Are diesel engines worth the extra cost?

[hobiecat]

I read this post from someone on the internet which interested me. Do others agree?

The key reason the diesels of old got their fabulous reputations for reliability involved mostly getting a handful of power out of several tons of engine. I am personally convinced that if there were gasoline engines that weighed two tons and made a mere 160 hp folks would expect and get fabulous lifetimes from them as well. The kicker here is that modern diesel engines are finally getting the flab trimmed off and producing power per pound similar to today's gasoline engines, and the sad (but poorly understood) truth is that they will have lifetimes more like their gasoline brothers. That said, nobody today specifies old fashioned engines in new/modern boats.

 

[rich]

But they last a life time, when speed did not matter /forums/images/graemlins/wink.gif

 

[Nautical]

Nordhavn !

well on reflection they are modern engines but designed/built to last thousands of hours.

Had a an ex Solent class life boat once with twin Gardner 6LXB's, now they were a real man's engine, problem is to build them new today would cost a small fortune, they might last 50 years but they would be as expensive as the boat.

 

[hlb]

There's no contest between diesel and petrol, for a thousand reasons. All said on here many times before. Ever heard of a petrol Juggernaut???

 

[ccscott49]

Well....................now you mention it yes, lots of petrol juggernauts, but mainly in the USA, but we had antar tank transporters in the army which had V8 petrol engines and the scammel trucks and recovery vehicles were in the main petrol, but you're right of course not as many nowadays.

 

[Nautical]

Lots of military stuff used to be petrol, had a Stally once with a straight six Rolls Royce petrol engine, about 6 mpg /forums/images/graemlins/shocked.gif

What ever happened to those petrol / paraffin engines, my dad had one in a converted lifeboat, used to start it on petrol and once it was hot enough you turned it over the paraffin. Is paraffin subject to fuel duty / tax as red is?

 

[ccscott49]

If you are talking stally as in Alvis Stalwart, it had a B81, eight cylinder rolls engine.

The six cylinder B60 was reserved for Humber 1 ton truck, "Pig" and it's derivitives and the ferret scout car, also used in a fair amount of RE plant.

Petrol/paraffin (TVO) went out years ago, too got expensive and diesel replaced them. Great engines though.

 

[hlb]

Dunno. It used to be called ESSO Blue.

You can run your car/ truck/ boat. Off kerosene, with a little hydralic oil added. Not sure how much.

 

[Nautical]

Your right, twas an eight cyclinder jobbie, was quite a while ago when they were first released, great fun but they had stripped out the impellers from the jet drive so no water sports unfortunately /forums/images/graemlins/frown.gif

here it is / was

 

[ccscott49]

Very late stally that, with hiab, large engine covers, designed by me, to stop the fires caused by split petrol cans dripping on the red hot exhausts!
Pity about the disconnected jets! They were great swimmers! You could have used landrover propshafts to re-connect them, we used to!

Yeah dont mess with cordite with anything, burns fast doesnt it!

Would still love to get hold of a stally, drop a high speed diesel in it and full swimming gear, loved those trucks! Did have a problem if used on the road too much with wind up in the reduction boxes, due to tyre size, destroying tracta joints.

 

[hlb]

The key reason is, mostly you can not buy petrol at sea. Reason is. no one wants it. They all have diesels.

Added to that. Diesels now adays are quiete, also good on performance.

For tootling around you bay, petrol may be ok. But for extended trips, diesel is the only way to go. You simply cant buy oetrol.

 

[ccscott49]

Haydn is correct of course, safer, cheaper to run in fuel and nowadays easy to start, powerful, quiet, light and ultra reliable. Plus of course you can get diesel anywhere near the sea, petrol no, mainly have to bring it with you from the local garage.

 

[Alrob]

I find it strange that you guys cant get petrol, up here on the clyde I can get it at Largs & Dunoon - not sure about Troon.
I wonder if things will change next year as we maybe see petrol power more in use - who knows !!!

 

[Nautical]

The guy I bought it from who was ex military said the same and best thing to do was every so often (when no one around of course) was bounce it off a big kerb or summat and get the wheels in the air. I imagine to stop axle wind up, used to do it every now and then or take it off road and bounce it about a bit and didn't have any probems.

Hiab was great bit of kit but with no stablisiers you didnt want too brutal with it or you would end up on your roof /forums/images/graemlins/grin.gif

Yes cordite,tis not funny stuff, did a demo thing with the TA, mock landing on beach and pyro co that supplied the artilary and ground motar dummies cocked up and we stuffed the wrong one up the breach, flick switch and boom! blew back of casing to bits and almost me too /forums/images/graemlins/frown.gif

 

[Deleted User YDKXO]

Yup, all been said before on this forum. For the record, diesel engines are inherently more economical, praps 20-30% more efficient than petrol engines, diesel fuel is safer, petrol is less available in some areas and diesel engines have more low down torque than petrol engines so are better for accelerating heavy lumps of motor boat
I do tend to agree with you that the current generation of high revving small capacity turbocharged/supercharged/aftercooled engines are far more stressed than the older low revving large capacity normally aspirated engines of yore and may well have a much shorter life

 

[Renegade_Master]

Also Mike I have found recently that a lot of petrol engined boats in our Marina that have......shall we say not been used much...............have ended up needing new manifolds as they have rotted through.

They do seem more vunerable to neglect when in boats than diesels.
do

 

[hobiecat]

if modern diesel and petrol engines have a similiar life and fuel prices become similiar - is it really worth paying all that extra to buy a diesel engine anymore?

 

[Deleted User YDKXO]

Yes for the reasons I've already stated. In any case, in most markets, marine diesel is already the same price as petrol. In the Med, for example, you see about the same ratio of diesel to petrol powered boats as the UK. Diesel has more than enough advantages to compete on level price terms with petrol

 

[Ifraser]

I'm just about to fit two of the aforementioned high revving small capacity diesels to my boat... mercruiser 1.7 d's.. yes the ones that should have been fitted in april!! I'm hoping to get to retirment (13 years) with them and then have a bit of residual value to buy my dream boat... am I hoping for too much... watch this space.. Hopefully I'll let you know in 13 years.. cheers Iain

 

[ccscott49]

In the meddy diesel is a lot cheaper than petrol. But doesnt really change your point.
Most of the petrol powered boats are the same as UK, small.