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Another J Type on the way !


Tomo.T

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Having gathered together sufficient parts to make a start over the last year, I am at last ready to commence the restoration of Thornycroft  J type No. 2393 of 1915. This chassis was recovered from beneath an old chalet in Skegness  and thus protected has survived in remarkably good order. It was discovered and recovered by Graham Hand and passed on to John Marshall, who began to  add parts as they became available, but was concentrating on his front runner J type 2282 also of 1915.

It is great to find a chassis, particularly one in good condition, but the icing on the cake would be an engine and I became aware of the existence of a collection of Thornycroft parts in Sydney Australia. These parts from various models had been rescued from an auction having failed to attract any bidders and I soon discovered the new owner, Ian Browning was willing to move them on, providing I took on the whole collection. This was more than I wanted, but I decided to go for it and with the blessing of the Australian Government, I made arrangements to export a container load of rusty metal from the other side of the world. Ian took on the job of packing and loading in temperatures of 40 degrees which can't have been pleasant ( Thanks mate !) and after a 3 month voyage I took delivery at Southampton.

The haul included 2 chassis (one 'X' one 'J') two M4 engines, one fairly complete, the other less so and various other hard to find parts. The chassis were just post war with no numbers visible. After a hard life hauling loads on Australian roads they were put to work again as farm trailers and further abused until abandoned and rescued for preservation.

I had little interest in the rare X type parts,( being a lighter weight export model) and after considerable wrangling managed to swap these and the tired J chassis for the current 1915 project. I now have temporary accommodation which is secure if a little draughty on the Ox/ Bucks border. Anyone with workshop space in this area and/or an interest in helping with this project please shout ! I am also seeking parts including a gearbox, water pump and Diff gear.

Regards,

Tomo

 

 

 

 

 

 

 

 

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  • 2 weeks later...

Here's a pic of the inlet side of this M4 engine which shows some interesting features. Although it was supplied after the war it still has the early type oil pump with a priming tank and a cast iron inlet manifold. ( Most being cast in aluminium at this stage.) This perhaps infers the using up of older parts post war. The radiator however is a later design and  is mounted lower in the chassis which will make it and the header pipe redundant for 2393.

The engine appears to be pretty sound, but needs to be in a better environment before stripping down and examining it's internal state. Some movement on this is expected soon.

the chassis is back to it's underpants, awaiting the tender attentions of a Blaster Man and some rapid paintwork before winter gets stuck in.

Tomo

 

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  • 1 month later...

With the help of Shaun ( Prague1996 ) I now have all my eggs in one basket and the engine and parts are eyeing up their new chassis. A very successful mission albeit requiring some improvised unloading techniques, and a rather late finish !

The chassis has had some attention prior to blasting, having suffered butchery in the past in order to accommodate a wooden hut. There were also several cracks to repair and I have used up a lot of favours from my old mate Stan Lewenden, Welding  Wizard and Ace Fabricator. The following pics will hopefully illustrate progress, but I apologise in advance for the quality as they were all taken in poor light on my phone.

 

 

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The most delicate operation involved the front chassis member where a nasty crack had appeared right through the treasured  chassis no. and down the side causing the complete separation of the end of the plate. This part is not under stress and is held by the front bolt, and the later added internal reinforcing piece, so we decided to weld the outside only to preserve the number. Note the three figure engine No. from 1915.( lovely !)

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As you say, this part of the chassis should not be under great stress, particularly if the bolts / rivets have not been loose. However the Goslings' J was cracked in almost the same place. I wonder if it could be a result of weakness caused by the manufacturing process ? And why only the LH chassis rail ?

David

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I couldn't resist poking about on the engine and the oil pump was soon removed for inspection. It was choked with red dust and I took it home for a more intimate examination. 

I have previously read that these pumps were die cast aluminium, but this one is very definitely a heavily tinned and leaded gunmetal and the gear shafts run directly in this with no bushes. Having said this, the wear is now such that bushes will be a necessity before any more pumping occurs. There is also considerable wear on the drive pin which is pretty standard for the V2 pump I believe.

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44 minutes ago, David Herbert said:

As you say, this part of the chassis should not be under great stress, particularly if the bolts / rivets have not been loose. However the Goslings' J was cracked in almost the same place. I wonder if it could be a result of weakness caused by the manufacturing process ? And why only the LH chassis rail ?

David

Hello David,

Yes, I understand this was a recognised fault on J types and a specially extended internal reinforcing piece was developed along with tubular supports for the bolts. I have one of each type of support, the offside being unaltered, but it also had a small crack, now welded.

Tomo

Edited by Tomo.T
clarity ?
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As David pointed out above, cracked front chassis members were not uncommon on J types. So was this due to a manufacturing fault, a material failure, or was it simply due to stress from vibration of the solid mounted engine ?

Construction or use? Any metallurgists in the house ?

Tomo 

Edited by Tomo.T
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I have consulted "Auriga" on the subject and he seems to indicate problems with the early arrangements.

Book of the Thornycroft  p66

In earlier vehicles with short dumb irons, we frequently found it necessary to replace the two through rivets by bolts, with tubular distance pieces between the frame flanges, thus enabling them to be screwed up hard. In later vehicles an improved pattern of long dumb iron was fitted by the makers and this gave no trouble.

Many horses pass this way !

Tomo

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  • 3 weeks later...
On 12/19/2018 at 11:14 PM, David Herbert said:

As you say, this part of the chassis should not be under great stress, particularly if the bolts / rivets have not been loose. However the Goslings' J was cracked in almost the same place. I wonder if it could be a result of weakness caused by the manufacturing process ?

It looks like a weakness caused by the number 9!

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It's always interesting to read contemporary accounts.  Lt Col G E Badcock (A history of the transport services of the Egyptian Expeditionary Force 1916-1918) simply says (p.249): Anti-Aircraft Section used Thornycroft lorries to a small extent, but so few were employed that it is impossible to criticise this vehicle.

However, Lt Col F W Leland (With the MT in Mesopotamia) says (p.113): There were several Anti-Aircraft sections and 'Caterpillar' companies which also took part in this advance to Baghdad.  The 'Caterpillars', however, were unable to move owing to the fact that no bridges were able to carry their weight at the time, and they were eventually brought up by river.  The Anti-Aircraft sections, notwithstanding the extraordinary heavy going over deep sand, managed to get through to the Dialah by dint of pushing and towing, etc.  Most of them suffered a fair amount of damage, the dumb-iron and Carden shafts being a source of trouble.  With regard to the frame, it was considered that the position of the towing hook was too low down, and these were afterwards placed at the bend of the dumb-iron, in a straight line with the rest of the frame.

And then later (p.183): THORNYCROFT ANTI-AIRAFT GUN LORRIES: The front towing hooks of these were altered and placed higher up just on the bend of the dumb-iron, so that a straight pull could be obtained instead of the original position, which was inclined to have a lifting action.  This was found necessary in view of the number of dumb-irons which were smashed in towing these heavy vehicles over almost impassable stretches of desert.

 So perhaps the fracture is a result of towing?

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Interesting thought Sir, the tow hooks are clearly not in line as constructed. However, I have not yet seen any evidence, photographic or otherwise of the movement of these  hooks in service and it could be that the longer replacement dumb irons from Thornycroft cured the problem, together with the replacement bolts and tubular supports mentioned above.

  These tow hooks were a universal fitting on subsidy vehicles and all makes had them in the same position, without it seems, suffering similar problems to the same degree.  I wonder if some of the early chassis may have been formed too cold, setting up stresses, which later turned into cracks, with the horrendous conditions of service they had to endure ?

What ever the cause, we have found the metal welds very nicely and following the recent acquisition of a (near) set of the correct style Government stamps, it will now be possible, I hope, to solve the problem. 

Tomo.

I am reminded that there is a problem with towing these vehicles due to the worm drive diff. and that half shafts should always be removed before doing so.

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2 hours ago, Tomo.T said:

 These tow hooks were a universal fitting on subsidy vehicles and all makes had them in the same position, without it seems, suffering similar problems to the same degree.  I wonder if some of the early chassis may have been formed too cold, setting up stresses, which later turned into cracks, with the horrendous conditions of service they had to endure ?

I totally agree. I can see that towing could rip the dumb irons out of the chassis but the TOP flange of the chassis would be in compression, not tension and there seems not to have been any movement of the dumb iron within the chassis or loosening of the bolts. I think that this is fatigue cracking due to normal driving stresses and cold forming.

David

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Cracking of the chassis about the dumb irons is something I have not seen on any chassis in New Zealand. The nature of many colonial roars was tough going, with long stretches of mud and bog holes in wet weather. Chain and ropes about the wheels seem to be standard for rural work. With vehicles being towed out from muddy conditions one would expect to see damage as a result.

 

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  • 2 weeks later...

Progress being made despite the weather ! Looks like the back wheels have not been off for a while !  Kez made a nice find of a second chassis number stamped on the outer nearside chassis rail. It is the same as on the dumb iron;    CHASSIS N 2393.     Coming on lovely.

 

 

 

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Edited by Tomo.T
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  • 2 weeks later...

Now back after a thorough session at A & C Soda blasters and it's time to get stuck in. First task was to remove the front axle which has been reversed since the chassis was 'trailerized'. The opportunity then presented itself to remove the front springs and strip down to clean up the leaves. The offside spring is original Thornycroft with cut down replacement leaves fitted presumably during field service repairs in France. This spring came apart readily and was cleaned up and greased between the leaves. The nearside one is a later replacement and bears a makers stamp WS & S and a date of 1926. This is interesting and would seem to indicate further road work before taking up duties as a caravan chassis. Although not blown out with rust, this spring was completely frozen and each leaf required individual attention after drilling out the centre pin in small bites. All shackle pins had suffered badly from lubricant starvation and will need replacement. Just one original grease cap has survived. The axle bears a cast mark KF for Kirkstal Forge in Leeds and is also stamped M (for military? )

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Now with a clean chassis can yo check for any numbers and letters stamped about the top of the King pins.  I have been recording these and trying to relate the sequence of stampings to chassis numbers and years.  The idea being to assist in dating individual front axles that survived as trailers.

 Doug

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