After reading thru' this, my guess would be lifters.

If you've got a ton of miles, or if it wasn't faithfully maintained, these all-aluminum motors love making sludge, ask your dad.

If you were to spend a weekend on it, you could (as stated previously) pull the pan and clean it as well as the oilpickup tube(I used gas) - pull the valve covers (I believe the rubber gaskets are far better than the OEM corks I used)

Get ready for opinions, I like CD2 (I think) yellow can of detergent booster to gently help clean out oil passages - I, like some others run rotella 15/40 (walmart 15$) in the summer castrol gtx hi-mile 10/40 in winter.

On these, the oil pressure drops in half after warmup, causing low oil feed to lifters - that most likely is the source of your "tapping"

I just replaced all my rod brgs (3hrs from below) and picked up 8-10 psi
(this past year I did everything I suggested, still have minor tappet noise on start)

The sandwich filter adapter I used has (3) 1/8"{npt ports for test ga.

http://www.glowshiftdirect.com/oilfi...-34unf-16.aspx

I used an electic oil press ga. & calibrated it to my (2) mech gauges

luck,greg

 

should I replace the lifters than or is there a way to clean them out?

 

you can try running a Marvel mystery oil mixed with you motor oil and do a couple of 500 mile oil changes.....But remember if you do decide to replace the lifters you must also change the cam

 

Re-read my post above about CD2 detergent - If you replace the tappets, the shop manual doesn't require you to replace the cam unless it's boofed

If you do the stuff I did, you'll at least end up with a cleaner engine

Frequent oil/filter changes will over time (long) help rid the motor of sludge (most common cause of sticking lifter/tappets)

luck,greg

 

If the oil pressure is low can you just change the pump and be okay for awhile? I mean even if there is a knocking sound isn't the damage already done. I noticed my 4.0 has started making a faint knock coming from the lower end.

 

If the lifters require replacement because of wear, then you must replace the cam, or the lifters will be crap within 500 miles. If you are replacing the lifters due to crud/sludge, and there is no wear on the lifters or cam, then you might get away with lifters alone. You may need to replace the rocker arm assemblies as well. Not just the rocker shafts.

 

Chris I think you have it wrong. cam shafts can be reused with no issues as long as you have fresh lifters on them. Once lifters have been broken in they must stay in those specific lifter bores with that specific cam shaft. Of course you can always lap the wear marks off a lifter and reuse them but its not worth taking the chance of not getting them perfectly smooth and wiping out a $200 cam for the price of some $75 lifters But, Im an old hotrodder so manybe Land Rovers use some kinda special cams but I kinda doubt it.

 

If you are replacing lifters from wear, you HAVE TO replace the cam or the lifters will wear out again quickly. If the lifters are worn, then the cam is worn. If the cam has zero wear on the lobes, you can reuse it. That is the only time you can reuse a cam. That holds true on all engines with a cam and lifters.

 

We will have to agree to disagree on this one.

 

Chris-bob is right. The cam and lifters create a specific wear pattern to ech lobe of the cam. If you put fresh lifters on an old cam you risk the chance of wipeing out the lobes on the cam. The only time i would put new lifterns on an old cam would be a roller lifter because in theory there wouldnt be any wear or specific wear pattern. Same goes with a cam you never replace a cam without new lifters youre just asking for problems if you do. I have wiped out a couple cams just replaceing lifters in them, each one lasted about 500 miles so dont be cheap if you do change out that stuff.