Typical 1940’s racing fuel components

The following technical information is dated 16^th May 1946 and is provided in Jimmie Simpson's  little black book.

Components	Specific gravity @ 60°F	Boiling Range	Chemically correct mixture air /fuel by weight	Latent Heat, B.Th.U.S/Lb	Latent heat per pound of air in a chemically correct mixture (see note 2) B.Th.U.S	Lower calorific value B.Th.U.S/Gall
Petrol (aviation) base stock	0.720	50-150°C (50% below 100°C)	15.0:1	145	9.7	138.000
Benzole (high quality)	0.878	78-120°C (90% below 100°C)	13.4:1	165	12.3	152.000
Methyl alcohol (Methanol)	0.797	65°C	6.5:1	437	73	68.000
Ethyl alcohol (Ethanol)	0.794	78°C	9.1:1	368	41	92.000
Acetone	0.798	56°C	9.5:1	239	25	98.500
Ether	0.714	34.5°C	11.2:1	150	13.4	107.000
Water	1.000	100°C	-	972	-	Nil

 

Petrol (aviation base stock) - Petrols vary widely in boiling range and anti-knock value. Octane number if typical aviation stock is about 75.

Benzole (high quality) – Benzoles subject to variation. Anti-knock value indeterminate (see note 3)

Methyl Alcohol (Methanol) - Anti-knock value indeterminate (see note 3)

Ethyl Alcohol (Ethanol) - Anti-knock value indeterminate (see note 3)

Acetone – Anti-knock value about 100 Octane

Ether – Very poor anti-knock value. Can only be used sparingly. Used to improve volatility.

Water – Used with alcohol fuels to increase the latent heat still further

 

 Notes:

1)      The question of solubility of one component in another is rarely an involved one. Although it requires careful consideration it is not normally a serious difficulty

2)      In tables such as this, it is usual to give the latent heat of the fuel alone. However, it is considered that the latent heat per lb of air in a “correct” mixture is more significant in practice

3)      The anti-knock values of benzole, methanol and ethanol are normally quoted as being 90-100 Octane. In most racing motor-cycle and car engines, however, the effective anti-knock values of these fuels are very much higher indeed.

Blending Fuels – the 1950’s way

I thought this blog post would give an insight to the method used for blending racing fuels in the 1940/50’s. The guidelines for fuel blending come from Jimmie Simpson’s notebook  (Jimmie Simpson Blog post)used when he was competitions manager of Shell-Mex and B.P. Ltd.

The blending process:

1)      Inspect the 50-gln. Barrels to see that they are thoroughly clean and unlined – for this inspection a special inspection lamp is being sent to the depot.

2)      Clean all equipment that is to be used (measures, funnels etc) by washing with spirit or benzol (dependent on the type of fuel being blended).

3)      Calculate the quantity of components required and stack the cans in separate piles near the blending barrels.

4)      Take a sample of each ingredient from the bottom of the packages by using the valinche and test the specific gravity (see table for specific gravities)  

5)      Calculate the specific gravity of the resultant mixture arithmetically (see example)

6)      Calculate the best means of having complete blends in each of the barrels at your disposal (i.e. halve the components and place half in barrel 1 and half in barrel 2, when blending operations commence).

7)      Start blending by filling into the barrels the ingredients having the lowest specific gravity. Then add alcohol and benzol alternatively. These latter components, having a greater gravity will fall to the bottom of the barrels, whilst the lighter spirit will tend to rise, and in so will mix to a certain extent with the other ingredients. As cans are emptied, stack on one side and leave until the blend is completed, mixed and sampled. Any error in the resultant specific gravity can then be checked against the actual components used. When figures are agreed, remove the empty packages and commence canning of the blend.

8)      Use either a 2-gln. or a 5-gln. measure each time to ensure that the correct quantity has been used. (Do not pour straight from the cans, as it is impossible to say whether they contain the exact tow gallons.)

9)      In adding the dye, care should be taken that it is added a little bit at a time, during the actual blending, to ensure complete mixing.

10)   If it is necessary to add Castor Oil to the mixture, then the oil should be mixed thoroughly with part of the Methanol and/or Ethanol, and added to the blend; vigorous stirring should accompany this process. A milky, frothy mixture will result when the Castor Oil is added to the mixture, but this will disappear when the mixture is assed to the bulk blend. The resultant fuel, however, will not have the same crystal clear appearance as a fuel with no oil addition.

11)   If, on the other hand, it is necessary to add a mineral oil to the mixture, e.g. Triple Shell (Heavy), the same process should be carried out, but the oil should be mixed with the benzol or petrol (preferably the benzol) and not to the alcohol.

12)   When the blend is finished, replace the bung and roll the barrels for a short while to ensure that the components are thoroughly mixed – alternatively stir the mixture with a clean, un-painted wooden or metal dip-stick during blending, which will reduce the rolling period required to a minimum.

13)   Replace the barrel on the stollard and by using the valinche take a sample from the bottom of the barrel and check for appearance and take the specific gravity. This latter should be the same as was calculated in (5) by calculation, but if there is a discrepancy check through all the process and make sure that the correct quantities have been added: also check your calculations.

14)   When the gravity is agreed, canning operations may be started (each can should be carefully examined beforehand to see that it is perfectly clean).

15)   When all filling is finished, carefully clean and dry the hydrometers and keep an exact record of the blend made in a special book, together with dates, quantities of ingredients, etc.

16)   If at any time it is necessary to blend a special mixture for anybody, full details are to be kept, together with the person’s name and performance of the fuel in the engine concerned.

Specific Gravities @ 60°F

Methanol                            .796

Ethanol/Benzol                 .820/.825

Ethanol/224                        .783

Ethanol/Shell                     .783

DTD 224                                .736

Shell                                      .736

Benzol                                  .860/.870

T.T. Benzol                          .873

Swan                                     .685

Acetone                               .796

Water                                   1.000

Shell Castor Oil G              .950

 

Specific Gravity Correction factors per every 1°F are:-

Petroleum Spirit of Specific gravity           .675/.714                             0.0005

do. do.                                                                  .715/.750                             0.00045

do. do.                                                                  .751/.800                             0.0004

Alcohol                                                                 .780/.820                             .0005

Benzol                                                                  .860/.880                             .0006

Examples:-

Spirit of specific gravity .730 @60°F – to calculate its specific gravity @ 50°F :-

Temperature difference = 60-50 = 10°F

Correction factor - .00045 per 1°F

0.000045 x 10 for 10°F = 0.0045

As temperature is lower than 60°F, add factor to specific gravity @ 60°F: .730 + .0045

= .7345 – Specific Gravity at 50°F

 

Spirit of specific gravity .730 @60°F – to calculate its specific gravity @ 70°F :-

Temperature difference = 70-60 = 10°F

Correction factor - .00045 per 1°F

0.000045 x 10 for 10°F = 0.0045

As temperature is lower than 60°F, subtract factor to specific gravity @ 60°F: .730 - .0045

= .7255 – Specific Gravity at 70°F

 

Method of calculating specific gravities:-

Note:    For the purposes of these examples gravities are quoted at 60°F. It should be remembered that should the temperature be below 60°F the component will have a higher specific grvity and if above 60°F, the component will have a lower specific gravity.

811

Specification:                     %                            S.G.

Methanol                            80x                         .796                        63680

Benzol                                  10x                         .862                        8620

Acetone                               10x                         .796                        7360

                                                                                                                79960

Specific gravity of resultant mixture is .7966 by calculation

D.4.

Specification:                     %                            S.G.

Ethanol                                 70x                         .820                        57400

Benzol                                  20x                         .860                        17200

Shell                                      10x                         .736                        7360

                                                                                                                81960

Specific gravity of resultant mixture is .8196 by calculation

 

 BP Racing Ethyl

Specification:                     %                            S.G.

Methanol                            97x                         .796                        77212

Acetone                               3x                           .796                        2388

                                                                                                                79600

Specific gravity of resultant mixture is .796 by calculation

 

Dye addition = ½ pint Master Dye Solution per 100 gallons

=284 ccs. Master Dye Solution per 100 gallons.

=10 fluid ozs. Master Dye solution per 100 gallons.

Dye addition per gallon = 2.84 ccs. Master Dye Solution per 1 gallon – say 3ccs Master Dye Solution per 1 gallon.

Jimmie Simpson – motorcycle racer and Shell-Mex & B.P. Ltd racing manager

This is the first of a few posts I will do which relate to Jimmie Simpson.

Jimmie is best known for his motorcycle racing exploits. He was the first man to lap the IOM at 60, 70 and then 80 mph. In recognition of these feats the Jimmie Simpson is awarded annually at the TT for the rider who posted the fastest lap of the week.

Jimmie’s first TT was on a Scott in 1922, but from 1923-28 he raced for AJS. From 1929 he joined the Norton team.  Even with many wins all over Europe and the lap records at the IOM, a TT win eluded him. Jimmie’s final year racing was 1934. In the winter of 1933 Jimmie became racing manager for Shell-Mex and B.P. Ltd. Shell-Mex still allowed Jimmie to do one more year of racing. At the 1934 TT Jimmie had his best ever with two second places in the Senior and Junior and a long overdue victory in the Lightweight on a 250cc Rudge.

Jimmie Simpson

Throughout his racing career Jimmie was European champion 5 times (350cc in 1924, 1927, 1933 and 1934, and 500cc in 1926), as well as winning many important races.

His contribution to racing is better documented elsewhere, but the blog posts I will do on Jimmie is based on his role as racing manager for Shell-Mex & B.P. Ltd. Jimmie stayed with Shell for the rest of his working life and in his role was involved in many important aspects of both motor car and motorcycle racing. It is through Jimmie’s notebook from his time as Shell-Mex racing manager that I hope to give an insight into the role of a competitions manager of a major oil company.

Jimmie Simpson's notebook from his time as Shell-Mex & B.P. Ltd. racing manager

Valves for the Hopper special

I thought I would do a little blog post about the latest work that has been done on the Hopper special’s Lea Francis engine.

It is not often when you get original correspondence from the engine builder about how he built his engine. In this case we were very lucky when it came to the Hopper special valves.

Below is a picture of a standard Lea Francis valve which is suitable for the 1500cc Dirt Track engine.

Std Lea Francis valve

The next couple of photos show a letter and drawing from Ian Hopper about how he wanted to modify the valves for the Hopper special.

Letter from Ian Hopper

Drawing showing modifications to the inlet valve

Given Ian wanted to build his engine this way, it was only right to remove all the valves and machine them as he intended. The photo below shows the newly machined valves to Hopper specification as well as some of Ian’s old valves.

New valves modified to Hopper's specification along with some of the original valves

The final scan is of Ian Hopper in his mk3 Hopper special and is from an advert in this years’ Classic Monte Carlo rally programme.

A picture of Ian Hopper in his mk3 Hopper special at the Rest and be Thankful

Biscuits and Motorcyclist from Glasgow

I know it is a strange sounding title for this blog post, but if we go back to the 1950-60’s to the outskirts of Glasgow, we find a link between the two.

As you may have seen in some of my other Blog posts, Joe Potts ran a very successful motorcycle racing team from Bellshill. Joe’s business interest went further than bikes, as he also ran a successful garage, filling station and funeral parlour. Joe was well liked by all who worked for him and was known for looking after his staff.

One such way Joe looked after his staff was to give each of them a hamper at Christmas. This is where the biscuits link comes in.

Tunnocks which are based round the corner from Bellshill in Uddingston have been a family bakers since 1890. It was in the 1950’s that Tunnocks expanded and started to produce the products they are now famous for, for example the caramel wafer bar, teacakes, snowballs etc.

So when it came to Christmas, Joe made sure that the hampers for his employees were filled with Tunnocks products.

This isn’t where the link ended. During the 1950’s, motorcycling clubs were very important in Scotland, and one of the most famous from the area was the Avon Valley club. At club nights it would be common to have special events. One of the most influential members of the Avon Valley club was Charlie Bruce, who spent much time with the racing team at Bellshill. Charlie had arranged the likes of Bob McIntyre to speak on club nights.

On one occasion the Tunnocks link was again utilised, as a tour of the Tunnocks factory was arranged for the members of the Avon Valley club to go on a tour of the factory.

Tunnocks themselves have been involved in racing. For example, Boyd Tunnock who runs the company competed at the Bo’ness hill climb in 1962.

So when I was in Bellshill this last week I had to take the opportunity to visit the Tunnocks factory - and what a wonderful factory it is! The reception area is beautifully laid out with wonderful paraphernalia relating to the history of Tunnocks.

I am very pleased to say that Tunnocks are very happy with their association with the local business which was run Joe Potts. With this in mind Tunnocks were happy to donate some caramel wafer bars to the Joe Potts collection of racing bikes/cars. These caramel wafer bars will be available to members of the public who visit the Joe Potts stand at the Bo’ness revival hill climb in September. Be warned, they will be given out on a first come first serve basis, and given how tasty they are, I can’t see them lasting long!

OHC Velocette – it could only be in a shed in Yorkshire

I was ferreting around West Yorkshire, when I ended up next to the Emley Moor radio mast. When I see that mast it means only one thing, I must go and call on an old friend who is in the vicinity.

When I think of Velocette ‘Specials’, bikes made in Yorkshire spring to mind. When you think of Yorkshire Velocettes, the name Swallow also springs to mind. If you combine Yorkshire, Velocettes and Swallows you end up with some interesting machines indeed.

Alec's badge of honour

The Swallow name is synonymous with Velocette, due to Ken Swallow being a Velocette dealer for many years in Station Road, Golcar. It was one of Ken’s son’s Alec that I went to visit.

As the van was parked on the main Kirkburton road, I immediately heard a single cylinder fire into life. Knowing this could only be Alec, I had to run to his house before he disappeared off on something tasty.

It was indeed Alec who had just finished sorting a Velo for a customer of his and was about to ride off to Leeds to deliver it. Seeing as we had called, Alec was quite happy to delay the trip so we could spend half an hour or so in the shed.

The Velo Alec had just finished rebuilding for a customer

If you asked Alec how he spends his time, he would probably say “pottering”. Now if Alec’s time is spent pottering, it is the sort of pottering I approve of!

Every time I visit Alec he seems to have been up to something new. Alec ‘s engineering work is not in the style of many – i.e. open up the cheque book and pay for a collection of parts. Alec is a man after my own heart – he enjoys building specials, and he does it himself. After all this is Yorkshire.

It was only a quick trip to see Alec, so I only got chance for a brief natter and to take a few photos of what he’s been up to. To quote Alec, “it’s not one for the purists” – and that is what makes it far more interesting!

Always something exciting to see - Alec's new SOHC Velo

The basis for the engine is a trusty Venom, but it is fair to say it looks a little different. When you consider that Alec has re-vamped the valve train and converted the engine to a SOHC setup, it is quite remarkable that the engine still looks so similar to a standard Venom. It is a neat setup that Alec has come up with and is pleasing on the eye. The camshaft is driven by a chain running from the original cam gear in the timing case, which still provides the required 2:1 reduction. This means that an equal number of teeth can be used on the drive sprockets, which in turn allows the chain-wheel in the head to be of a small diameter. This makes for a light and attractive looking top-end.  You might notice that ‘mk3’ is stamped on the cam chain cover – and for good reason. Alec has built two over-head-cam Venoms before – one a DOHC and one a SOHC.

 You see what I mean about Alec liking to do things himself?

 These earlier machines were built during Alec’s racing days in the 1960/70’s. It was not just special engines that were made during this period, as he also built his own frames (including a spine frame for a Velo based upon the Loch Ness monster) and built his own fibreglass fairings, tanks etc.

It is not just this new mk3 SOHC Venom engine that Alec has been working on. He has fitted the engine in a standard Velocette frame, which he has had to modify to accommodate. I was really impressed to see that Alec had made all the moulds and then done the fibreglass work for the tank, seat and oil tank on this bike. You will also see the interesting brake on the front of the machine. This is another leftover from Alec’s racing days, which uses a hydraulic conversion brake plate in a Norton hub.

A very neat looking machine

Alec's very nice hydraulic brake conversion

So that was my short trip to see one of the characters of the Yorkshire Velocette Mafia. It was only a fleeting visit to Alec’s so I have only kept this post short. But next time I am up I will go into a few other Velo specials that Alec has made over the years.

Alec even made the tanks, seat and mudguard for his new special