Thoughts on Transplants- 300Tdi vs. 3.9 v8

[Dendy Jarrett]

OK, So, I get the drive by wire theory and the simplicity of diesel verses petrol engine, ... but, I know currently of 4 of my rover buds that have done transplants of 300 Tdi's in Discos or Defenders that are having nothing but trouble with them.

One of my buddies got a raw deal - has had his rover in two shops for over a year and is pushing "stupid" money on getting his 300 Tdi transplant sussed out.

I am just wondering why?

Is it really worth it? I have friends who have "good" V8's that have given them many years of trouble free service.

With the price of diesel these days verses gas. When does the investment make sense?

I ask because I have (and still do) contemplate this idea, ... but cannot really see where it makes sense to yank a nice V8. Possibly could see it make sense if an engine install became necessary.

I'd love to get feedback from folks.

Thanks
Dendy

 

[lwg]

Here's my two cents. A diesel conversion will never be worth it financially unless you keep the truck for something like 10 years. I only know of one 300TDI conversion that didn't seem to work out. Not sure if they just had a buggy engine or if it was overheated in a previous life or what, compared to literally dozens of successful conversions and happy owners. I myself and seriously thinking about doing a TD5 swap in my D2. I ran the numbers and it will take me about 5+ years to recoupe the costs from purely a fuel mileage standpoint. However after the initial capital investment into the powerplant I will have effectively doubled my fuel mileage and cut in half my fuel costs for those 500 mile weekender trips. To me this is much easier on the pocketbook when it comes to planning out a roadtrip financially.

In the end the decision to do the conversion is a very personal one and will depend on your particular situation.

 

[Rocket Ship]

To properly have this discussion, I think we need more details on what is wrong with your friends' 300's. What is wrong with them, and where did they get them? Only then can we discuss how this should be done properly, and it's relative merits.

The 300 has a reputation for being a reliable and efficient engine in worldwide use, in both civilian and military applications. The V8, does not have that reputation. The 300 is installed by the OEM in these vehicles and swapping one using predominantly factory parts is straight forward. If good quality factory parts are used, you can expect factory reliability. If this isn't the case, then something has gone wrong with the installation, and it is not the fault of the 300 itself.

The fact that diesel fuel is significantly more expensive than gasoline is an anomoly almost unique to the US. The same is not true in other parts of the world. The case for diesel makes more sense if you are driving outside of the US.

http://www.see-search.com/business/fuelandpetrolpriceseurope.htm

It's also not a question simply of cost/mile. Depending on what you're doing with the truck the far greater range of a diesel conversion may be the desired result.

 

[LtFuzz]

My 6.2 gets about 420-450 miles to a tank. With four jerrycans I could touch 900 miles without seeing a fuel pump. Is that necessary in the U.S.? Probably not. But it's definitely in the "Pro" column where as the built DI/DII, with roughly half the range, sits firmly in the "Con".

Diesel and premium fuel (i.e. what the Rover V8 "requires") are usually within a few cents of each other -- and if you were a serious home-brewer there are quite a few cost-saving blends you could easily manufacture, and quite a few that require very little processing at all -- Eric (REDROVER) recently changed the oil on his RRC 6.2 and then dumped that oil into his gas tank. I couldn't help but think of Waterworld, where Kevin Costner purifies and then drinks his own pee.

The cost of the 300TDI motor itself, not counting the conversion, is prohibitive to me and makes it difficult to justify beyond it being a very cool and "correct" conversion; while perhaps not intrinsic to the vehicle I think there is quite a bit of value in that alone, especially for 4x4 people (and even moreso for Rover people).

If you post a for sale ad on any 4x4 site and your title includes "Model X w/Diesel Conversion" you're going to get at least double the views, in my experience. There is just a great overall level of interest in 4x4 diesels that aren't pickups. Some of that is the mythology surrounding diesels, I think: by and large the consensus -- even zeitgeist -- in the 4x4 community is that a diesel is much easier to maintain and much less likely to fail. Certainly not true in every case (witness the VW TDi cam failures that have been grenading $40k Jettas and Passats for the last few years) but certainly longevity and economy are two inherent characteristics of a diesel.

And if you're considering a long distance trip into truly remote areas the investment could be considered mandatory. That will never be an issue for 99% of us -- but isn't part of Land Rover ownership having that feeling that you could?

 

[lwg]

And if you're considering a long distance trip into truly remote areas the investment could be considered mandatory. That will never be an issue for 99% of us -- but isn't part of Land Rover ownership having that feeling that you could?

Truer words have never been spoken!

 

[Rocket Ship]

My 6.2 gets about 420-450 miles to a tank. With four jerrycans I could touch 900 miles without seeing a fuel pump. Is that necessary in the U.S.? Probably not. But it's definitely in the "Pro" column where as the built DI/DII, with roughly half the range, sits firmly in the "Con".

But there's a counterpoint to this. Sometimes having a diesel engine *requires* you to have longer range. Sometimes it can be hard to find diesel. Up here, in the middle of nowhere, you can often buy gas from outfitters, airports and snowmobile rest stops. But they don't have diesel. With a 900 mile range it's not likely to be something to worry about, unless you really didn't plan your trip well. But it's worth mentioning.

And if you're considering a long distance trip into truly remote areas the investment could be considered mandatory. That will never be an issue for 99% of us -- but isn't part of Land Rover ownership having that feeling that you could?

+2

 

[DividingCreek]

A year in the shop throwing stupid money @ something sounds very suspect. I have a customer truck here that in my spare time I have been working on for a year but I'm also financing a lot of the parts being bolted to the truck, I'm also not a shop. This is a reverse- diesel to v8 conversion, and the scope of the project has changed several times. The tdi's are incredibly simple engines. Over on the d90 board a guy on a trip from San Diego to Alaska overheated, blew his head gasket, and dissasembled the engine, had the head shaved, and put it back together in a friends drive way in a day and a half having never done the job before. It took them 2.5 hrs to have the engine in half.

 

[Snagger]

It makes sense to do the swap if you have a problem with the existing engine and it needs to be extensively overhauled or replaced, but otherwise is probably not worth the effort and expense. The 300Tdi is a good engine (I have one in my RRC), but is not as smooth or powerful as the V8. It has its advantages of the 200Tdi (I have one of those in my 109), but has its weaknesses too, notably its thinner head and issues with head gaskets and P gaskets. While it's much more refined than a 200Tdi, it's not as tough. performance is similar and both are markedly lower than what you're currently used to. Both will give about 30-35mpg in a clean Discovery if driven frugally and both are pretty reliable. The big advantage compared to a V8 is their indifference to water - as long as it doesn't go down the intake in large quantities, then the engine doesn't even notice water splashing around, unlike the V8 which is extremely allergic to water.

 

[dcwhybrew]

A year ago, I evaluated whether to convert the engine in my 91 RR to a 300TDi. I decided against it. No matter how you tweak the facts, the costs of the conversion vs the improved fuel economy doesnt pay for itself. As mentioned above, diesel isnt available in many remote locations in the US - gas is. It's not the Rover V8 that is the problem, its all the crap that is bolted on to it. The Rover v8 and drive line are very reliable (until you start exceeding their capabilities - which is true with any drive train).

When I was thinking about my conversion, I spoke to my former LR Master mechanic in Las Vegas, NV, Bill Goodman. Bill is from the UK and has driven plenty of 200 and 300 TDis. He agreed with the simplicity, but said they're old, they're slow, they're hard to find parts for in the us (probably easier now thanks to RN and DAP). Bill's honest suggestions were;

1) stick with the Rover V8 and upgrade to a 4.6 if a new engine was necessary.
2) if I really really wanted to do a conversion, go with the chevy 350 (LS1???) conversion. That engine has proven reliable. Yes there are failure stories with the sbc 350, but the % compared of the number produced is extremly low. Plus with the Chevy, you get the increased horsepower, better reliability, parts availability, and similar (if not better) fuel economy on regular unleaded gas (.20 cents cheaper per gallon than premium).

It seems to me that the diesel conversions are purely do to the uniqueness and romance of having a diesel. Yes, they seem to go on for ever (mileage longevity) but so too are gasoline engines. And if you do the conversion, you'd probably be hard pressed to find a mechanic who hasn't worked on a 350 v8. Especially out in the boonies.

LOL, so I took the option not mentioned and sold my 91 RR along with my POS 06 F350 PSD, and subsequently my 99 E320 and bought a LR3. Should have kept the 91 RR and 99 E320. Oh well.

 

[dcarr1971]

I've day dreamed about doing diesel conversion on my D2 ever since getting it over a year ago. Pretty early on I concluded given the expense and the current emissions regulations in my state (PA) there was no way a conversion would ever be practical. I've concluded that by the time I would put away the $$$ to do it correctly, I'll be able to just import a Defender 110 with a 200 TDI...

 

[Rocket Ship]

It's not the Rover V8 that is the problem, its all the crap that is bolted on to it.

I completley disagree. The Rover V8 engine is a terrible design. GM abandoned it in the 60's, Rover thought they could fix the casting problems, but obviously they didn't. The only reliable bits are the new Bosch electronics bolted onto the Thor engine. The fuel efficiency is crap, and it requires premium fuel to boot. It was no joke that it was mentioned in Cars 2.

 

[I Leak Oil]

Only reason to do a diesel swap here in North America is for the cool factor. And yes, they are cool. Otherwise, gas is far easier to find and the range thing can be overcome in other ways (bigger tank, carry less crapola, more gas cans, don't be lazy and just stop more often). With that said, I can't wait to swap my gasser for the 2.5L diesel I'm working on! I love the sound of tractor engines!:elkgrin:

 

[DividingCreek]

I have a 96 D1 with 86k and the block has a scored cylinder. My dilema is I can probably buy and import the stuff to convert it to tdi for about the same as a decent "known" used 4.6

 

[LtFuzz]

Otherwise, gas is far easier to find and the range thing can be overcome in other ways (bigger tank, carry less crapola, more gas cans, don't be lazy and just stop more often).

You're not overcoming the Rover V8s fuel consumption. You're carrying more gas at the expense of other stuff you might enjoy or even need.

 

[Rovertrader]

As you know I have had several Tdis w/o issue. My suggestion to success is to drive the donor first, period. This has not failed me yet. The payback in fuel is there, but takes time, aka miles- 30mpg vs 12mpg, so almost 3x the range immediately. I am not a fan of the lower power, but am a bit impatient. A 130 pulling a trailer up the mtn in 3rd gear about puts me over the edge. Conversely, sailing across the States in 110 Tdi at 75mph getting 28mpg is a hoot for sure. Cool factor, undeniable- but why? Only because we don't have them here. Me personally, the SBC is the answer- power, economy, reliability, parts availability. The only negative, is the resale. Whilst a great option, not pure Rover heritage, and thus poor resale. My 130 project has a new SBC and I have a nice 200 looking for a home and tempted to utilize it, but a 130 with 300 hp, and return 18 to 20 mpg is hard to beat... We all want what we don't/can't have, and as such, there are associated issues- parts, poor engines from who knows where, etc. I still love the pic of Doug's 130 Tdi running with a hole in the block- that is solid!!!