prefered. So I droped the oil pan to change the rod and main bearings.

   

    

   

And at last, the 5th main bearing. If you forgot to buy new crucifix seals like myself, a little dab of silicone will help. I also put a dab where the rear main seal sits in the bearing cap. 

   

You guess it, I also forgot to buy new seals for the bolts that go into the side of the main bearing caps. Some thread sealant on the thread and under the seals (not pictured)

All in all, rolling in new main bearings wasn't too bad. Laying on my back in the garage is what made it more difficult. If you decide to take on this job, do be prepare to fight with dropping some of the caps. #3 and #5 caps took the longest to drop. Also, if you have a 4.0 GEMS motor like myself, you will have to remove the starter and left exhaust manifold in order remove two of the side main bearing bolts. 

 

R&R camshaft bearings. This time I had to remove the engine.

   

I've always had this annoying engine oil leak that appeared to be a rear main seal. Evident of the read silicone, this camshaft freeze-plug had been removed or reseal before.   It's hard to see from the pic, but there's a little trace of oil coming from inbetween the plug and block. So if your "rear main seal" is leaking, you may want to consider this plug as another possible casue.

 

With the engine removed, I decided to pressure wash the engine compartment, wheel wells and under carriage.

       

Before and after

     

Can someone tell me exactly what these bolts are for? One on each side of the lower engine block. 

       

I then preceeded to mic the camshaft bearings and camshft journal. Without removing the crankshft I'm able to mic number 1, 2, 4 and 5 cam bearings. The 3rd bearing is hard to reach with a telescopic gage.

     

     

Removing camshaft bearings

   

Old and new bearings

   

                 

       

New camshaft bearings installed

      

                                

Removed, cleaned and re-sealed the camshaft plug

        

Rear main seal

         

Ready to go back in