300tdi on the motorway

[Diff]

I have been running a 2.5 petrol with Turner stage 2 head and ACR cam for many years on lpg 100% of the time in my 1985 110 CSW. My nearest lpg station is taking out its pumps in 3 weeks. The only other lpg is 11 miles away and anything else is more than 20 miles away. The cashier in the Shell station says Shell are getting rid of lpg across the board by October!

Slightly concerned that if I drop a 300tdi engine in, I will be disappointed by the noise etc. Whenever I see other newer Defenders on the motorway, they always seem to be going slower than me. I keep to 70mph except for steep hills when I can only manage 60mph. Are 300tdi owners going slower because it is too loud or does the engine not like 70mph all day? 

If I run my current engine on petrol, it is going to get expensive (15mpg on lpg). I have a great fondness for the 2.5 petrol engine. Very smooth and very tractable off road.

Any observations?

Regards, Diff.

[Gazzar]

What's your annual mileage?

[Tanuki]

I wouldn't put a 300TDi in - it's a 30-year-old engine which is becoming problematic to support with 'first-line-quality' parts!

[I run a TD5 and parts availability for that is not exactly good either].

If you're going to the bother of re-engineing, I'd always go for something that is still in current-production, so your investment-effort is less-likely to become obsolete/unsupportable in a few years.

There's also the consideration that replacing a rev-happy petrol engine with a low-revving Diesel will probably lead to you then going on to want a changed transfer-box-ratio to make it liveable-with...

If you must go Diesel, look at some of the this-millennium BMW lumps: they're torquey, revvable, quiet and efficient. Some Luddites will wail about "electronics" but personally I'm happy with engines I can 'tune' and 'diagnose' using a laptop to look at the errors rather than randomly swapping-in replacement parts in the hope it might fix an intermittent issue.

[pete3000]

My 110 300tdi i've always been happy with for last 14 years, i've got standard size wheels and a 1.410? transfer box. I stick to 65mph (on speedo) so most likely 60mph. Any more becomes a bit lively. It averages 22-25 mpg and is mechanically simple. I've kept my eye on the temp gauge and regularly serviced the fluid and cam belt.

I tow a sankey trailer at 55-60 and it has plenty of power and only ever considered a 3.9 v8 megasquirt if diesel is ever discontinued.

The td5 could be a consideration except the earliest versions. Other choices a 2.8 TGV or isuzu? I wouldn't want to stick a puma (transit engine) in though....

Pete

[Gazzar]

If the mileage is low enough then stick with petrol. It's likely to get cheaper in the next few years. Takes a lot of savings to pay for a conversion to a modern engine.

[Bowie69]

Yep, go with petrol, likely get closer to 20mpg to mitigate the price increase a little.

As above, what's your annual mileage?

[Will@LRW]

I sit at 65mph on the speedo. 70 is fine but a bit loud, and that is with a 1.2 transfer box. Also I prefer not to rag the nuts off it as it's an older engine (190k+) and I get better economy circa 33mpg; when i try to go around 70 it'll drop to 29mpg

[reb78]

My 200tdi is pretty happy on the motorway. I do have an overdrive though. The 110 will sit happily at 80 all day long. My mileage is ~25k a year in normal years that is, mostly in 300 mile chunks. I run it on veg oil in the warmer weather to keep costs lower too. Its not the quietest, but I have a nice loud radio and the overdrive helps quieten things(if you don't increase your speed with the extra gearing too much!)

[oneandtwo]

I ran my 300tdi 90 hardtop with 1.2 transfer box with late Q gears, continental cross contacts, TD5 soundproofing mats and an amount of silentcoat, it was fine on the motorways. Quieter than the completely standard 56plate 90CSW I had at the same time.
obviously the Puma I replaced the td5 with was far better than both
 

300tdi Top quality parts availability is fine.

[jason110]

If your annual mileage is low enough run with petrol engine. It’s a much quieter smoother lump. 
 

the saving in fuel consumption from a petrol to diesel engine will take a fair while to offset itself against the cost of the engine and conversion costs given that the expected fuel economy of a tdi is only say 8-10mpg better but considerably noisier also consider diesel is more expensive at the pump too. 
 

if you must go diesel, sound proof everything, otherwise the noise is near unbearable for a prolonged period of time without ear defenders. 

[Mo Murphy]

8 hours ago, jason110 said:

if you must go diesel, sound proof everything, otherwise the noise is near unbearable for a prolonged period of time without ear defenders. 

Pardon ? 🙂

[Snagger]

Remember, second hand engines are going to be tired and need a rebuild, so don’t think a £500 Tdi is going to be ready to fit and forget.  The cost of doing a quality conversion is worthwhile compared to doing on the cheap to make sure that reliability is maximised and running costs, maintenance problems and breakdowns minimised, but you need to take a look at what the costs of a decent conversion are versus the saving from the better fuel economy.  As mentioned above, you need to also factor in the cost of decent sound proofing, as the Tdi is harsh and considerably nosier than a petrol, even at lower speeds.  If you’re doing under 5000 miles a year, then I’d imagine it’d be very hard to justify the conversion unless your existing engine needs a rebuild anyway.

[Mo Murphy]

Sounds like you could save yourself a pile of work and live with the economy or lack thereof.

I do like the 4 pot petrol engines but they very much are all of the economy of a V8 with none of the performance ! 🤣

Mo

[jason110]

5 hours ago, Mo Murphy said:

Pardon ? 🙂

Exactly sir 

[Ed Poore]

I think a lot of it is down to how much it's used and how well serviced / looked after it is. I've personally found the Tdis like to be worked hard. What used to be a fairly regular trip for me doing the entire length of the M4 I'd usually find about Bristol the 110 would like to sit 5-10mph faster than earlier. Guess gearbox and diff oils finally got up to temperature. Mines quite happy chugging along at 70+, 85+ (indicated) gets a bit noisy but I do have a fair amount of sound + thermal insulation in it (but also rotten doors and some holes in the exhaust which I really must get around to sorting).

I got back last weekend from 1600 miles around the Highlands and have to say I think there were only a handful of vehicles that overtook me both on the way up and down from South Wales and also in the Highlands. Bear in mind that a Puma engined Defender in 6th gear is pretty much exactly the same ratio as an R380 with 1.2 transfer box, they've just got a much lower first gear. Mine is running a 1.2 box and 32" tyres. The current engine has been fiddled a bit so certainly feels a lot pokier than most standard tune Pumas I've been in.

Having said all that if you're not doing the mileage and don't need a rebuild and you're happy then stick with what you've got.

[Daan]

I'd say get a good 300, it will easily earn itself back. A 200 is easier to fit to your car though, so that might be a consideration as well. It is a shame LPG never took off here, as it makes a lot of sense to use it, rather than burn it off at the refinery. One other route to consider is to get Calor gas bottles delivered to your home, and swap out the tank when it is empty, and get them refilled. This is what users of Forklift trucks are doing; not sure of the legality of this is on the road, but worth considering.

[Diff]

Many thanks for all your input. Very interesting that some 300tdi owners don't like driving their Land Rovers on motorways at the speed limit and others do. Quite a variety of comments. Daan, yes, I could have 47kg bottles of propane delivered to home and buy a transfer pump, but it would become a bit of a faff. Plenty to think about. Thanks all.

Regards, Diff. 

[FridgeFreezer]

I'd either megasquirt the 2.5 or drop a V8 in for motorway peace & quiet.

[Retroanaconda]

I quite happily spend literally all day on the motorway in mine, and that’s a 200Tdi so slightly less refined than a 300Tdi would be. Cruises comfortably at 60-65mph on the standard gearing and returns 30+ mpg, but will sit at 70+ no bother just a bit loud and inefficient. I now have an overdrive and so tend to cruise around 70mph as it’s so much quieter, however that knocks a bit off the fuel economy.

Mine is fairly well soundproofed on the bulkhead, seatbox and rear tub. People generally comment on the general lack of noise inside compared to other Tdi-engined Land Rovers. More could be achieved if I rebuilt the doors and added deadening to the roof I am sure.

It’s all relative, I’m used to driving a Land Rover as I’ve driven little else for donkeys years. Mine is quiet compared to some other Land Rovers, but it’s noisy compared to a modern car. As others have said, if you’re not doing a lot of miles then a petrol engine is probably a wiser choice these days. 

[Geojake]

@Diff just as an experiment on a long motorway drive yesterday, going 70mph on the clock (so a touch faster as I have bigger wheels) in my 200tdi, I opened up my decimetre on my iPhone. 

My Landy is soundproofed on front floors, doors and bulkhead but not the roof yet and it was averaging around 83dB. So pretty loud! But like @Retroanaconda I am used to driving large noisy trucks and almost enjoy the noise! 🥴 

I’ve never driven a petrol Defender to compare but would be interested in a comparison value.