Thwaites Alldrive model and engine ID

[skoolboi]

Well I felt a bit of plonker for not looking at the photos properly and it's persisting down outside at the moment. I dropped a line to Thwaites spares department, I have asked them for id in the past. Jack in that department thinks the dumper is likely to be an Alldrive 5000 fitted with a Petter BA2 engine (the 4000 had the PH2). A quick Google and it would seem the engine was more advanced than PH type but somewhat problematic, including being designed without a head gasket. The BA series was dropped when Petter linked with Lister. It would explain the similar way of lockingb down the rocker cover to other Petter models.

This is amazingly helpful! I've had a quick Google of the Petter BA2 and can see it is exactly that engine. Hopefully a bit more searching and I can find some spares and a manual, but this will be much easier now.

Unfortunately I'm stuck working all day but my old man has been making good progress. Managed to free up the stuck piston/cylinder barrel but the starter handle is still not moving and the clutch is solid so we disconnected and removed the gearbox tonight. Hopefully tomorrow he will figure out the issue.

Main thing is he tells me he's enjoying himself! I think he gets fed up of all the electronics in modern vehicles.

[cobbadog]

Good progress, you now know what model the engine is and now to find a manual but they are not always needed unless your not sure where to place a piston or a head. Torque settings I always do from a torque chart for the size and thread pitch of the bolts as it is the same right across the board.
Bad luck about it having a drink of water but with the stuck piston free or out why doesn't the engine turn over? Bearings maybe!
Unbolt the clutch and it will let go and then it can be re used no problems unless the plate shows signs of wear.
Glad your Dad is enjoying playing with your toy, they are fun things to do and are a very simple thing to work on. Good luck with the repair and keep us informed.

[v1230nm]

Keep us informed on progress, it makes interesting reading.

Neil. (v1230nm)

[skoolboi]

So he was able to use a mini flywheel puller to remove the clutch, behind which we found a mouse nest or a squirrels store house as it was full of leafs and nuts. Couldn't entirely work out what was causing the stuck crankshaft but after a bit of a clean up things started moving again.
The clutch has had it so will need a new one of these. The stuck piston is now moving through the cylinder barrel (almost) but not nicely so we are looking to get these rebored. Trying to estimate all the costs at the moment to understand whether it will be worthwhile or not; fingers crossed it is.
I'll try to keep this post updated as we go, nothing more frustrating than finding an old post the tackles the same problems you're having but hasn't been updated with the solution.

[cobbadog]

I am not a qualified mechanic but all you need to do is to buy a small hone and clean up the bore with that and fit a new set of rings. Your bore may have what is called the Listard treatment so unless damaged wont need boring. I have done this on so many vintage stationary engines I have lost count and all of them run exceptionally well and it certainly will be good enough to put it back to work full time with no worries. Obviously a new clutch is required along with a new thrust bearing and put it all back together.
Hope it all goes to plan for you.
Cobba