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Another J Type on the way !


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10 minutes ago, Tomo.T said:

I need to find some old style gaskets for these which I hope will take up any slight discrepancies. The originals were asbestos, with thin brass foil each side, so I need to find  suitable replacements, in more socially acceptable material. Anyone have any suggestions please  ?

Try E Dobson &Co., Keighley. 

They made the copper non-asbestos gaskets for my Karrier (and numerous other projects).

Just send them an old gasket to copy (in a self-sealing polythene bag) or knock out a paper template.

Quick turnaround and very reasonable on price (or at least I thought so).


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Posted (edited)

Here are some further hi def pics from Stan.

The spark plug towers are the originals,  except one, which was replaced by Mike Lewendon. The three originals were cleaned up by hand and young Ben Lewendon took on the locking rings and made a good job of them ! Cheers Ben.


The exhaust valve caps are beyond repair and Mike is on the case with some replacements.

Oil level gauge and breather are back on.


Plus Rosso's oil pressure regulator. Looking good Dave !         T.B.C.



Edited by Tomo.T
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Posted (edited)

The oil pump has been reinstated after a last minute rescue by Mike and Stan. I won't go into details, it is far too distressing. Suffice to say it is back in place and working well.


Also fitted up the primer tank for extra bling.


The mag platform appears to support only the outer fixing holes, which I find rather odd, but it must have worked ok like that ?



Next step is to get the sump and timing cover fitted , which will require some more nuts and bolts, usable originals are running low. Also have been running on vapour financially and need to get some work underway, so progress is at a halt for the moment.










Edited by Tomo.T
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Thanks guys, I have one already which is much the same, and even has Thornycroft  on it, but they are both next generation items and not quite right for a J.  Having said that, I will probably use it unless I find a proper one.

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Posted (edited)

The opportunity was grasped to fit the mighty Simms.( Pics by Shaun.)


Regular readers may remember this magneto came with the engine from Australia and was paired up with the lucky find of an impulse coupling or 'clicker'.


This clever bit of kit holds the mag still against a spring whilst the engine is turned, then releases it just before ignition is due. The armature then spins round creating a much bigger spark than would otherwise occur, with the feeble efforts of the decrepit old fool on the starting handle. 


The SR4 X is really a product of the late 20's, but has the benefit of progress in development, and it fits ! However, some work will have to be done to match up the drive  couplings, which don't. The mag had a thorough strip down and clean and is now a 'belter' in every sense of the word, producing a big fat blue spark at the slightest provocation.

Edited by Tomo.T
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Nice looking magneto there, Tomo.  And the SR4X seems to be a pretty popular on ebay.

Yours seems to have good caps also.  I want to get mine sorted soon as I believe there is a quite a wait on getting them serviced/repaired.  Out of interest, did it come with the caps, or did you have to source them separately?

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Thanks Dave, I had to source a cap, mine (typically) had a broken tower. I picked up two on eBay, one of which fitted !

Incidentally they clean up best with an application of brown boot polish !

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  • 1 month later...

There has been a fair bit of progress behind the scenes in the last month. Mike Lewendon has been keeping the CNC busy and has produced a lovely batch of top covers for the exhaust valves. 




These are now fitted in their respective pockets, after a bit of a struggle!  It remains to sort out some reduced head locking bolts to finish the job.


Mike also milled out a top cap for the steering arm ball joint, which is the missing link in the steering 'chain' and should mean functioning steering once fitted. Another milestone.




I mentioned to Rosso in Australia that I was short of an oil pipe connector for the pump and he must have turned one up straight away, as it arrived on my doorstep in record time all the way from Oz ! 


Rosso also spotted a correct Simms magneto drive gear, which will replace the repro version I had. He also kindly sent this and I have spent some time on it already.


Unfortunately the locking/ adjusting screw had more or less rotted away, but I had a replacement from the original........ which sadly didn't fit !  Engineering will be necessary!





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Further excitement arrived in the form of manifold gaskets from Dobsons (as recommended by Doc.)



They are beautiful copies of the originals with a modern graphite /glass fibre filling to replace the dreaded asbestos.



They were fitted and manifolds fastened, we will have to wait to see if they have successfully taken up the slight irregularities.

The sump had broken out in a rash of blisters during its time in storage, maybe due to the variety of chemicals involved in its restoration.  More rubbing down, filler and paint later, the sump is now ready to fit.












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  • 1 month later...

Dunc has been keeping me busy of late, so there is not much to report on the J type,  however work did commence on the ht tube before I left. This is an unlikely survivor, although the Oz climate has been kind to it, other problems were apparent. The poor old thing had been subjected to a a good beating with a blunt instrument at some time in its past life. This had left a number of 'dinks' in the tubing and bent one of the cast brass brackets out of shape. 


I first tackled the 'dinks'  by inserting a suitably sized lucky off cut into the tube end and tapping it gently through. It was not possible to anneal the tube due to the soldered joint but luckily for me the tube was very soft and went back to its previous shape with no problems.



Flushed with success, I then approached Stan about straightening the bent brass arm, which he was reluctant to attempt as it would probably break. He did give it a go, after annealing it twice, but he was right and it did crack, so he silver soldered the bits together and it's now very hard to see the join. Excellent work from Stan.


A little more paint followed and that's another original bit saved for further service.


Elsewhere, the oil filter tube had another clean by Stewart and is awaiting its plug, before the sump can be fitted and nutted up.



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Mike kindly turned up the missing plug while I waited and suddenly we were clear to fit the sump. I had recently obtained some old stock automotive 3/8" Whit nuts from Australia  and these were put to good use along with slightly less authentic locking washers.




The engine has grown considerably with this latest addition and is now sealed apart from the locking bolts for the exhaust valves, the timing covers and the priming cocks.... oh, and the mag drive shaft which is making progress. 





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On 7/6/2021 at 11:00 AM, Tomo.T said:

Mike kindly turned up the missing plug


Hi Tomo.

It is all looking very smart now! Did Mike include the plug extension to block the hole in the end of the suction tube and give it some support?


Easy to miss if you don't know!

Steve 🙂

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The mag drive pinion from 'Rosso' in NSW. was not quite the direct replacement I had hoped for. In fact, it rapidly turned into a full scale engineering project of its own !


Mike Lewendon took up the challenge and first bored and bushed the body, extending the collar to cover the annular thread on the shaft. The clamp bolt was smaller and thus out of kilter with the annular thread which it needed to engage with to provide infinite fine adjustment to the timing. ( A very useful feature ! )

Mike made a solid bronze plug for the hole and all was expertly silver soldered together by Stan.


Mike, meanwhile, worked out the correct centre and then drilled a new hole for the clamp / adjuster bolt, which fitted perfectly.




The shaft was carefully shortened in order to accommodate  the impulse coupling and Stan's welding produced an invisible repair.


The shaft was then re re-aquainted with all it's drive gear, bushes and ( new ) bearings, re assembled into the timing chest and connected up to the mag. All fitted nicely, but the mag needs raising slightly which will be accomplished by a spacer plate underneath.




Thanks are due to Mike and Stan for engineering excellence and to Rosso for finding and sending the parts. 

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Stan has sent some hi -def pics of the finished mag shaft.



I managed to find the spacer plate that came with the mag and adjusted the foot plate to suit, so it's all lined up and ready to go.



Obviously we could have attached the brass pinion directly to the shaft and adjusted the timing with the vernier coupling, but we went the extra mile and utilized the annular thread, which was the original means of adjustment. The result is a satisfactory compromise,  which  gives us the best of both systems and allows the use of the impulse coupling to provide easier starting.


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  • 1 month later...
Posted (edited)

Meanwhile back at the airfield....

An earlier attempt to fit the foot pedal shaft and connect up the steering, ended in abject failure, due to a missing end cap in the case of the steering gear, and a complete refusal to fit by the pedal shaft. I returned to base defeated, to ponder the problems.

It turned out I had assembled the pedal shaft components incorrectly, so that was an easy fix. The missing end cap was machined from solid by Mike Lewenden on the CNC mill. (see previous posts.)

Armed with these improvements,  I returned to the fray, and this time everything fitted correctly, to my considerable relief. 






I treated myself to a short spell in the driving settle, watching the front wheels turning under the control of the new steering wheel. Not too much mind, as such practices are specifically forbidden in the drivers manual !




Elsewhere, the reduced head bolts for the exhaust caps have been turned out by Mike and fitted in their respective holes.



The rest of my time recently has been taken up with work projects, which has to be a priority at the moment.






Edited by Tomo.T
Photo balls up.
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  • 3 weeks later...

Attention has been focused back on the cylinder head where the locking tabs for the valve cap rings needed tackling. On examination it was difficult to see how these items were expected to work. Mike Lewendon  suggested stepping the ends underneath the tabs on the valve cap rings, thus improving the grip. Also a slight straight edge was taken off the otherwise curved tabs. This led to a two day filing and fitting exercise  which has now produced the desired result



The fixings are temporary and will be replaced with the correct bolts as soon as EBay has provided


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A visit to Quainton for the Classic car show on bank holiday Monday was a good excuse to meet up with Steve and Tony Gosling, who had kindly brought some patterns for me to borrow.

The three Musketeers had driven over in a convoy of WW1 lorries. The Halley of Barry Wetherhead, the Goslings J type and Graham's AEC, all arrived  on time and made a fine sight, which I completely failed to capture on camera, (Anyone have pics of this pls.)      Steve was deservedly awarded the best of show cup by the judges.


I returned to the workshop to examine my borrowed treasure. The first step was obvious and some minor repairs were carried out to the patterns, followed swiftly by a fresh coat of Bonda. So I am on safe ground at the moment, but I fear it's not going to last.





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The water pump casing patterns  (or prize turnips ) are coming on nicely. They were treated to a spin on the mighty Colchester to sand up the outer surfaces.



A little filler was applied, followed by several coats of Bonda. This has produced a gradually  improving surface with every flatting and if all else fails I shall have a lovely collection of table lamp bases.



Next up is to cut the core pattern in half, which will be a delicate process for sure !


I have been warned to expect another package of goodies from 'Rosso' in Australia.  I am eager to see what has been achieved despite the lockdown in NSW. I will post pics on arrival.

Edited by Tomo.T
Too many treats.
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  • 2 weeks later...

The promised package of desirable goodies arrived today, all the way from Australia. 'Rosso' Rossington has been busy again and has produced some stunning items for Madam Thornycroft's jewelry box.



First up is a fine set of primer cocks, in the English style. These prominent items sit in a line above the cylinders and were intended to provide a means to prime the engine for starting. In these days of high octane petrol they are no longer necessary and are purely decorative in their current form. I am tempted to drill them through to make them operate though?



Also included was a simplified copy of a No. 4 Rotherhams grease cup as fitted to the king pins on J types. I have failed to find an original, despite four years looking. All this one needs is a knurled edge, the Rotherhams lettering and some grease !




Brilliant effort Dave, thank you very much.

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