The Craftmans Shop > New from Old
Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
awemawson:
As you can see it took about two turns to set it at the spill point, which was a very definite setting - I went past and approached it again several times to get it 'spot on' and I can see why they suggest the use of the swan neck rather than just letting it spill over the top of the fitting. It slows to a series of drips which then can be tweaked to no drip.
I then put the one way valve back in the pump, reconnected the injector pipe, and thought it wise at this point to prime fuel though. Stupidly I just flicked the starter motor to spin the engine and there was an almighty BANG and bits flew in all directions :bugeye:
Looking at the poor old pump it had disintegrated - blowing itself off it's mounting flange. At this stage I don't know if perhaps the one way valve mis-seated and it hydraulically destroyed itself. Or if perhaps having raised the tappet two turns the pump piston contacted the top of it's cylinder and mechanically broke it. I'll certainly need to find out before another pump goes on :scratch:
I have to say that as I was doing the 'rack synchronisation' settings earlier I'd thought that the whole pump / rack set up was rather worn and sloppy, so perhaps this is a blessing in disguise.
Anyway I've dug deep into my pockets and ordered up a pair of injector pumps, so play is suspended until they arrive (so are most other activities like food and drink as they were not cheap :bang:)
RotarySMP:
Well illustrated report thanks Andrew. Shame that the injector pump has left us. Maybe it is the sort of building site machinery which really prefers never to get maintenance :)
Mark
Manxmodder:
I guess that if it's mechanical destruction and the plunger piston has made contact with something then there will be some marks internally to evidence that.
Does your flywheel bear two sets of timing marks? On some of the Petters I,ve seen in the past there is a second set of marks duplicated on the other side of TDC.
These other timing marks are for a counter rotating engine build spec......OZ.
awemawson:
I think most Petter flywheel have the marks on each side of TDC as depending how they are assembled they can run clockwise or anticlockwise (with the right internals) No real witness marks evident showing mechanical contact. The body of the pumps are cast aluminium so they've been replaced before probably. I think Petter had later bits made in India.
Spent the afternoon drawing up gaskets in Autocad for the side covers. Could have tapped them out but access isn't ideal and the Laser Cutter makes such a neat job of things - far better than scissors or knife :clap:
(Did I say - I LOVE my laser cutter :ddb: )
petertheterrible:
Excelent post. Only things I would like to add, watch out for 'over spilling'.
Only thing the PH manual does not state is, in setting spill timing before tightening the follower setting screw is to turn engine by hand, preferably not with the crank but just the flywheel. (Stated in manuals like that of the SR strangely)
Each pump must be checked for 'overspill', if not you will destroy the pump on the PH. (Experience gained the costly way) (On some other models bending the camshaft).
Slight 'overspill' will cause the pump head to rise (inside pump self) causing diesel in the crankcase.
The most likely thing when these twins and threes aren't performing equal on all cylinders is dirt in the pump and injector.
Dirt causes the pump to spill differently as the piston is obstructed and when the injector is also dirty, incorrect injection isn't detected by eye.
Personally I just pull the injectors an test them. A lot can be determined by just testing injectors which are usually easy to locate and remove. These engines perform nearly with no compression and always amazes me how easy they start compared to something like a Wolseley.
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