Is the design of the 3.9/4.0/4.2/4.6 inherently bad?

[m3 bavaria]

Since I managed to melt my 4.6, I've been looking at options. Depending on who I talk to, it seems that the wet sleeved engine is prone to imminent failure. It's not a question of if, but when. It also seems that an engine with new head gaskets isn't a benefit as it's an indicator of failure and will only repeat said failure.

I'm considering buying a Disco as a temporary truck and dumping buckets of money into my Rangie. However, if a Rover engine is doomed from inception, perhaps that's unwise and I should be looking at something made by GM...

I'm also curious what I should steer clear of in my Disco search.

 

[proper4wd]

They are not inherently bad. Your engine failed because it was mistreated and the cat plugged causing the engine to overheat badly.

They CAN be prone to small cracks behind the liners but the top hat liner short blocks solve that problem.

Now, a all-aluminum Chevy 5.3 would be a great engine in a Range Rover... and it may be a worthwhile swap but don't expect it to be easy. To do it right will take hours upon hours of engineering, re-engineering, fabrication, and electrical work.

 

[m3 bavaria]

Right. I'm hardly blaming the truck for my idiocy.

At the same time, I've been told that if you do the head gasket once, you'll do it again. It also seems like MANY trucks advertise new head gaskets. Were they all abused too?

 

[proper4wd]

Lots of times the head gaskets leak oil and are replaced. It is not necessarily indicative of a greater engine problem.

 

[ZG]

I firmly believe it was a poor design. A lot has changed in technology in 50 years since the Buick V8 was introduced.

 

[Howski]

A major flaw I am aware of is the fragile and insufficient cooling system. It makes these trucks very easy to overheat which leads to many of the headgasket issues

 

[m3 bavaria]

So if the head gaskets have been replaced, is this a positive or negative selling point?

 

[ZG]

POSITIVE!(If done correctly) If I bought another Disco it'd only be one that's already had them done.

 

[m3 bavaria]

How's your truck holding up Zack? I'm looking for an 02-04 just like yours if I can't find a clean D1.

 

[proper4wd]

There is nothing wrong with the engine design. Of course there have been substantial advances in engine technology since the engine was originally designed, but that is irrelevant.

There are literally countless Rover V8s around the world that have powered these vehicles, reliably, to great success.

Some issues arose late in the engine's application that are the result of several factors. They were pushed to their limit emissions-wise. Tuned as lean as possible and cooling systems as hot as possible. No margin for error. I have also heard that tooling quality degraded over time although this is unsubstantiated.

Contrary to other opinions I would much rather buy an original truck that had not had the head gaskets done. This way I would know the true condition of the engine and if the work needed to be done I could ensure the quality of the work. Replacing head gaskets, while truly a straightforward job, is not something that the average backyard mechanic or gas station garage can do well enough to give me peace of mind.

 

[ZG]

How's your truck holding up Zack? I'm looking for an 02-04 just like yours if I can't find a clean D1.

After lots of work, it's holding up great. Personally I'm happy I went with the 02, seems like the 4.0s have less issues with liners than the 4.6s. I also upgraded the front grille/headlights and put in a locking center diff to get everything I wanted from an 04. I was actually looking for a D1 when I got this D2.

 

[LandyAndy]

If the 4.6 crank & rods are still serviceable, then why not build up a 'strong' 4.6 using a 4.0 block & pistons. Would be fairly cheap & as the 4.0 blocks suffer less from slipped liners you get the best of both worlds plus a small increase in BHP due to the reduced dish in the 4.0 pistons

Just make sure you get the block 'hot pressure tested' by someone who knows what their doing..... just my 2c

 

[m3 bavaria]

If the 4.6 crank & rods are still serviceable, then why not build up a 'strong' 4.6 using a 4.0 block & pistons. Would be fairly cheap & as the 4.0 blocks suffer less from slipped liners you get the best of both worlds plus a small increase in BHP due to the reduced dish in the 4.0 pistons

Just make sure you get the block 'hot pressure tested' by someone who knows what their doing..... just my 2c

Great idea, but I'm in a small town with a lack of garage options. I'm also far too busy and far too ignorant to wrench myself.

At this point, exotic isn't really a benefit for me unless it's something that really makes me happy (significant power).

 

[m3 bavaria]

There is nothing wrong with the engine design. Of course there have been substantial advances in engine technology since the engine was originally designed, but that is irrelevant.

There are literally countless Rover V8s around the world that have powered these vehicles, reliably, to great success.

Some issues arose late in the engine's application that are the result of several factors. They were pushed to their limit emissions-wise. Tuned as lean as possible and cooling systems as hot as possible. No margin for error. I have also heard that tooling quality degraded over time although this is unsubstantiated.

Contrary to other opinions I would much rather buy an original truck that had not had the head gaskets done. This way I would know the true condition of the engine and if the work needed to be done I could ensure the quality of the work. Replacing head gaskets, while truly a straightforward job, is not something that the average backyard mechanic or gas station garage can do well enough to give me peace of mind.

This is in line with what I was thinking. I'd rather know than not know. Plus, if it's original, I can gauge the level of care.

What's with this sleeve non-sense my mechanic mentions. Granted, he's hugely biased towards Toyota's, but he makes it seem like the engines are time bombs. Still, I see so many beat to death abroad that seem to run forever.

Too bad you aren't really transient. I have a Bimmer up in Hanover that I'm about to ship to Texas. You could drive it down, work on my Rover, and fly back all for a tidy fee!

 

[LandyAndy]

What's with this sleeve non-sense my mechanic mentions. Granted, he's hugely biased towards Toyota's, but he makes it seem like the engines are time bombs.

The casting thickness behind the cast in steel sleeves on some blocks is porous allowing cooling water to get into the combustion chamber & pressurise the crankcase system. The liners can also work loose & slip down, the fix for this is to have the old sleeves machined out & shrink fit a set of new steel liners that have a 'top hat' lip on them, they then seal fully at the top & can also, never slip down into the engine.

BTW, building up a block isn't that hard, just a bit time consuming and needs care.

Here's my 4.0 block after pressure testing & hot cleaning.....

And the view from below with the 4.6 crank & rods back in it....