For now I decided to pull the heads. The rockers arms and valve covers are pretty much what I was expecting, more sludge.






The pistons and combustion chamber wasn't as bad as I was expecting. Look quite normal for a high mileage engine




What I was pleasantly happy to see is trhe cross hatch pattern on the cylinder walls



I thought these engines had cylinder liners. It looks like a regular block to me. Or was it the 4.6 that had liners?

 

Today I took my parts to get pressure cleaned. Finding a pressure cleaner that alsoproduces heat is a plus, which is what I used. I got alot of the heavy gunk off, but I'll probably try to clean them some more



The rocker assembly come out ok, but this is one item that i'll be definately cleaning some more



I never took any before pics of the valve cover, it was in the same condition like the oil pan and rocker assembly


Oil pick up tube, I can actually see through the screen






Now that i can see everyhting clearly, it's time to order replacement parts

 

Slow but steady.

Today I finish prepping the block. Many cans of brake clean, small wire brush, compress air nozzle, assortment of other cleaning tools,several hours later and this is whati have.I also took the time to chase the head bolt holes with my tap/die set. All but 2-3lifters appeared to still have their spring tension when I push the plunger down with a screwdriver. I'll take a closer look at all the lifters that didn't move with the screwdriver test before putting it back together.





Now to start prepping the heads, see you later.

 

Wow. What a difference. I WANT TO LEARNNNN

 

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.

 

You're doing a great job! I haven't seen an engine that gunked up in years. It was something else! The combustion chambers and cylinders look good, but the one in the close-up appears wet, oilyand particularly caked up. When you see that, you have to question why it's more wet and caked up and not dry like the others.I wouldinvestigate forafaulty injector, cracked oil or compression ring ...or really worn valve guide. Was there a lot of blow-by on that engine before you took it apart? If so, could have been coming from this cyl.

You didn't mention it, but my personal plan of action is whenever I remove the heads from a high-mile vehicle I always take them in and have them tanked,checked for straightness, valve seats re-ground and valve guides checked/replaced (where necessary). The efficiency improvements of a fresh 3 angle valve grind (properly done) is well known. I think you stand to gain a lot from it, given your vehicle's mileage.Should run about $150-$200. Then you get back heads that are fresh and good as new. And heads are the make/break part of your engine's air flow system.I'd almost be tempted to pull that piston out and check the oil ring for being cracked. I mean, it's a high-mile engine, isn't it? I now it's a lot of work, but you're almost there. Any thought aboutpulling the block at this point and sticking in new rings, bearings and cam/lifters?

 

Since thecompression readings were allabove spec, theplan is toonly do a top end recondition. Yes it's a high mileage engine that wasn't properly maintained. As far as I can tell, the biggestissue with this engine was the lubing system. Granted the lubing system is the life-line of any internal combustion engine, and a engine with a bad lubing system usually doesn't end well.I waspleasantly happy to see my compression readings above spec. Ideally I would have prefered to do a leak down test, but I got anxious and started pulling the heads after the compression test. None of the cylinder walls showed any sign of scoring, and with the compression readings I cansafely assume the rings are good and not crack or sticking. As a matter of fact, after I finished cleaning the block and pistons, I sprayed a liberal amount of penetrating oil into each cylinder. My intent was to keep everything nice and lube until the heads went back on.The next day after spraying the penetrating oil, there was still a small puddle of oil on top of each piston.This indicated to me that very little oil was able to leak bythe rings overnight, which is another sign of thecondition of the rings.Maybe I'm holding on to wishfull thinking, but from my experience it appears this short block is good. So to answeryour question, would I consider pulling the block for a bottom end rebuild?At this point I will not. I'm also not totally donewith the block. My intent is to pull each lifter and take them apart to make sure their not sticking internally.

You're on track when you mentioned that one of my combustion chamber looked oily and caked up. Since taking the pics I can't remember which cylinder was the oily and caked up cylinder, but I can tell you my #3 spark plug was extemely foul and carbon up. Which would cause unburnt fuel to collect in that cylinder. Even the exhaust manifold port for that cylinder had excessive carbon. While the other 7 exhaust ports looked normal. To answer your other question, was there alot of blow-by. There was no blow-by.When I first looked at the truckin the company parking lot, that was one of the key items I looked for when the engine was started for me. With a cold engine I looked for signs of burning oil in the exhaust, there was none. I also smelled the exhaust to see if there was any signs of coolant or any other abnormal exhaust smell, there was none.I probably will take your advice and plasti-gauge a couple of connecting rod caps.But I am having difficultyfinding the torque specs in the CD manual. If I can't find the torque spec, I'll probably use a generic torque based on the size of the cap screw/bolt.

I totally agree, a good flowing head can be amake or break deal. My intent for the heads is to check eachvavle guidewith a dial indicator. Depending on how much movement I have on each valve,that will give me a general idea of the condition of the guides.After checking the valve guides, then I will look at thevalve face and seat.If the valve face and seat have pits or show signs of not sealing properly,I will first attempt to re-lap the valves myself with lapping compound.If all the above turns out good, I'll add new vavle seals and call it a day. I've done this method on other heads with good results, but it all depends on the condition of the heads.

 

Mike,

It might just be a bad plug, or wire at that cylinder too that caused it to be fouled out. Always look at the simple things first, right? But if you're going to pull a rod bearing and plastigauge it, how about doing that piston? Just pull it out, if you determine ahead of time you can.Ya can have a cracked oil ring or lower ring and not know it other than some oil usage,which I would hate to see you find later on.

Back to the heads, I think it's great you are giving each component proper attention. Hopefully you'll benefit by having a nice running engine when you're finished. But ask yourself, is going through the effortofremoving the valves,cleaning the bottom of the valves and theseat area, checkingvalve guides/seats, lapping themand all that, ... on a pair of heads with 150k miles, rather thanhaving themall hot-tanked,inspected for straightness or cracks, checking the springs for proper tension, aquality 3-angle valve grind (which any racer or mechanic will tell you is one of theBEST things you can do), is spending a couple days or whatever doing all that and still having 150k valve seat wear going to be worth savinga couple hundred bucks?I could see it if they only had 40,000 miles on them. Plus,lapping the valves on a pair of headswith the mileage yours has would be considered very 'shade tree' practice among any goodmechanic's judgement.You're just not going to get the performance benefits ...and in fact, you could even go backwards a little. If I had compression variance, that would be just one more reason to have the heads and valves re-done.

Don't get me wrong,I think what you're doing is great, but as a fellow 98 Disco owner, I want to see you get the most out of yourhard work. In a couple years, you might be getting close to the 200k mi mark. If the heads are done right, now, it'll still be running top notch and your investment will have paid for itself.In mathmatical terms, if you end up getting.5 mi per gallon more in MPG due to a good head reconditioningin 20k miles @ $3.75/gal you'll earn back $161.28. At leasttake a few minutes and make a couple calls to local machine shops andget ball-park pricing on getting them re-conditioned.

Keep the pictures and adventures coming, man!

Mark G

 

Today I tore down the heads. Valve guides all checked good, not worn. The heads and valves needmore cleaning before I can decide what to do next.













A lot of carbon that can be easily cleaned up, it's not as bad as it looks.

 

So I decided to bring the heads to a machine shop. For $100 it was well worth it.It's not a multi-angle valve job, but it will definately get the job done.













Also got a gead gasket kit with bolts


Can anyone tell where these o-rings go?Are they part of the intake manifold/plenum assembly? Or is this kit also for other Land rover models?


The next step is to clean up the garage, tools and work site. Have to make sure the engine is re-assemble in a clean enviorment. Once that's done then I drop the rod caps for a close inspection.

See you then