Petrol?

[Rick W]

Any recommendations on what I should do , if anything, about using additives etc for the go-go juice for my little Morris. Bearing in mind its a '44 truck. Someone did say I shouldnt need to use any additives as war gas was so poor. :?

[TooTallMike]

Our petrol engine guru told me that there was no lead in petrol in the 40s. On the strength of this I've always run my (US) wartime vehicles on unleaded without any apparent problems. Many people use additives.

 

Far more of a problem is the octane rating. The Austin 10 drivers' club recommend the use of 10% diesel added to unleaded for 30s & 40s cars. This is enough to drop the rating but not enough to cause smoke.

[Rick W]

Thanks Mike, I heard similar regarding the octane rating.

[Degsy]

Ther are several good reasons for not using diesel, even as little as 10% will increase the compression ratio, not good on an old engine and the diesel has to go somewhere as it will no burn, if there is war in the bores it is liable to build up in the sump oil with possibkl]ly catastrohic results. It is much safer to use an additive, I have used pellets which are droppred in the tank and are good for 250,000 miles use, the guarantee states that if any damage results from their use the supplier will pay for a newengine plus fitting costs.

[TooTallMike]

Good point about the worn bores in older vehicles causing diesel leakage into the sump. (Of course in a good engine it just goes out of the exhaust.) I didn't know about it increasing compression ratio and that would indeed be a concern for older head gaskets etc.

 

As for pellets, are you talking about lead pellets which are left to dissolve in the fuel? I've read some bad stuff about these. It mainly relates to their being no control over the lead/fuel ratio. (Apologies if this is not the type of pellet you are referring to.)

 

The Federation of British Historic Vehicle Clubs (FBHVC) carried out extensive tests on additives and recommends a number of them. (a list can be found at http://www.fbhvc.co.uk/fuel/additives.htm) They are equally recommended and should be chosen based on local availability.

 

[Degsy]

No, not lead pellets, these are a product which goes back to when Hurricanes were being supplied to Russia and something was needed to use with the poor quality fuel that was all Russia had at that time, of course the product has evolved since then.

[Mark]

I use normal petrol in my jeep as the mileage is low compared to a modern car, because it is low then none or minimal damage will occur because of this, and this is from the guy that makes and builds engines for a living.

[Karoshi]

But Mark, thats confusing to some of our readers, a M38 of '50 something manufacture............ is modern.

 

I mean its not like a proper jeep, with a proper engine.

[Mark]

But Mark, thats confusing to some of our readers, a M38 of '50 something manufacture............ is modern.

 

I mean its not like a proper jeep, with a proper engine.

 

 

Is it confusing to you, or are you saying that some of our readers are thick, having just had the engine stripped and the bores honed, rings replaced and gaskets changed, all the valves have been checked and are within correct tolerence according to the manual etc. minimal wear after all these years, the latter being run on unleaded petrol, and from the mouth of a man with many years of experience (like yourself of course) due to the low mileage that the jeep is doing per annum there is no requirement for any additives to be used, now I cannot say that for a "proper jeep" as you so put it maybe they were not built as well as PW ones, so the people on here will have to make up their own mind as people will do on a forum, but for me it's good.

[ashley]

Ask ten different people this question and you will find the camp divided usually 50-50, for myself i have had some good friends who have put unleaded fuel in their jeeps(wartime ones) and they have ended in disastrous results, requiring the unit to be replaced :cry: .

For myself i have gone down the use of additive route.

 

Ashley

[Marmite!!]

There's a bit of info on Doug Genville's DGA site..

 

http://www.users.zetnet.co.uk/lsm/dhmg/octane.html

[Richard Farrant]

Our petrol engine guru told me that there was no lead in petrol in the 40s. On the strength of this I've always run my (US) wartime vehicles on unleaded without any apparent problems. Many people use additives.

 

Mike,

 

I am afraid your guru is not correct.

In the British Army during WW2, leaded petrol was introduced in 1941, MT75 had a lead content of 1.2cc per gallon and it was for general AFV use excepting Carriers (ie Ford V8 engines). Some US tank engines could not run on this so MT87, another grade of leaded petrol was used.

 

In 1942, MT80, with a lead content of 3.6cc per gallon was substituted for the MT87 used in the US tanks. This gave the need to modify certain US tank engines in British service to lower the compression ratio.

 

1943 and MT80 was introduced for British engines (trucks and lorries, etc) and along with it, a host of defect reports with valves sticking and burning, corrosion, etc. It was found to be certain makes that suffered and mods. had to be done be made to exhaust valves (improved alloy steel) and guides. You may come across manuals for certain vehicles stating if MT80 is used, that valve clearances are adjust to a larger gap.

 

Interesting to note that the Rolls Royce Meteor in the Cromwell tank and the Bedford flat 12 in the Churchill, suffered none of these problems.

 

I think that lead had been introduced into the civilian petrol in the late 30's, namely Ethyl petrol.

 

Richard

[mcspool]

Dr. Ulrich von Pidoll's in his book "Kaefer: Ein Auto schreibt Geschichte" (Hamburg: Nikol, 1996, ISBN 3-930656-36-1) quotes a 1986 SAE technical paper. A number of SAE tests (incl. one on Army vehicles) proved that the wear on valve seats and valves with unleaded petrol is not noticeably higher (compared with leaded petrol) if the engine is operated under 3,000 rpm.

[Richard Farrant]

Dr. Ulrich von Pidoll's in his book "Kaefer: Ein Auto schreibt Geschichte" (Hamburg: Nikol, 1996, ISBN 3-930656-36-1) quotes a 1986 SAE technical paper. A number of SAE tests (incl. one on Army vehicles) proved that the wear on valve seats and valves with unleaded petrol is not noticeably higher (compared with leaded petrol) if the engine is operated under 3,000 rpm.

 

 

Hanno,

 

You have to go back to the war years and find out that the introduction of lead caused untold engine failures, although some makes and types of engine were more susceptible than others. The problems came about when lead build ups on exhaust valve stems caused valves to stick or not reseat firm enough, subsequently burning valves and seats. The introduction of harder alloy steel valves and seats got over the problem as well as modifying the guides. Admitted more up to date information as you quote, shows that the wear on seats with unleaded is no higher than with lead added, it was quite the reverse when the British Army used it in 1943/44.

 

This information came from a War Office report.

 

Richard

[john wheatley (R.I.P.)]

I fitted an in-line converter which is plumbed in between where the two tank pipes to make a common feed and the carb. so I can use unleaded fuel and I use Redex as an additive and Bertha chugs along quite happily. :eek2:

MERRY CHRISTMAS to you all and all the best for 07. May all your engine problems be imaginary. :wave:

[Centurion]

I realise that all the comments relate mainly to 1940.s vehicles. So where does that put my Hotchkiss. The engine is a1940,s design but was probably built in the early 60,s and was rebuilt by the French army in 1984 :?. I run it on unleaded and put castrol octane booster/lead substitue in it and it runs fine, but am I wasting money on the additive.

 

On a similar thread unleaded petrol contains all sorts of unfriendly chemicals and if left in the carb for a long time it evaporates and leaves some of these behind which clog up the jets. . If I park my M/cycle up for a few weeks in the winter I always turn off the fuel and run it until the carbs are MT and it stops.

Best wishes for Christmas and the New year to all.

regards

Centurion