WW1 Dennis truck find

[Great War truck]

The grommets were next. The plug was cut from a piece of ash and wrapped with foil this time and the same process was followed.

 

 

 

 

This time the resulting blanks were shaped using the belt sander set at an angle to get the taper.

 

 

The whole lot were then assembled into the tube using Araldite before being sanded to shape using a Dremel with sanding drum and finishing off by hand.

 

 

 

A few holes were filled with Isopon

 

 

and the whole lot was given two coats of paint.

 

 

Another part ready to fit!

[Alex van de Wetering]

The finished cardboard part looks excellent! Well done and good to see the effort to save the original part. Sometimes simple and cheap material are the best solution.

 

In a few weeks you'll probably show us how to glue your shattered windscreen back into one piece of glass:D

 

Alex

[Old Bill]

Fortunately for us, safety glass hadn't become common so the lorry is completely open and that particular need doesn't arise! :-D

 

Since completing the tube, I have been tinkering with the carburettor. As mentioned before, I am stripping down one and fitting the parts to another incomplete body of the correct size. This has turned out to be a more expensive exercise than expected as Claudel was French and so it is all metric and we are not tooled up for that! Dad has bought some taps and dies and I have ordered some more change wheels for my lathe to allow me to screw cut metric pitches. Always something!

 

One thing still remains a puzzle and I am hoping that you chaps can help. The manual describes the correct jet as a 'number 130'. The jet I have extracted from my donor carb is clearly marked '135'. Can anyone tell me how the Claudel numbering system worked and whether I will have to make a new one or not? If I have to make a new one, It would be nice to know what the numbers actually mean so that I can drill it the right size!

 

All thoughts and comments would be much appreciated.

 

Steve

[Stormin]

Being as the rest of the carb is metric I suspect it will be the jet bore in hundredths of a millimetre.

Carb jets tend to come in steps of size, 5 being the step value. So the jet you have is one size larger than 130 specified i.e. very close. When it was new! Dependent on use and corrosion that jet size may be very different from the original specification now.

I would be tempted to try the engine running with the jet you have there and see whether it runs rich or lean then adjust jet sizes based on your findings.

Although the engine may be to original specification, modern fuel is very different. The other variable likely to affect engine tune is the custom made exhaust you have. The airflow charactersitics could be very different.

I would say get the engine up and running on basic settings then get it properly tuned using modern equipment (crypton, gas analyser etc). I know it's not the traditional way but it's a better way of getting the engine running efficiently and making sure the engine enjoys a long life.

[Asciidv]

I always thought the jet number related to flow rate, with a 135 jet passing a flow of 135cc per minute at a specified head. You therefore need a look up table between the jet number and hole size as it is not simply proportional.

 

(...and I few minutes after I wrote this, I read;

 

"First it is to be noted that in a car or lorry engine practice, carburettor jets are graduated in diametrical measurements of the metering orifices, the progressive numbers varying generally in hundredths of millimetres ‑ one millimetre being called 100. In speaking, for example, of a 90 or 95 jet, 0.90 or 0.95 of one millimetre (namely 100) is meant and in a similar manner for a 115 or 120 jet, 1.15 or 1.20 millimetres is meant respectively. "

My excuse is that I come from a motorcyle background with AMAL carburettors where it is definitely flow rate which the jet size number refers to!

Certainly a little richer mixture will be on the safe side, as Norman suggested. I have always relied on a 'Colourtune' glass spark plug to gauge mixture. With most early Dennis fire engines having twin plug heads it is easy to replace one of the plugs with the glass plug and still be running with all plugs of the correct heat range.

 

 

Barry.

Edited August 6, 2010 by Asciidv
Proved wrong again

[Old Bill]

Thank you for your thoughts chaps.

 

I have just checked the orifice size in the 135 jet and a number 55 drill pushes in nicely. That is 0.52" or, 1.32mm. Our spare carb has a 120 jet in it which will take a number 56 drill which is 1.19mm. Finally, Ben has kindly loaned us a carb to use as a reference. That has a 160 jet in it which takes a 53 easily or almost a 52 drill. These are 1.51 and 1.61mm so I think you have it, Norman. I agree that it isn't worth making new jets at this stage so we will just run with the 135 and see how it goes (assuming we can start it!)

 

In my pottering this evening, I have looked at the fuel pipe connection and that is 5/8" UNF! Goodness knows why but I don't have that size so I will have to make a new one 5/8" BSF which is the size specified on the fuel tap. Of course, it needs a piece of 13/16 AF hex brass, which I also don't have, so I will have to make some of that first. Once all that is done, I can make the nut and olive. This really is a very silly pastime!

 

Steve

[Great War truck]

We had a go at the Headlamp Brackets yesterday. The first thing was to turn up to "blanks" for the part of the Headlamp Bracket. These were reduced to 1/2" diam at the end to take the fixing in the Headlamp and also a taper running into it.

 

 

These were then to be bent over a former - but had to be red hot to bend easily,

 

 

 

The former was (foolishly) made out of wood with a plate screwed to it to secure the end of the tube as it was being bent around.

 

The wooden former was shaped to equal the inside of the "U".

 

 

The steel blank had to be red hot to bend - but it became far more aggresive in burning the wooden former than we anticipated and consequently burnt itself deeply into the former - resulting in a tighter final radius than was required.

 

 

 

The steel was very easy to bend around the former when it was red hot - but unfortunately, the radius of the bottom curve ended up tighter than we required and what was anticipated, just because the steel burnt itself tighter into the wood than we wanted, so that we ended up with a lamp bracket that is just too small! A steel former must be made up to correct this - the bracket can be made red hot again and beaten around the correct shape former.

 

 

 

[Stormin]

Did you try laying a piece of sheet steel between the former and the bar, bending it round along with the bar? The cold sheet metal should have protected the wooden former, if the bending operation was done quickly enough that it didn't heat up itself.

It will use a few pieces of sheet if you can't re-use them on subsequent bends but probably cheaper in steel than making a former specifically for those few radius bends.

[Great War truck]

Ah, you beat us to it. This is Headlamp Bracket Bending Former Mk 2! All it is, is the original Former with some 16 gauge mild steel wrapped around it to protect the wood from the red heat - and it works OK!

 

We semi-straightened the "U" that we made yesterday by getting it red hot again, and then re-bent it around the Mk 2 former.

 

 

 

 

We now have to make a second one for the other headlamp - hope it will be more straight forward now that we have "cracked" the method of doing it.

 

The bottom of the narrow parts of the "prongs" will be fitted with collars where they join the taper, and I then have to make the "arms" which will be welded to the bottom of the "U's" to extend to fixing bolts on the chassis.

 

 

 

[wildside]

Im impressed by your railway layout is it very extensive?

[Minesweeper]

The Railway is 7 1/4" Gauge and circles the house - about 350ft or thereabouts around. Has given us a lot of fun and we use it to help raise a few shillings for village charities. Does not get a lot of use at the moment as the Dennis has rather taken over...............

 

Tony

[Asciidv]

The Railway is 7 1/4" Gauge and circles the house - about 350ft or thereabouts around. Has given us a lot of fun and we use it to help raise a few shillings for village charities. Does not get a lot of use at the moment as the Dennis has rather taken over...............

 

Tony

 

It's best to steer clear of these Dennis people. They are always on the wrong side of the tracks..

 

 

 

.

[Minesweeper]

Nice one!

 

Tony

[Great War truck]

Surely that leaves me on the right side of the tracks? Its the ones who live up the hill who are on the wrong side.

 

Anyway, Tony had a very productive day today:

 

 

So now we have a matching pair!

[Great War truck]

As you may have guessed, Steve has been working on the carburettor recently. We were very fortunate to be able to buy a whole (more or less) 32mm carb and and a 28mm carb body at the spring Beaulieu this year. Following that, a few weeks ago, another 32mm turned up on our old friend 'Ebay' and that was purchased very reasonably too. As it was complete, Steve decided to tackle this one. As you can see, it was pretty filthy but basically all there.

 

 

First job was to strip it down and with a little heat, this was successfully accomplished.

 

 

However, the bolting flange had the holes at the wrong pitch and needed to be replaced.The flange is screwed onto the body casting and then soldered but in spite of plenty of heat, it refused to budge

 

 

so Steve decided to use it as a donor to rebuild the 28mm body instead which had the added bonus of being exactly the right size for the engine. After an hour or two with a rotary nylon brush in the pistol drill these were the components.

 

 

More to follow.

[Great War truck]

The first part to be made was a replacement choke. The original had survived but had had to be cut off to remove it.

 

 

A replacement was made and fitted.

 

 

Next was the new mounting flange. Many years ago, Father had picked up a piece of brass from the local second hand tool shop for a few pence. It turned out to be exactly the right size and was quickly milled square, drilled and bored.

 

 

 

Something we have only just found out was that Claudel (of Claudel Hobson) was French so the whole carburettor is metric. Now we are not tooled up for metric at all so it began to cause some problems. The mounting flange has an internal thread of 44mm x 1.5mm pitch. The only way to create this was to screw cut it so Steve had to go out and buy two 21 tooth gears for the leadscrew on his lathe. Oh well. They are now in stock for next time.

[Great War truck]

The pin to locate the float chamber lid was missing so that was drilled out and replaced.

 

 

Then came the lid itself along with the bob weights and pivots. As you can see, the holes and the pins really had suffered some excessive wear and it was a bit of a puzzle to know how to tackle them.

 

 

In the end, some bushes were turned up and soft-soldered into the holes before drilling through at the final size of 2.1mm.

 

 

 

New pins were cut and crimped at the ends to retain them whilst the bob weights were reversed to wear on the other side.

 

[Great War truck]

This pic shows all of the pieces that were made up for the job including a lock nut and also a pipe connection. This was M12 x 1.5 one end and 5/8 UNF the other. The metric thread was non standard and a Dennis wouldn't have had a UNF thread on it so it was replaced with 5/8BSP. We did have to buy a special metric tap though.

 

 

It was finally reassembled this evening

 

 

 

Now there is just a water pipe to make before the engine can be run.

[abn deuce]

What is the purpose of the exposed shaft coming up through the float chamber ?

[Old Bill]

That is the end of the needle valve controlled by the float. When starting, it can be lifted off its seat to allow the carb to flood and hopefully ease the starting process.

 

Steve

[abn deuce]

AH I see now , had thought a visual on float level but that seemed a bit odd , but a assist on starting is a good thing too.

[Gordon_M]

.. and when you take the truck to a show, some pillock is going to say;

 

lucky it had the original carb with it, and in such nice condition too.

 

 

 

Gordon

 

( off to play pre-WW2 Dodge steering column ...

 

... later, column played with, result - a draw, horn button still needs work)

Edited August 14, 2010 by Gordon_M
spelling, must do better

[ajmac]

lucky it had the original cab with it, and in such nice condition too.

I would have thought that is what all the work is aimed at! Rather than .... Oh I see you had to make a replacement for that...

[mattinker]

That is the end of the needle valve controlled by the float. When starting, it can be lifted off its seat to allow the carb to flood and hopefully ease the starting process.

 

Steve

 

If i remember correctly, they were callaed ticklers,I'm not that old, but I think I came across them when I was an adolescent in the sixties, it may have been on fishing boats.

 

Regards, Matthew

[cosrec]

Some old motor bikes had them ticklers on them BSAs ??

By the way when they start handing out medals as big as dinner plates for dedication to your hobby i think you guys will be at top of list Brilliant