thornycroft Q bb/4

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 https://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

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

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

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

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

For gaskets try these guys.

I've used them in the past and they're very good.

Located in Hornsby in Sydney's north.

http://www.swansonsgaskets.com.au/setup.htm

Gudday Brockwood... have you made any progress?? Robert

 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 

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 

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

David

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.

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.

Hi have  been doing a bit just got reverse  gear back  now to see if it works 

Hi all bit of an up date had  been out of action for a couple  of years now  had both knees  replaced . After checking new gear would work the box was striped down to get all the rust out .and there it sat now done and back in sub frame a mate made a new drain plug which   was missing its the same as the diff .   many years ago i was given a bb4 engined j model manual which is very helpful the attached was in the back of it i thought it may be of interest    b

Good to see you back and looking forward to further updates!

Steve   🙂

Good to see the progress.

Is there a serial number on a brass plate on the engine and also a stamped number on the left front end of the chassis. That would allow  a date of manufacture to be gained.

 Not many Q models about, I found the rear axle of one here in N.Z. and a front axle at another location. 

 The rear axle is so different to the J  having raised sections as overriders about the springs.

 Doug 

Hi i believe its bb4190 could never find the chassis no must have another look  b

Some searching has found BB4 190 as fitted to Q chassis no. 10910 leaving the factory on 30-8-1924

However the engine may not be the original as things got swapped about over a vehicles life. 

hope this helps

 Doug 

Great to see you back at this interesting project! 😁

Alec.

Been working on engine  gesrbox and reconecting  thougt i had better befor i forgot were bits went got some pics. Found some nos on block

Where were these numbers stamped? Can you show a photo of the location.

I have found similar stamping on a gearbox and take them for the initials of the assembler or foreman  doing the work. 

 Doug

They run from the rear right block to crankcase flange to about the mid point

Hi all  been back at it started with gear box and worked forard . Now onto engine looking back it was 2015 18 when i was last at it and one forgets i thought the motot was good enough it would run . however it needs the block pining a valve seat and four sleaves of as much concearn is the fact that its been runing without the oil pump suction filter refure pic . There was 10lt of mud higher than the picup with 15lt of  oil on top so pulling  sump to chech oil system and pull no 3 to see whats going on there . the engine is booked in with the local old school recondioner whos done simmiler work  for me befor on a fordson f engine

Hi all been held up by this bolt  i what to get rust out of the spring it looks to unscrew after lock nut and locking saddel are removed  i have had some heat and a  10 foot handal but no luck i wonder if it ruduces from 1 1/4to 1/2 and goes right through spring to locatet it ?