DIESEL AND GASOLINE

No, gasoline had problems too.
At ultra low temps the small amout of water in the fuel will precipitate out of the fuel, and clog up the filters
There was a case a few years ago with aircraft engines that shut down as the fuel filter clogged with ice as the temp was below -40c
British Airways Flight 38 - Wikipedia, the free encyclopedia

Gasoline has problems sooner than Avgas, so at -32 to -40 will start to have problems.
Russian winters will often go to -40 or below

Correct. For a really cold winter every fluid in the tank could freeze or clog up, as the Germans didnt have the ultra-cold weather lubricants.
The Russians would leave their tanks running in really cold weather, or else would start a fire under the engine to warm it up

 

There are other considerations to be put into focus here as well. Cetane (diesel) ratings weren't standardized until post WW2, and in America the octane ratings were reached by entirely different methods than they are today.

That is because until the fifties, from the late twenties on; civilian gasoline was rated at Premium, 77 octane; Regular, 70 octane; and Standard, or less-than-regular, 50 octane. But then one must also remember that until the fifties America used the Motor Octane Number (MON) for both civilian and military use, and then changed to the Research Octane Number (RON), which is entirely different.

The Research Octane Number (RON, or F1) simulates fuel performance under low severity engine operation. The Motor Octane Number (MON, or F2) simulates more severe operation that might be incurred at high speed or high load.

So one must keep that in mind when comparing octane numbers in the twentieth century. The differences between RON and MON can range from 0 to more than 15 octane numbers depending on temperature and other variables. But MON numbers will always be less than RON numbers for the exact same fuel blend. We must keep those differences of measurement standards in mind when talking about "octane/cetane" numbers, and/or av-gas of 100 Octane or above.

 

Most modern tractor trailer units have a small "toe" operated water dump on the system. One puts his foot under the tank, finds the "push button", and dumps the condensed water out of the diesel tank. Depending on how fast you are using your fuel up per day/week, that dump clean is different for every truck. If I sat for couple of days finding a load, or waiting to dump one off, I would touch that valve with my toe on each tank every morning. The water trap worked exceedingly well, and the "crud" that would fall out of there was astounding.

 

Psst... Actually "combustible" and "flammable" are synonyms.

 

Diesel needs to be warm and comressed to combust. As said, petrol is more readily combustible.

Diesels tend to have a higher compression ratio in order to aloow it to combust (amongst other things). Diesel engines tend to be much longer stroke (and, therefore, produce more torque) but the thermal requirements of diesel means that the engines need to be bigger and heavier than their petrol counterparts. Diesels used to be had to start on cold days. however, by and large, the drawback one had to put up with in a diesel engine have largely been addressed by modern technology.

For larger vehicles, diesel makes a good deal of sense but the technology in WW2 was such that petrol engines were still preferred by many. The size of diesel engines precluded their use is tank like the Covenanter where a low profile was required.

 

I thought the ISU series was fairly low profile and that the Soviets used diesel.

 

Soviet engines are not something I know much about. I was applying my knowledge(!) of diesel engines to tanks generally. If that is the case with the T34, I am more than happy to be corrected.

Do you have any more info on this engine? I can't seem to find much.

F

 

Originally Posted by JBark
My only answer as to why anyone would use gasoline is the example of our forces in the ETO during WWII.

Reply by freebird:
"Main reason was the lack of suitable diesel engines with enough power"

freebird-

Can you tell me why you think there were not enough suitable diesel engines for use in the Sherman. By my read we put a bunch in and "sold" them to the Soviets and the Marines used a bunch more. On top of that other engines were tested, approved but not used because of the desire for one all purpose fuel in the ET (all of this from Hunnicutt.) So, what is meant by your statement?

 

Not an area where I have a great deal of expertise either. Here are some links with info though.
CHAPTER XII: Tanks
T-34 - Wikipedia, the free encyclopedia

Looks like not all T-34s had diesels!
Iosif Stalin tank - Wikipedia, the free encyclopedia
seems to indicate that the JS series used the same engine as does
IS-3 / JS-3 (Josef Stalin) - Heavy Tank - History, Specs and Pictures - Military Tanks, Vehicles and Artillery

 

Don't forget that the British used the Sherman III in NWE as well.

 

Thanks!

 

Not as simple as it seems. There were diesels and they worked well.
On January 10, 1942 the Armored Force Board at Fort Knox put forth a plan for the future in which they endorsed using in-line diesels for all army vehicles. They also went on to recommend twin diesel installations for all tanks in the 20-30 ton range, and specifically noted that radial engine configurations using any fuel were not desired. (essentially, we hate the Wright radial and love the GM twin diesels in tanks.)
But in March 1942 the War Department decreed that the US Army would not support dual fuels and that gasoline alone was to be used. This crushed the AFB's long-range plan.
The AFB ran several comparative tests of tank engines and in all three major tests the diesel engine was preferred over the gas rivals. But due to the War Department's decree they could not be used. So that's why the diesels went overseas.
Only in September 1943 did the war department relent to some extent when they allowed a small quantity of Shermans to be built with the Cat radial diesel as the M4A6.

There were engines.
There were supporters of the diesel.
Logistics drove the bus in this instance.

 

Nope.
A log that you put in your fireplace is combustible, but it isn't flammable.

Flammable liquid - Wikipedia, the free encyclopedia

I was actually thinking about the early war tanks, 1939 - 1941.
The twin engine setup was an example of an expedient (but poor) solution to the problem of lack of suitable engines.
You are correct about the logistics being the main reason for US tanks.
Be careful when you write "our forces", an it could mean "our" (US) or "our" (Allies).

I think Marseille's post pretty much answers your question.
My only answer as to why anyone would use gasoline is the example of our forces in the ETO during WWII.

 

Be careful when you write "our forces", an it could mean "our" (US) or "our" (Allies).

Why? Didn't the Allies (Allies) do what we (US) told them to do?

I think Marseille's post pretty much answers your question.

This answer does not address the question at all. My question was why you thought there were not enough deisel engines with suitable power available and along the same line how you came to believe this was why we chose gasoline engines. Marseille's post seems to indicate that there was no shortage of suitable deisel engines.

 

I'll assume that you are being sarcastic, rather than antagonistic or asinine.
The answer is no.

You are mistaken, I never mentioned anything about the Sherman.

Ok, the original question was "Why was gasoline used instead of diesel", not why did the USA use gasoline instead of diesel.

You said "My only answer as to why anyone would use gasoline", whichonly addressed it from the US point of view. My answer addressed the other major reason. I should have said "One of the main reasons", not the main reason in my answer.

The UK (and some other countries) used aircraft engines, radial engines & sometimes two engines to power tanks, despite the fact that diesels are generally better in tanks.
The Matilda used twin Leyland diesels, however it was underpowered, as they were originally bus engines.
The Valentine used a 131 hp diesel, but this isn't powerful enough for the heavier cruiser tanks.
They tried a horizontal 12 in the "Covenantor" which gave more power but the rushed design had problems with the cooling system so was never used in the desert.

Another example is the Cavilier tank. (from wiki)

The British had a shortage of tank engines until 1943, which also resulted in them re-using some older Merlin blocks.

So that's why my answer to Tactical Tank's question about why was gasoline used rather than diesel would be - "One major reason was the lack of available diesel engines with enough power"

 

Too bad you didn't direct it at that question.

I appreciate the information on British tanks. Good stuff. If you haven't already could you visit my thread on armor libraries and leave the names of books you value. Don't feel you have to anser the questions but I am looking for the names of good titles on armor (budget in mind.) Thanks.

 

Care to explain?
Thankfully the Allied did not "do as the US told them" in '42, we may have ended up with a disaster.
At the time of Pearl Harbor, when the Commonwealth had some 40 or 50 deployable divisions and the US had about less than half a dozen, the direction of the war more closely followed British direction. By late '44 when the US forces outnumbered the Commonwealth, the US took a larger share of the planning & direction of the war.
To his credit, when he was heading SHAEF Ike tried to be inclusive of the various Alled nations, rather than a "My way or the highway" approach.

Um, no.
I wasn't wanting to get into a great semantic debate here, but your reply didn't mention Lend-Lease at all, you said "tanks given to the Soviets", which most certainly wasn't limited to Shermans. The Soviets were "given" a large number of tanks from British & Commonwealth, they got some 3,800 Valentines and some 4,100 Shermans so it isn't a given that you are talking about Shermans. (and they got 1,000's of other tanks)

That was the part that I was expanding on, your reply gives the impression that a US decision to go with one a single fuel was the only reason, which wasn't the case with non-US production.

Actually no. As mentioned earlier, Tactical tank's question was about "why gasoline instead of diesel". The British may well have wanted to use diesel, but didn't because they had a shortage of engine production.

In any event, no use sniping about it, I think we've established that there are different reasons for the UK & US to use gasoline rather than diesel

Most of my collection tends to be of the strategic type, Brooke, Eisenhower, DeGaulle, Zhukov etc, not many armour specific books. I've borrowed lots of armour books from the library & Uni in my poorer days, but I'll be interested to see other's lists on the subject.

 

freebird-

Our conversation started here:
My only answer as to why anyone would use gasoline is the example of our forces in the ETO during WWII. Our people wanted one fuel only; one for all vehicles. Our tanks were built with diesel engines and we gave some to the Soviets to use and some were used in the PTO. I don't know what advantages one has with gas other than that...maybe cold weather starting?

I am clearly offering an example as to why one particular fighting force in WWII chose to use only gasoline in the ETO. This fighting force also fought in the PTO and delivered tanks to the USSR. By your evidence this is the USA. So, I offered one example for chosing gasoline over diesel and you replied with your statement about availability of adequately powered engines. I did not remember learning of this in my readings about the American armor engines so I inquired. I don't see how the rest applies.