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Great War truck

WW1 Thornycroft restoration

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11 minutes ago, Old Bill said:

I have some film files to post once I have worked out how to do them.

YouTube is probably easiest. 

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during dinner this evening, I will raise a glass and toast your gang!

 

John G

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Quote

I have some film files to post once I have worked out how to do them

 

I am ready!

popcorn.gif

Edited by rog8811

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A great achievement. Well done to you all. Now to the next major task of the road test, to see how well everything  else blends together.

 Doug W

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There's no other feeling quite like the one you get when an engine you have built rumbles into life.  A great achievement, gents. We stand in awe.  Next stop Brighton, then

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6 hours ago, Old Bill said:

I have some film files to post once I have worked out how to do them

I have just realised why the delay. The films must have been Super 8 and have been sent away to be processed......

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57 minutes ago, Asciidv said:

I have just realised why the delay. The films must have been Super 8 and have been sent away to be processed......

Nope, not super 8. They need the orchestra to play the music for their moving pictures

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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 engine back together ready for another go. Moving the camshaft had messed up the ignition timing so I adjusted that, primed the cylinders and had a swing.

There was a definite 'chuff' but it sounded as if it had blown straight through the exhaust. I checked the timing again and realised that was set to the wrong cylinder so adjusted again and had another go.

This time, it fired twice and rotated the engine but did not pick up and run. Now, this lorry has no choke and the instruction in the manual is to hold the float down until it floods and then start. This didn't seem very satisfactory to me so I quickly made up a choke for Father to hold against the inlet.

DSCN5517.JPG.72d7bfbac2cee1ae238374120c47ef20.JPG

I instructed him to keep the hole in line with the inlet!

I had another swing and away it went. Unfortunately, our guest photographer missed the actual start! The film starts a couple of seconds later.

We ran for several minutes until it was all beginning to warm up and the exhaust paint cooked itself on. It idled very nicely but as soon as I tried to open the throttle started to die until I released it. I tried this several times until, in the end, it stopped. Now that it was warm, it was too stiff for me to swing so we left it at that for the day and called it a success.

I have since stripped the carburettor down to see if there was any dirt in the main jet passages but there was nothing obvious. The jets are the sizes published in the manual so I am puzzled and open to suggestions please. It is a 35mm Solex.

Many thanks for all of your kind comments. We are a bit closer to our objectives but not there yet! We will have another go tomorrow when my arm has recovered!

Steve  :)

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Congratulations to all! Great to see and hear it running.

Does the magneto have impulse fitted (I don't remember if this was mentioned previously)? We have a couple of tractors fitted with impulse magnetos, and for starting require just one pull over compression, very much easier than having to turn it over many times, and less likely to cause injury.

Hope you sort out the lack of throttle response. Again, we have a similar problem with our 1932 Leyland Cub, and after extensive tests checking timing, vacuum, compression pressures and carbie cleanout, still have not nailed it down. We are going to fit a new set of spark plugs as a last resort, not that this is likely to be your problem. Ours has been running for a number of years on the existing plugs, and they are sooted up somewhat.

Ian

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I had the same kind of problem on my 1925 citroen, it started and idled well but as you thouched the accellerator it died off. Here it turned out that the markings on the flywheel were completely wrong. So instead of 7 degrees pre igniton it was 12 degrees late...

Nice to the beast running after such a long time. :thumbsup:

Edited by Citroman

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Steve

Congratulations on the first start-up!!!. 

Had a similar problem on my 1904 De Dion Bouton. Also ran a Solex on first start-up. Engine would only idle for 3 minutes and then quit. Would not rev up. Changed the plug, rebuilt the carb again, reset ignition timing. No difference. Decided to recheck valve timing. I had assembled according to factory marks during the rebuilt. I now worked on basic Otto principles and came to the conclusion that the timing was out by one tooth. Assembled the valve timing one tooth advanced and all was well.

Good luck!

Regards

Tom

05052017.jpg.be6c5b885c1b2da32ee1aad354e9a347.jpg

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I’ve been following your progress for quite some time and find great pleasure viewing each of your postings. Having no engineering or mechanical skills myself, I have total admiration for yours and great respect for your wonderful attention to detail. I also find it fascinating that via this thread you can receive help and advice from people (with the necessary skills) from all around the world.

Many congratulations to all of you for your progress with this magnificent  restoration.

Trev

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9 hours ago, Old Bill said:

Now that it was warm, it was too stiff for me to swing so we left it at that for the day and called it a success

With it being too stiff to swing when it is warm, does this mean that the engine would have been left running all day when in war service?

 

8 hours ago, k2lofty said:

Superb, although I did feel for you on the handle.

 

I was waiting for Steve to be given oxygen. 

 

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Hi Chaps.

Many thanks for all of your comments and encouragement. I think I have some serious checking of timing and set -up to do. We did swap the crank gear from one crank to the other as it was in much better condition and it could easily be a tooth round. I did work out where I wanted the valves to open and then found that the marks lined up which pleased me at the time. I could be wrong though as it is all a bit difficult to check! I do hope I haven't got to pull the camshafts again but we shall see.

Cranking the thing is certainly a feat of strength for which my desk-jockeying is not good training. An impulse starter is in the plan but I just haven't had a chance to do it yet. Oxygen sounds like a good idea. At the moment, I settle for having only a very light breakfast as I don't want to see it twice!

The engine stiffening up is curious as it doesn't do that on the other lorries. Barry Weatherhead has reported the same issue with his Hallford lorry. The Thorny has had new pistons, rings and liners which is more than we have done on the others so that may be the issue. I hope it doesn't seize completely on a long run.

Lots of food for thought. Now back into the fray!

Steve   :)

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10 hours ago, Old Bill said:

since stripped the carburettor down to see if there was any dirt in the main jet passages but there was nothing obvious. The jets are the sizes published in the manual so I am puzzled and open to suggestions please.

Wild speculation, but as you no longer have the long tube from the exhaust manifold to the carburettor perhaps there is less depression in the choke tube. Does it rev at all (or die differently) if you apply the throttle with the choke-board in place? 

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10 hours ago, Old Bill said:

I have since stripped the carburettor down to see if there was any dirt in the main jet passages but there was nothing obvious. The jets are the sizes published in the manual so I am puzzled and open to suggestions please. 

For what it is worth, my gut feeling is fuel starvation. Could the problem be something as simple as incorrect float level? You mention that there is a way to hold the float down; I would suggest holding it down slightly until the engine note changes as the mixture richens, then begin to open the throttle. 

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1 hour ago, Old Bill said:

Cranking the thing is certainly a feat of strength for which my desk-jockeying is not good training. An impulse starter is in the plan but I just haven't had a chance to do it yet.

I am a bit surprised that Thornycroft expected anyone to do that. Our Dennis (admittedly a bigger engine) is impossible to crank all the way round and there is a trembler-coil second ignition system. So you pull it over TDC a couple of times and then turn on the trembler coil, hopefully kicking the engine round fast enough to bring the magneto in to play. 

I thought that was standard for the time. 

As for the engine getting stiff when hot, that does leave me wondering about the piston ring end gaps. But I seem to recall that you set those? 

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Steve

I had a similar problem on one of my Austin 7's. choking the carb with my hand would let it rev better. Choking the carb by hand allowed you to sort the mixture to the availible fuel and it would rev to a degree

Essentially opening the throttle leaned it out, so it wouldn't run. and conked out. Just as your engine is doing.

Unfortunately after much scratching my head there was two issues. One was a fuel starvation issue. Rubber hose braking up. blocking the needle valve. also partially blocking the jets

The other was that the auto advance was not, this was solved by giving it a load after starting and going for a drive.

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That warm air feed from the heat shield must have been fitted for a reason. Have you discounted possible carb icing as a reason for the issue? 

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