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Another J Type on the way !

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We have been experimenting with an electrolytic  rust busting device, which has been showing great promise in early trials.




Made from good solid (free) scaffold boards with a 1000 gauge plastic liner , the tank contains about 12 gallons of water with 6 cups of soda crystals for the electrolyte. Various anodes have been tested and the best was a length of box section steel, this was connected to the positive terminal of the power source. The negative end connects to the job  in this case the steering column and this forms the cathode. 


At first results were disappointing , with a small battery charger struggling to provide 2 amps to the rather cold mix. Stan then produced the heavy artillery, a monster starter charger which soon got the party started and the bubbles flowing. We explored the full range of options which included a flat out setting of 24 volts and 28 amps. This was proper motoring and was restricted to short periods of boost when required. Amongst other beneficial effects this began to raise the water temp and we achieved 24 degrees C which was much better for the reaction.






The results shown here after about 4 hrs show the rust mostly gone and replaced by a black substance which cleans off easily ready for paint. The rust was deposited on the anode which was growing a fine set of  Titannic whiskers. Various modifications are at the planning stage, but initial results are very encouraging. 





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Nearly done, bar a few finishing touches, it only remains to light the wicks for a grand finale. But first, I need to find some paraffin.

It now only remained to strip out the camshafts and the dismantling was done. Almost immediately I hit a familiar problem which Steve also encountered on the Gosling Thorny. The end of the exhaust cam

My decision on the cylinder liner pins has been to leave well alone and allow the chemical assistance to do it's job. This has meant I can focus on the paintwork, which is where I'm on solid ground !

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Presumably about the same as charging a battery, maybe more on the higher settings ? We found the 24 volt input to be the most effective and did most of it on that with the amps on minimum ( 5 or 6 ) . Advantages over acid include faster progress, no damage to bright areas or brass bits and it does not smell like somethings died in there.

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Prep time for rusty bits has improved considerably and we are honing the technique as we gain experience. Good connections to bare metal are important and any loose parts (nuts and bolts etc.) need seperate connections to be included in the process. The brake arm and adjusters were put through the mill and after a light brushing with the rotary whizzer, came up like this.


The hidden adjuster screw threads did put up a fight and most of a day was spent freeing them up, but Bonda Prime was duly applied at last orders and the brake rods will now join the queue for paint.



The previous batch has now had a 2nd top coat of Service Colour.



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I was promoted off the floor today ! Stan has cleared the promised shelf space and I have taken up residence in the stores. Several parts are now ready to be reunited with the chassis, with more on the way. Very satisfactory.


The water jacket connector was cleaned up manually a while back, with good results and has been awaiting one of Stan's free moments to build up the missing corner with braze.



It turns out Stan is a bit of a star on the brazing front as well and a new corner was created freehand after carefully preheating job and firebrick to ensure a nice slow cooling down period.




It only remains for me to file the surface flat and re drill the hole and that's another bit ready for paint.





Edited by Tomo.T
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Nice work with the brazing. I wonder if MIG brazing would work for that sort of application? 

(It wouldn't be better, but not everyone has access to Acetylene, and the access is reducing steadily) 

I would be tempted to skim the sealing face flat on the lathe, it looks easy to hold for that. 

Edited by andypugh
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Looks like you filled in the entire corner with brass. I have done the same job by locating a piece from a similar flange, cut the corner off and matched the two pieces together to a reasonable degree, then brazed them together.

Are these pieces the water passage between the two cylinder castings? 


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Got somewhat diverted this morning with the rugby ! 🤗 but back on the case this afternoon for some filing. Miserable weather and poor light for the pics, these are the best of them.


The mating surface is pitted and not very flat, so will need facing up and a thicker gasket.


Otherwise the braze cleaned up well, I clamped and bolted the other faceplate back to back, to drill the hole, it remains to be seen if that was a good idea or not.




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Due to a lack of work, I have been able to catch up on a bit of painting. (Anyone requiring proper signwriting or brush painting, please get in touch ! )

I found the sump languishing on the shelf and decided to lavish further attention on it. This ugly duckling will soon re emerge swan like and will hopefully repay my efforts by remaining contenent, once filled with oil .Various other parts are also making progress. 





Progress has also occured at the airfield and the project has moved to an independent workshop where I can have free access. This is a major improvement and much appreciated.




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It would be good to see some bits going back on I think. Here is the steering box taking up residence in its new work place. It needed a little persuasion as the holes didnt quite line up, (different parents) but a little file work soon sorted that. However, I am not convinced that the end result is quite vertical and it may need a shim to straighten it up.



The sump has come out nicely. If any one needs one of these, now is the time to scan this one and get a pattern 3D printed. (Just saying.)



I will just include a couple of 'before' pics20190506_121442.thumb.jpg.e7163996d71fb516e242851875e4090c.jpg of the moonscape I started with.



Edited by Tomo.T
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My long awaited valves have arrived from G&S and will be taken directly to  Paynes at Evesham where they are waiting to finish the cylinders and valve guides.



Also back from Rob Foreman ( Mr Solex ) is my MOV 35, newly re jetted and refurbished. This magnificent bronze carb is slightly later than the original, but has many improved features, including butterfly throttle, idle mixture adjustment and a choke. These are also easier to find and a fraction of the price of the early ones. This particular example came from the south of France, where it was previously employed on a vintage Bentley. The enormous main jet it had, would appear to support this assertion.


Edited by Tomo.T
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With work being rather difficult to find recently, coupled with some rather expensive engineering work to pay for, I have found myself plumetting towards the festive season with insufficient funds. I have therefore taken on some highly decorative fairground work, which is outside my normal scope of operations. This has been taking all my attention recently, leaving  little time for project Thornycroft.

However I have now recovered the refurbished cylinder blocks from Paynes, which have been bored and linered to Standard A. (4.5") the valve guides  were sleeved and bored to suit the new valves with seats recut to match. Paynes have also supplied new rings including 1/4" oil scrapers which will be taking up residence in the newly ventilated third grooves.

The following pics show today's progress on the front block.







Edited by Tomo.T
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As can be seen from the pictures, these cylinders look to be in superb condition. However,  nothing is without its problems and in the case of the front set, we do have a small crack to deal with.



At least, it could be a crack. Further investigation is needed here. Incidentally the odd reflection is from an infrared  heat lamp, which I find indispensable for painting in the winter months. 

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More of the same today with the rear set, but this time I found a lot more rust and scale in the internal passages, so first task was to sort this out ( again !) 


The rest was a repeat of yesterday's effort and we now have the 2 sets in primer.



No problems this time and this cylinder block is as perfect as you will find for it's age.

Edited by Tomo.T
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57 minutes ago, Tomo.T said:

At least, it could be a crack. 

It looks a bit odd for a crack. It looks like a casting flaw, but a decidedly odd one. 

Maybe build a clay dam round it and see if a pool of <liquid of your choice that won't interfere with painting> drains away? 

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