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WW1 Thornycroft restoration

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It has been quite an exciting day really.. Tim and I pulled the camshaft out and rotated it through 180° yesterday. Unfortunately, he then had to go home but this morning, we were able to put the engi

We haven't balanced the shaft. The rotation depends on how well I drilled the leather so there will be some variability in it. Hopefully, there won't be a problem but if there is, then I will have to

Thanks Tomo. I'll remember that! We have had a nice day., all bright and still and not cold. I have been pressing on with the hand controls and linkage. First part was to cut the throttle shaft a

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We have 1963 109 as well within the collection! I bought it about 25 years ago as that we needed something to tow the two Autocars around on a Trailer when we took them to "Meets". It is ex -RAF Regiment and had the equivalent of about 7K miles on the clock when I bought it - now reached about 27K only after all of these years.. Looking a bit shabby but dearly loved by us all!





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21 hours ago, Old Bill said:

We have 1963 109 as well within the collection! I bought it about 25 years ago as that we needed something to tow the two Autocars around on a Trailer when we took them to "Meets". It is ex -RAF Regiment and had the equivalent of about 7K miles on the clock when I bought it - now reached about 27K only after all of these years.. Looking a bit shabby but dearly loved by us all!





Stupidity! Not 1963 - should have said 1983!




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We are going to be in trouble here for going off topic - but very briefly, it did not have a stripe and was painted the standard "black and green" cam pattern when I bought it. It spent most of its service life with 16 Sqn Wildenrath as a "Tracker Radar Towing Rapier Rover" - Service No. 73KB70


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On 6/17/2018 at 2:38 AM, dgrev said:

Steve - I think in time you will agree that to have persevered with the Brighton run would have been a bad decision....

......Now you have no schedule, can get that engine running sweetly and can enjoy the rest of the restoration, other than the wings (mudguards) installation that is.



(Aussie one)

Thanks Doug. Yes, it wouldn't have made it and we would have spent a lot of money for nothing. We did play the same trick with the Dennis though and got away with it! We have now set ourselves another deadline as we have promised to take something to the 'Tanks and Trucks' do at Bovington at the end of August followed by a road-run to the Great Dorset Steam Fair. That will be a 140 mile round trip so it would be nice to get a few miles under our belts first!

We took the blocks down to Exeter to see our friend Dave who had very kindly offered to hone them out. I had never seen this done so it was educational as well. The honing head is made by Delapena and has an adjuster on the top to push the stones outwards. The result is quite a torque reaction which caused the drill to 'kick' as it went over bumps in the bores. It quickly settled down and Dave took out somewhere between one and two thou. The swarf was quite noticeable so it was certainly cutting!


He worked it up and down the length of the bores constantly to give a spiral cut without circular grooves





Once we got the blocks home, I set about cleaning and sealing up the crankcase starting with a coat of Hylomar on each valve follower. I don't want any more water getting in if we can help it.



I also cut a thin paer gasket to go under each block.


These were marked out by tapping around the edge of the block with a ball pein hammer.



The second piston went back and we were ready to try to refit the block.



I don't have any pictures of it at this time as we ran out of hands. Suffice to say that I got too enthusiatic and broke a ring which irked me in the extreme so we stopped for the day.


Sunday morning when I had got my temper back and it wasn't so hot, we had another go and this time, all was well. We just used the chain block to lower the block back onto the pistons whilst I squeezed the rings in one at a time.


The other two pistons were fitted, less one ring, and we are ready for the next time.


The replacement ring turned up today, £20.10, so finishing the reassembly will be the task for the next visit down South. In the meantime, still plenty of bits to do!

Steve  :)

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Nice work! Another trick you can do with the paper gasket is give it a quick coat of shellac just before you do the assembly when its still wet - this makes a nice seal and makes the gasket more durable. When I disassembled my big Wisconsin T-head many of the gaskets were original and done this way including under the blocks , the oil pan and the timing gear cover.


Edited by Tharper
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  • 2 weeks later...

We have been plodding on this week. I really want to get on with the engine but living 200 miles from the lorry does make it very difficult! I have been amusing myself by turning up two new carburettor jets slightly bigger than the original but smaller than the one I made when we tried to run the beast.DSCN7634.JPG.0b8e022bb2bd699b932b425faabd32dc.JPG



It is nice to get back on the lathe after all the heavy ironwork recently.

The next item has been the petrol tap. The one we fitted was a simple tapered plug cock which looks almost exactly like the one in the parts book. Unfortunately, despite my lapping it in it leaked very slowly. If we were running the lorry every day then we wouldn't even have noticed but because we leave the vehicles laid up for such long periods, we would have noticed the loss. To get over this, I decided to make a new cock but with a cork lining. I tried PTFE on the Dennis but I have learned that PTFE swells in petrol and the tap seizes. I have a cork lined valve which will fit the Dennis so I copied that.

First job was to turn up the body and machine flats for the bosses.



These were silver soldered of course!


I bored it out after soldering so there was no distortion.



Then the spindle, a nice bit of turning.



After drilling and tapping, the handle was screwed in.


Now for the cork which came from a sherry bottle. I drilled it through at 23/64" to give a slight interference on the spindle. High speed and low feed rate is the secret here.


Have you ever tried turning cork? It is evil stuff! I now resort to grinding it. I have made up a flat piece of steel which fits the nose of the Dremel and also the toolpost and, using a grinding wheel, can machine it at up to 0.010" each cut. It is quite accurate too.



I Loctited a driving pin into the spindle.


And after copious 3 in One oil on the cork, a working tap!


Well, for a while anyway. I was lazy and used a normal nut and washer on the cork. This meant that all of the drive was transmitted through the peg and it tore the cork up. I therefore made a fancy flanged castle nut and machined another cork which was composite this time.




This weekend, I have made up the tailboard catches. They are not something sensible like a peg in a hole but rather fancy flip-over catches, bent out of 3/4" bar. First task was to make a bending jig.



I heated the bar with the propane torch and it bent OK. The blacksmith's hearth would have been a much quicker heat source but that is in Devon waiting for me to build a blacksmith's forge. Another future project!



The bosses were turned up, had a flat machined on them and were then silver soldered into place.



The pegs were turned up and soldered into place as well.


Finally, I turned up the pivots. These are bolted to the tailboard through the middle using a 3/8" bolt with the catches free to turn on them.


Something else to fit once the engine is sorted.

I have been very highly recommended to wash the grit out of the blocks and valves with plenty of paraffin. This is a very sensible idea but I will have to take the first block off again to do it. Oh well.


Edited by Old Bill
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1 hour ago, Chris Hall said:

Would you mind posting some more photos of your dremmel/lathe attachment? I could use a similar device for a project I have.

I think that the post says that it is just a hole in a piece of plate. That certainly works. You can use the original plastic end nut / spanner, but it looks like Steve has machined a metal one with the right thread. 

If you have a 3D printer then there are some designs that might help: https://www.thingiverse.com/thing:2846032 as a random example. 

If money is no object: this machined aluminium routing adaptor might be a good starting point. The correct thread, with a split-clamp is probably optimal. 

If you are going to do a lot of grinding then it might be worth getting something with better bearings to make a dedicated grinder. One of the cheap eBay router spindles perhaps. 


Edited by andypugh
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Hi Chris.

This is what I have done although it is not very good, really. As Andy has suggested, I removed the plastic nut at the front of the tool and just mounted the tool through a steel plate.



I turned up the steel collar because there was not enough thread in the original nut to get a good bite.


The plate fits into my parting tool holder.


The whole arrangement is not really stiff enough but it was good enough for cork. If I were doing it again, I would cut the thread in a piece of 1/2" bar and grip that in the toolpost after screwing the motor into it. The Dremel bearings aren't good enough for any sort of repeatable accuracy but it did the job I needed. Good luck with yours!

Steve    :)

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I have a DIY grade Bosch POF500A router that I use as a die grinder (have a look on Ebay). I have both 1/4" and 6mm collets for it so can hold both router bits and grinding stones in it. There is a parallel section where it clamps into the router frame that is just right for clamping it to a lathe and the bearings are fine for light grinding.

If anyone is thinking of using any kind of toolpost grinder on a lathe, do go to some lengths to stop the grinding dust getting on the bed in particular but also anywhere there are parts moving against each other - which on a lathe is pretty well everywhere !  Even the chuck will not be improved by a sprinkling of carburundum grit.


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On 7/14/2018 at 9:40 AM, David Herbert said:

I have a DIY grade Bosch POF500A router that I use as a die grinder (have a look on Ebay). I have both 1/4" and 6mm collets for it so can hold both router bits and grinding stones in it. There is a parallel section where it clamps into the router frame that is just right for clamping it to a lathe and the bearings are fine for light grinding.

If anyone is thinking of using any kind of toolpost grinder on a lathe, do go to some lengths to stop the grinding dust getting on the bed in particular but also anywhere there are parts moving against each other - which on a lathe is pretty well everywhere !  Even the chuck will not be improved by a sprinkling of carburundum grit.


Also to note is the siteing of surface Grinders in proximity to lathes, milling machines etc... 

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We are making some progress again now. I am having a long weekend in Devon and started off yesterday by trial fitting my tailboard catches.


They were fine and Father will paint them shortly. Whilst I was playing with these, Father took the opportunity to replace some coach  screws I had fitted to the back of the seat. I had used metric ones which have hex heads as I couldn't find any proper ones with square heads until our good friend Mick had a rummage in his garage and came up with some. That little detail has now been corrected.!




Then it was on to the main project of the weekend which was to get the engine back together. Following some good avice, we took the block off again in order to wash it out with paraffin.. I really didn't want to do this but carborundum dust in the bore wouldn't have been good. I started by taking the valves out whilst it was held solidly down.



We then put it in a steel drip tray and squirted it with new paraffin. This worked well and the debris shows that it was worth doing.



After the performance with the broken piston ring, Dad went and bought a ring compressor. This worked well to start with.


However, we met a snag in that as both ends of the tool were riveted to the tensioning mechanism, there was no way we could get it off!


Then our pal, Dave who honed the bores originally, came up with this tool. His band wasn't long enough but I soon made up another and it did the job even better. After getting the rings in, I could remove the band as well!


Both blocks on and reassembly has continued all day.




The engine is now reassembled and we have changed the oil again. It was pretty black. We filled it with water and, interestingly, all of the flanged water joints were leaking all over the engine and these were joints we hadn't touched.. I put a spanner on the nuts and all of them moved by half a turn. This was a surprise but once tightened, the leaks stopped. Even the jubilee clipped hose joints remained tight so in the end, all was well. I had fitted my new petrol tap so Dad put a couple of gallons in and I gave it a swing. It fired on the second revolution, much to my surprise and ran on for a while. It sounded rough and smoked a lot but it was going. We stopped it after a few minutes and I tightened up a leaking oil pipe joint which had also relaxed like the flange joints. Very strange. I fitted the smallest of my new jets and swung it again and away it went. This time it accelerated a lot better and idles faster with the leaner mixture so a win all round and we are very pleased. The proof will be when we take it on the road but that is an adventure for another day.

I am uploading a short and not very exciting film of it running at the moment and will post a link as soon as I can. Wings and rope hooks next!

Steve   :)

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I like having a long weekend as I get into the swing of it! Sadly, I am back at work but we did have a good day yesterday where the next job was to fit the wings. Dad has painted the brackets so they were loosely fitted.


Then a positioning trial for the wing itself.


Once in the right place, we scribed through the hole from underneath and then took the wing off to drill it.


The wing was refitted with one bolt, the remainding holes were marked and we drilled them all through.


Then to the other side where it became apparent that something had gone wrong with our alignment.


A bit of attention from the press soon sorted that out but the paint will need touching up.



Fronts complete!


Onto the rear where we played the same game.



The full set.



It doesn't look much but it took us all day to do it. Oh well. Another tick in the box.

We are just about ready for the Bovington WW1 day on Wednesday 8th August followed by the road run to Great Dorset Steam Fair on Saturday 11th. We hope to have at least one trial trip before then!

Steve   :)

Edited by Old Bill
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Well, we are getting ready for Bovington next week. One thing we don't have fitted is the horn. Dad found this super example on a well known auction site and fitted a new bulb as the original had perished.


Unfortunately, the rubber is a bit thicker and the ferrule would no longer fit so I have had to spin up a new one. First job was to turn up the chuck.


Then cut and anneal a disc of 20swg brass.


After the first go, it looked like this. I annealed it three more times before it was right down.


A quick polish with a bit of emery.


Bore out a suitable hole.


Looking promising.


And then fitted using washing up liquid as a lubricant.


Now we need a bracket for it!

Dad is keeping busy and has fitted the gas generator bracket down by the driver's right foot. That has filled up two more holes in the chassis.


We have only ever found one original WD gas generator and that is on the Dennis so when I get a moment, I will make up a copy.

The other thing we are aiming to complete before Bovington are the main hood frames. They won't be painted in time but should give us a refuge from the weather if needed. Dad has cut and fitted the centre bow bases to the body. The bows should be structural and permanent but as our shed is too low, we have to make them detachable, hence the stub piece.


The full bow will overlap and be bolted through. The other bows are 2" x 3" angle and need to be bent. That is a bit beyond our capabilities so we have had some quadrants cut and these are to be welded in on completion of the bends.DSCN6162a.jpg.06f83aa3db144388f9062da21865cdc8.jpg




Once the bows are bent and welded, there are brackets to be rivetted in which carry the longitudinal bars and I have been making these up. They need to be 45mm wide but we couldn't get that size steel so first job was to cut along their length to width.


Then a simple case of bending in the press using my jig which is never quite big enough.




Corners filed to a radius and rivet and bolt holes drilled.


Ready for fitting when the time comes.

Steve  :) 


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