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

[stolenheron]

Ticking could have been a slipping liner if it was that loud.

it probably was. we had a small ticking coming from the motor before we did the head gaskets at 55k, we had the valves reworked and replaced the lifters, ticking went away for a while. but when this ticking started it was 10x louder than any of the other taps/ticks i had heard in the past. you could hear it with the windows up and music/ac on inside the cab. you could also hear it when i pulled up at my apartment, from inside my apartment...

i traded the D2 in at a dealership, they will probably diagnose it and then throw it up at an auction for someone else to handle.

 

[Ray_G]

reliability is part of maintenance.

There you have it. Without a doubt the Rover V8 is an obsolete engine well past its prime, but it has served well and much of the stigma ties back to poorly maintained vehicles and specific issues with the D2s in particular. Note that you don't have the like amount of noise with 3.5, 3.9 & 4.2 engines nor not quite as much with the 4.0 GEMs. I'm not saying they are the best part of a Rover by any stretch, but having gone through several trucks (and several more engines within those trucks) I do look at it as part of doing business.

Something that would make many shudder but is illustrative; I've never had a Rover on a rollback other than when the clutch was grenaded-I cannot say that for my Toyota Tacoma(s). This includes being in the middle of a PCS move when the 4.6 in my D1 took decided it was truly done but I was halfway to Camp Lejeune in the middle of the night. Judgment call was to press on as I knew the upcoming deployment would provide the resources to fix/replace what was wrong; essentially the truck took itself and a trailer the rest of the way on 6 cylinders.

As someone said before, the engines are tough enough-sometimes past the point of sacrifice.

Add onto that the reality that the RRC/D1/Defenders are fairly easy to work on, have fairly limited electronics (particularly the 14 CUX but I don't stress much on the GEMS truth be told) and to me reliability becomes a facet of how well the vehicle is maintained and how well you can repair the things that must be fixed to move on.

It's easy to lose sight of that because the internet is over-populated with stories of people with problems (that's why they are on the internet) and then more people recycling those issues.

Personally the D1 with a 4.6 (built on a 4.0 block) is about the perfect in my book, though I did love my V6 Tacoma crew cab.
r-
Ray

 

[Holland]

I will have an extra m60b30 on hand in a few weeks...

Power of an M50 with the fuel economy of an M60. A M60b40 would be a cool swap though.

I know a bloke with an M52 swapped RRC. I hear that South African spec Defenders came with them for a short time.

 

[brushogger]

I absolutely agree with everything you said before this. The 2003 dowel pin drilling fiasco coupled with the numerous 4.0 and 4.6es I've seen with multiple loose liners (literally able to pull them out by hand when torn down to the block and the block heated to near operating temp) is all the substance I need to firmly believe their tolerances were little more than luck after the early 2000s or so.

Also, the bulk of the liner issues have been proven to be worked around with top hat liners. Which should have been installed from the factory.

THIS!!!!! These motors ( at least the 03's and04's) don't have to be abused, neglected, mistreated, or not maintained correctly to have catastrophic failures. I know this from personal experience. I didn't believe this either until making the mistake of buying one and having to eat $5k of loss 2 years later. Until someone engineers a good swap to a dependable engine steer clear. A rebuild done correctly with the top hats will run you at least $5k, and you still have an engine that requires premium, makes mediocre power, and has poor fuel economy.


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[reece146]

Power of an M50 with the fuel economy of an M60. A M60b40 would be a cool swap though.

I know a bloke with an M52 swapped RRC. I hear that South African spec Defenders came with them for a short time.

Hmm, non-VANOS M62B44?

Would this bolt to a D2 transmission? Replaceable bell?

 

[gm13]

I just met the owner of NAS Defender 90 #570 ('93, 3.9L) 275,xxx miles with no head gasket replacements or major engine work required. He told me a friend of his has a NAS 110 with 300,xxx, he wasn't sure about HG on that though.

 

[evilfij]

The 14CUX trucks are the best. There is a considerable about of debate whether it is the block (ie 3.5/3.9/4.2 v 4.0/4.6) or the engine management system which is the root of evil.

GEMS trucks were horrible about fouling the exhaust valves. Bosch trucks run hot and drop liners.

Both GEMS and Bosch trucks can suffer from dropped liners, leaky head gaskets, overheating etc.

My personal theory is that Bosch trucks were designed to run hot and lean for emissions reasons which causes the issues.

Anyway, I will never own a Bosch truck and have avoided GEMS trucks as much as possible. Me, my 4.2 has 193k with one set of HG because my GF drove it after the top hose blew. My D90 has 133k with the original HG. Other than new O2 and TPS and a cap rotor wires ignition module tune up type stuff, they seem fine. If they go, I have a new 4.6 block ready to drop in and two spare 3.9 motors.

 

[MattScott]

Is the design of the Apple II bad? No. But you wouldn't want to compare it to something 40 years newer, would you?

Same could be said for the Rover V8.

 

[evilfij]

Mattscott,

I think the correct analogy would be "you wouldn't want to try to surf the Internet on an Apple II."

In a lot of ways, that is what the rover V8 in 4.6 Bosch SAI trim was doing.

Early motors are basically fine.

 

[getlost4x4]

You guys smoke a lot of crack.

I have a bosch with 127k miles. I drive the crap out of it. I bounce it off 5500 rpm all the time. I bounce it off the Rev limiter occasionally when I'm trying to get through mud and snow.

There is a reason the head gaskets blow. You are using the wrong coolant and you don't maintain the cooling system.

If you can't take care of it get rid of it. If you can't afford it get a jeep. I've put over 50k mile on mine in 3 years and it's never left me stranded. And it's a P38.

I even use it in the oil field. I beat the crap out of it and it doesn't care.

But then again I use good oil, coolant and filters. Hmmmm crazy stuff.

Americans shouldn't own European cars. They don't have enough sense to maintain them.

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[Daryl]

You guys smoke a lot of crack.

I have a bosch with 127k miles. I drive the crap out of it. I bounce it off 5500 rpm all the time. I bounce it off the Rev limiter occasionally when I'm trying to get through mud and snow.

There is a reason the head gaskets blow. You are using the wrong coolant and you don't maintain the cooling system.

Yeah...the plural of anecdote is not data, and dexcool is not what kills these motors. I will agree that dex tends to turn acidic faster when there is air in the cooling system, and the D2/P38 cooling system is problematic to bleed so this is more of a factor......but it's not the problem.

That's great that yours runs well. But like I said before, tolerances were little better than luck at some point as the tooling was obviously worn out and not being maintained towards the end of the line of these motors.

Americans shouldn't own European cars. They don't have enough sense to maintain them.

OK....I'm not even sure why I responded to you with any sort of though when you are just trying to be inflammatory...but whatever.

My personal theory is that Bosch trucks were designed to run hot and lean for emissions reasons which causes the issues.

That's not just your theory, it's a fact. They were run hot for emissions and to juice the last bit of performance they could get out of them (on the cheap) the attempt to be competitive with modern offerings. There is no excuse for the different between "normal operating temperature" and "oh ****, I just melted a piston" to be as close together as they are on the Bosch motors other than a massive compromise for something that should have been replaced long ago.

 

[Fivespddisco]

Getlost has a P38 and for some reason they cool better. He may also have Gems block and they were the longer lasting IMOP

 

[stolenheron]

really? I switched away from that dexcool crap the moment my dealership warranty ran up. synthetic oil since the day i purchased the car and quality filters used every time.

genuine parts for every replacement under the hood. etc etc.

I did absolutely everything right with caring for and maintaining my 4.6L bosch SAI motor and it still had many problems including 1 set of HG.

cooling system was well maintained, never overheated. t-stat was replaced once. radiator cracked (plastic broke and caused a small leak) and was replaced with genuine parts radiator. coolant levels, as well as oil levels, were checked at least every 2 weeks at COLD to ensure proper levels were maintained and in order to monitor the occurrence of any leaks.

the amount of money dumped into the truck was quite a bit, i could have purchased my rover 2x over easily. I still hung in there and kept on going through the bills. it wasnt until 6 years of driving it that i decided to step away, most likely away from a slipped liner as well....

 

[draaronr]

Who is a good 4.6 builder?

 

[David Harris]

Who is a good 4.6 builder?

D&D Fabrications. Mark there knows more than just about anyone in the US about these engines and does full service machining and parts on them.