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WW1 Thornycroft restoration


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Yes, we do have a manual but it is not as good as the US Army ones. Still very helpful though. Over the years, I have managed to photograph all of the survivors to some extent so we are reasonably well off for data. Also, at the time I bought the remains, I lived in Southsea, just along from Eastney bus depot where the Portsmouth Corporation kept their J-type bus. I used to wander along of an evening and spend a couple of hours sketching and measuring. I did that for weeks and have quite a folder of information. Now all we have to do is find the time to get on and do it. Must finish the Dennis first though!

 

Steve :)

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That was a nice surprise. It's a small world! I asked Steve what he had left over after he had sold his Thorny. It turned out to be only a single item, a water pump impeller which is now safely on the shelf ready to replace the cracked one Father has found in our engine!

 

Steve

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That was a nice surprise. It's a small world! I asked Steve what he had left over after he had sold his Thorny. It turned out to be only a single item, a water pump impeller which is now safely on the shelf ready to replace the cracked one Father has found in our engine!

 

Steve

 

I put something on the Dennis Link a month or two ago - "Meant to be" - is this another example of that?

 

Tony

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I picked this up from Nigel at W&P yesterday:

The tail lamps are a bit less common. The one on the Dennis is just post war, while this one appears to be a wartime one. I will tidy this one up for the Thornycroft i think - but we dont need it in a hurry. Good to meet you at last Nigel.

I also bought at W&P a couple of plain 2 gallon petrol tins which are very similar to the correct WW1 pattern that we need for the Thorny. Although looking a little shabby, both are shiny on the inside and no sign of rot, so ideal really.

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  • 3 weeks later...

Tony is back from holiday and couldnt resist picking up the Water Pump again to see if he could finish taking it apart.

 

The body of the pump consists of two iron castings with one faced up to the other. They are held together by long 5/16" Whit studs screwed into the back casting which is the part of the pump that actually bolts to the engine. There are clearance holes in the in the other (front) casting so that this casting can go down over the studs. The aluminium shroud also goes onto these studs and nuts then go on the studs to hold the three parts together.

 

He tried earlier to get the pulley loosened on the shaft as this must slide down the shaft to come off with the shroud but it is stuck tight and not easy to get at to free it. So he decided to tackle the job from the other side by removing the studs so that the body can be taken apart in the hope then that the pulley can be removed on its shaft from that approach. The studs were well rusted in but persistence with the blow torch and Plus Gas eventually did the trick. Two of the studs are stubborn and he left them to soak in Plus Gas - and if needs be, will put the blow torch on them again.

Separation of the two iron castings did not allow the shaft and pulley to be pulled through from the rear, as the pulley is larger in diameter after all than the centre hole in the casting.

So the next job is to get the impeller off so that the shaft can be pulled forward to come off the front casting. That will need a good wire brushing as I cannot see how it is fixed to the shaft.

There is a cross hole in the pulley "boss" which looks as it was meant for a Taper Pin but there is not one there.

Interesting that the threads on the Thorny are "Wit" whilst the Dennis was all "BSF".

 

 

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The water pump is finally apart! If the shaft was originally salvageable - despite its heavy rusting, it no longer is as the threaded end has taken a bit of a beating in getting it apart. That is not a problem as it will be a simple turning and threading exercise with a couple of keyways to cut to make a new one but we do like to keep original parts where we can. The third and fourth photos in this series show the broken main casting - I wonder if it was broken previously when someone was trying to get the pump apart?

This series of three pictures show the broken shroud. The bit of 1/4" bar protruding into this is now clearly visible - it is solid and not a pipe but I still cannot work out what it is for. Perhaps Richard P can throw some light on this?

Both broken castings now need to go to the Pattern Making Department in Leicester so that patterns can be made from them for new castings!

The first two pictures show the Impeller - Tony had a quick look for the spare that we have in stock but cannot readily find it. That can wait until the whole team is here at the end of the month when all the trucks will be out and when we can get to the shelves at the back of the shed!

The last picture shows the inside of the main casting which bolts on to the engine - the casting is sound but will want a little attention to clean it up!

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Great to see you guys dive into the next "big" project, and its all done in a relatively down to earth low budget manner which really leaves no excuse for us with "newer" and far less daunting projects!!

Incidentally I have noticed that Scammell Pioneers are almost entirely BSW whereas the AEC Matador is pretty much all BSF!

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The penny has finally dropped! The mystery bit of 1/4" steel bar mentioned in note 57 above is a locking pin. It was designed to screw down on top of the Gland Nut to stop that from turning. The instruction on the brass label on the pump has given the game away as it says the locking pin must be released before tightening or looseneing the Gland Nut!

 

Tony

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The penny has finally dropped! The mystery bit of 1/4" steel bar mentioned in note 57 above is a locking pin. It was designed to screw down on top of the Gland Nut to stop that from turning. The instruction on the brass label on the pump has given the game away as it says the locking pin must be released before tightening or looseneing the Gland Nut!

 

Tony

 

Looks like someone previous didn't follow the instructions then hence the bend in the pin.

That shroud piece looks like it'll take a bit of work with pattern making, it's a very thin section with not much room for error. Do you ever consider using the original parts as patterns, albeit repaired and built up to allow for shrinkage, rather than making patterns from scratch?

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Steve is the best person to comment on the ali shroud casting as a potential pattern - perhaps, too with some input and advice from Gordon - but the side ali radiator castings on the Dennis were done that way. I repaired one of the very rotten originals as best I could for a pattern and added a bit of 1/4" - may have been 3/8" plywood on top and bottom to allow for vertical shrinkage. the horizontal dimension did not matter - and that worked very well.

 

The only thing that I would say is that the shroud is in very poor condition with quite a lot missing and is very brittle.

 

Tony

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Many of those bits are humble cast iron, and while many of them could be used as patterns, it is generally so much simpler to make new patterns.

 

The contraction on that stuff is 1/8" per foot, so a casting that has to end up a foot across starts off as 12 1/8" at least Simple blocks, mouldings, and things that are 'easy' tend to work as patterns, anything complex, thin section, or with tricky radii tends not to. As an example, and I know there is one in stock, it would be impossible to use the broken impeller as a pattern, and difficult to use the broken housing.

 

 

That new laser-scan and 3-D copier process would be ideal for this stuff - either making the item itself or making patterns. It would be easy to laser scan that housing, replace the broken section in software, add a contraction allowance, and produce a pattern that would work for making a casting.

 

Bit expensive though.

 

Gordon

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Many of those bits are humble cast iron, and while many of them could be used as patterns, it is generally so much simpler to make new patterns.

 

Gordon

 

Thanks Gordon. I couldn't have put it better myself! Years ago, four of us clubbed together to get patterns made for the radiator. Hampshire County Museums Service were one of the four and they provided a gash radiator to use to make the castings. Their parts were reworked to provide core prints and new core boxes were made. We each had a set of castings from them and the museum holds the patterns still. The Dennis top and bottom tanks are more complex and can't be used in the same way so I will have to make them up complete. These water pump bits are in the same league I think so I won't be able to use them.

 

At the moment, though, I am still finishing off the Dennis!

 

Steve

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... that you got that spare impeller. I won't try to describe the amount of pattern equipment you need to reproduce one of those, but it wouldn't be simple.

 

That said, if the impeller was the challenge, I'm sure you could find a modern one and just bore it to fit.

 

I have reproduced the Pioneer compass mounting bracket for DUKW and Weasel. I had to get a wooden master pattern made, then an aluminium working pattern, but all the people who did that for me are long gone to the big pattern shop in the sky now. I'm impressed by the range of facilities you have either cobbled together ( you know what I mean ... ) or co-opted.

 

Pattern making in cast iron and bronze, tyre press for changing solid tyres, the correct nuts, bolts, and washers, regardless of difficulty in obtaining, even carting an engine halfway round the world :shocked:

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Impellers I have found are probably the easiest part to make with modern technology

 

I found the cast Tender water pump impeller to have many cracks and so have fabricated a new one from stainless which is very easy to do if you are able to draw in CAD and have access to a lazer machine. The blades are curved as the original and are tabbed to fit into the slotted front and rear impeller plates, just hammer together, weld and finish machine, much easier than making a pattern and casting.

 

The image below shows the assembled lazer parts, final welded and machined impeller plus the original.

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Impeller1.jpg

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That's a nice piece of work Tom. More than one way of skinning a cat!

 

I did make the pattern for the Dennis impeller and that worked out quite well in the end. We are fortunate in that we have a spare for the Thorny. At least, if we could find it. We haven't seen it for ten years and it hasn't turned up yet!

 

Steve

 

 

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Tony has had another look for the Water Pump Impeller - but still no luck! However, he did find the two Thorny fans that we acquired some years ago for this restoration - one original but slightly damaged complete with the Thornycroft Part No. cast in it (came from Mike Jones, found at an Autojumble. Mike is always keeping his eyes open for us) and the replica from Ron Turner who restored two J's some years ago.

 

Both have the fixing holes already drilled in them and they both fit snugly to the drive plate from the water pump!

 

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  • 2 weeks later...

After a further search, the Impeller casting was found on a back shelf, where it had been safely tucked away several years ago. As and when time permits, it can be machined up ready to fit. The photographs show it along side the cracked original.

 

 

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  • 2 weeks later...

Tony has had some time after painting and decided to have a go at removing the water jacket covers on the rear part of the engine. We have been squirting the nuts with Plus Gas for some time - that has paid off as all of the nuts undid easily.

Took the lower cover off first - and revealed the water space jammed solid with scale and rust. Then took off the top cover to reveal the top of the scale level - the space behind each cover is all one so that it is one water jacket with two covers. There are two similar covers on the other side of the cylinder which will have to come off in due course.

He dug out the scale and rust as far as possible through that exit - but there will be more to come.

 

 

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The level of simple patience exhibited here, and in the Dennis thread, is awe inspiring. Not to mention the skills. You need the skills of a machinist, a foundryman and metal fabricator, as well as a mechanic... and I suppose acquiring those skills is the true joy in it. Seeing this in such detail is both encouraging and discouraging to a person who has long held a desire to do something like this. If I started now, I might just reach apprentice level at some of those skills before I died or old age made the work impossible. No matter what, these are truly remarkable journeys and I am grateful you make a place for us to ride along.

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Thanks, Jim - those are very kind and generous remarks. The three of us are all self-taught amateurs and when we talk amongst ourselves about the kind of information that we have put up on the forum, we do wonder if we are going too far and boring people with trivialities. We remain truly amazed that the number of "hits" on the Dennis thread has advanced so quickly and by so much and is now approaching the 200,000 mark so I guess that there must be a fairly wide interest in the story. We plan to continue the Thorny story in exactly the same way - unless Forum members say that they have had enough!

 

Tony

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