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brockwood

thornycroft Q bb/4

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Hi found the truck in 77 recovered it with uncle had been from new a mobile stone crushing plant so no cab.  Didn’t really know what we had pre computer age has a winch on right rear wheel so thought military or colonial special based.  was is missing carb, mag, oil line to timing cover, bonnet, alloy trim, fuel tank, rev gear, uncle moved away and project was in limbo till now. We have unseized the motor. Today got the clutch released and working on freeing up the gearbox and transmission brake.  Found some old pics from 77 and a link to some vids . when the chassis was shot a few years ago we didn’t know what we had we now know its basically an enlarged j model with a  larger engine rated at 50hp but actually over 60 but it apparently dropped valves so was short lived   it’s an f head  the follow ons I think went back to side valve.  I am lucky enough to have a late j model owner’s manual with the same engine which is a help img032.jpghttps://i.ytimg.com/vi_webp/6w8uODrNcBg/mqdefault.webp https://i.ytimg.com/vi_webp/ZVMYwU-UN3A/mqdefault.webp https://i.ytimg.com/vi_webp/rRBarmXh26k/mqdefault.webp https://i.ytimg.com/vi/EUpHx3CDvas/mqdefault.jpg mucked up link go here https://www.youtube.com/user/edgiee27/videos?view=0&shelf_id=0&sort=ddand look around

Edited by brockwood
more imfo

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Interesting to view your videos of working on the engine. Please keep us advised of progress. Is there a chassis number stamped on the left front chassis dumb iron?

Also any stamped marks about the king pins. I've been trying to relate these stamped numbers to production or series numbers to help date stray axles.

Doug

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th 5.jpg update Pics 1 factory motor 2 unseized roller followers 3 freed clutch and brake 4 follower mount new valve cover

 

the motor clearly had been working with out valve covers all freed up and exhaust valves ground b

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Edited by brockwood

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now have rear head temporally back on have ground intake valves and freed up helmet [had been open to weather] had to extract broken Hemet stud and broken off spark plugs does any one know the right plugs and the best thing to use as wicks for the overhead valve oilers also a supplier of head studs and remade head gaskets in aus thanks b

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I really enjoyed watching your videos re the Thorny engine and chassis. The commentary is a big change from the odd word attached to the odd photo... as is the norm here. You have inspired me to have a go at this form of communication. Robert

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 Hi have been doing a little we managed to source a radiator thats copy quality the old one got mislaid. on inspection of the stuck gearbox which we knew had no reverse we found it had no plug in it was dry and had a rats nest in it. So after a rinse it was filled with oil and left to soak a few days latter we put a spanner on the top shaft and with gentle rocking after an afternoon it came free. It’s now off getting a new gear cut. The gear appears quite fragile over the drive key after allowing for the depth of teeth refers to pics there is not a lot left. the reverse idler the loose gear and shaft in pics   is constant mesh and had sized we suspect causing the breakage it had wiped out bearing material that had splayed out and  jammed it on the case it took quite a lot of getting out 

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Very like the J in style. Our reverse gear idler bearing was completely worn away as well. I find this odd as there is no load on it for most of the time but the bushes typically disappear.

Good to see you making progress!

Steve  :)

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Could be caused by people putting EP90 oil in there. It eats bronze / brass even without a load.

David

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Posted (edited)

It depends on the type of Sulphur used in the oil, as one type (active Sulphur) reacts with the copper and brass in the bushes and worm wheel. At higher temperatures the reaction is greater.

Edited by john1950
correction

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Good to see your progress. I came upon some notes I made concerning these vehicles. There were Q types in military service in the Great War, they had an increased payload of 5 tons, but they all had the 40 bhp M4 engine, as fitted to the J type. BB4's became available from 1924 rated at 50 bhp. I dont know if they were ever taken up by the military.

Good luck with the restoration.

Tomo.

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