Originally Posted by Best4x4

I have never been light on the throttle on any of my vehicles. I will rev my 235K Kalahari up to 4.5K no problem. If I am going to own something I am going to use it. I keep up on all the fluids/maintenance, I am very in tune with my vehicles, and I can feel the slightest thing or thru throttle input I can tell if something is off.

When I have people over that I'm working on their LR's sometimes we take one of mine into town if we need something. They are usually pretty quiet and when I we get back they all pretty much say the same thing like "man I wish my LR ran like that" or "that is the best running 4.0L D2 I've ever rode in". All I can say on that is I learned everything I know from my two best friends with over 25 years of LR experience each. I was 15 when I fell in love with these things back in when my mom had an 89 RRC. I saw plenty of blown up engines, D2's that jumped off small cliff's, and vehicles that people owned that didn't even know where or what the hood latch was for (and it showed...). I have owned over 20+ LR's to date and honestly not a single Rover 3.9/4.0/4.2/4.6L engine has ever let me down! I have had axles snap, alternators die, and plenty of other goofy things happen, but I have always made it home.

These engines are NOT as delicate as people make them out to be. The sad fact is some rolled off the assembly line crappy due to the Brits & Germans not always getting along on the assembly line, tooling for the engines got worse over time, and then finally a lot of the LR's running around were not maintained by people with a lot of knowledge. I've been lucky to have bought 20+ LR's that were well kept by their owners. Keeping them cool, and full of fluids is key to any engine, but with a LR engine it's critical. I've seen so many people spend 1500.00 on a HG job only to overheat either on the way home or shortly thereafter because they DID NOT actually fix the cause of the problem. The HG's were the end result, but almost every one I've looked at that just had a HG either had the original water pump, radiator, coolant hoses, or thermostat....... You can not blame the engine for that!

I bought one 02 D2 from a guy and he said he changed everything out. I was in a rush to pick it up and I forgot my scangauge II when I was dropped off to get it. I drove it 2HR and little did I know yes he replaced a lot of stuff, but the completely clogged and rusted thermostat was still in it and I was running 230F all the way home...... I quickly changed out the thermostat to a 180F unit and my temps never went above 206F in stop n go traffic after that. Now when I look at LR's I honestly don't even look at anything with less than 150K on them. It's the 150K and up vehicles I look at. Those are the ones people have maintained and it shows.

Each one I've looked at I've dropped into 1st gear and left it there and driven it up to the rev limiter. I look for black smoke, and I watch the engine temp, and listen to the engine. If everything looks good I'll buy it. If something doesn't add up I usually pass. If the owner won't let me test it like that = I walk

I personally prefer the 4.0L engine. The 4.6L to me was just to much blood being squeezed out of a turnip & LR was already getting ready for the LR3 and the end of the Rover V8 so they had absolutely no plans to fix it. Making it run hotter for emissions was the final nail in the coffin, and the 180F thermostat should have been factory vs used years later.

I sound old when I think back how long I've been messing with these things, but I love every single minute of it. My latest project has been the 97 XD that I saved from just barely running around on a ranch in TX rusting slowly away (the cancer is severe), but I took a vehicle that hadn't been out on the road in years, and after 4 months of working on it = it's now cruising down I-10 at 70-85MPH (I got up to 80-85MPH for testing purposes). The engine needed serious TLC. The previous owner did some stuff very well like a new $$$ Nissens radiator, but then did other stuff really cheap. It got a complete tune up, new coolant hoses, new water pump, new 180F thermostat, new coolant, and I fixed the AC which the previous owner said hadn't worked in 6 years by simply replacing the A/C on/off button and the blower slider. Then I finally tracked down it's awful running to an ECU that looked like Jack Dawson from Titanic took down with him to rest on the ship. It was badly corroded and 6-10 traces were complete done for. One of those LR buddies I mentioned earlier tracked down a 96 ECU and matching alarm box, and now it runs excellent. It has power, idles properly, and I'll be at the 2019 HCRR in it. Only thing left on the list is larger 235/85R16 tires. The XD will never be perfect cancer wise (needs a new body honestly), but I will probably totally restore that one day with a donor body. However mechanically she is solid and I'll be driving it 10HR roundtrip in Oct not counting cruising around Austin for a few days.

The good news is now days there is a lot of knowledge thanks for forums like LRF and you can modify and upgrade your Rover V8 in many ways to make it last longer (cooling and other improvements like PCV mods and several other things). 93 octane fuel is awesome, but these things will not just die with 87 in them. Less HP maybe, but the Bosch setup was the best of the best Rover V8 management wise. When I towed home the XD from College Station with my 99 D2 I was going highway speeds and up/down hills. I watched my Scangauge II like I always do and the temps were spot on 193-202F for the entire 3.5HR trip home. I've made that trip without a D1 strapped behind me and the performance was just about the same minus the braking lol.

Originally Posted by 05TurboS2K

I wonder, has anyone experimented with a slightly thicker headgasket to avoid prem fuel? You will lose a little efficiency by giving up compression ratio but often just a half point of compression will allow for quite a few octane drop.

Originally Posted by skucera

Forgive me for coming to the discussion late, but my old 1989 Range Rover classic had the 4.0's thicker composite head gaskets, put on by some previous owner. I didn't know it, though. We ran premium gas in it regardless because it would ping slightly on regular gas. However, I didn't know it had composite head gaskets in it, so when it sprung a leak in one of the head gaskets, I bought the OEM stamped steel head gasket set and pulled the heads. The composite head gaskets are definitely thicker than the 3.9's stamped steel head gaskets, and after I had the motor back together it was much peppier, perhaps 10 hp worth! It also definitely required premium gas, and it pinged at all speeds on regular in my one experiment. It pinged so bad that I poured a bottle of "104 Octane" additive into the tank as a precaution, and filled up a few times after using only 1/4 of the tank to increase the octane. Once it had a tankful of premium it stopped pinging.

So, there's one data point.

Scott