JCB 3CIII - Misfire/Blacksmoke/loss of power (movement & hydraulic) help?

[stevejcb]

Hi

Stormin - To be honest I only remember checking it visually. There was definately some dipping around liner 4 though (I assume previous persons found that easier to emery). Q. Does water feed-up and around 1 and 2, I assume it does?. Whether the blow was due to protrusion, scoring or warping, or a combination of two or all three I'm not sure, but I do remember that most of the head bolts were not torqued to the spec with some of them in that region probably only reaching 60-70 lbsft. One assumes if it blows in that region again (heaven forbid) then theres something amiss.

[Jeremy Rowland]

Steve; I am pretty sure that you will be okay, it would be very surprising if the machine immediately blew a new head gasket, I would suspect even if there was an issue with the liner protrusion then you would still be able to complete the work that you want to use the machine for okay. The only time you may have a problem would be if the machine was working very long hours like a new machine would be used for, so all and in all I think you will be okay.

Jeremy

[stevejcb]

Hi
Update.

Rocker gear was examined, oil ways clear and clean. I disassembled rockers and spacers from shaft to check for wear etc. (both sides) – some slight scoring on shaft where spacers and rockers meet (to be expected), also one rocker internal face heavily scored – this was reused as I could find no associated scoring to shaft, perhaps this had been replaced at some point; anyhow I deemed it all fit for purpose, ports air blown. (pic av6 016)

[stevejcb]

As a precaution, I purchased two spare rockers (used) in advance, to replace those which had excessive wear to the profiled end, however, I was able to re-profile them all, using a fine file and then finishing them off with emery wrapped around it. (pic av6 020, 022)

[stevejcb]

With everything cleaned and air blasted, the rocker gear was reassembled with oil, in correct order and returned to the head. The positioning of the rockers on the pushrod ends is fiddly, (as they swing and then fight against the valve spring positions) so again the openings into the engine were ragged. After setting the gap between mounting blocks/rockers/spacers (which I did at 0.0250 – because I didn’t understand what it was supposed to be in the manual) I torque’d down the rocker gear bolts and then started on the valve gap adjustment – using the method of turning the forward drive shaft. This as previously discussed even with the injectors out was difficult – because it was underneath the digger in an inaccessible and space limiting position. I used an old screwdriver and a bar inserted into the universal joint (both ends) to turn it, moving sequentially from one to the other, whilst my son advised me when the order of the valves ‘open and closed’ were at their optimum (using the ‘9’ rule, i.e.:- 1 and 8, 2 and 7, ...). (pic av6 024)

[stevejcb]

With the rocker gear valves etc. given a good soak of oil, a new rocker cover gasket was oiled and situated, and the cover was located and screwed down. Inlet manifold cleaned and bolted to head using new gaskets (that fitted!). Injectors were given a thin smear of hp grease to their casing and then inserted with new copper washers and torque’d down, new fuel interconnecting pipes connected and then injector feed pipes secured. All other ancillaries were then reattached. Radiator and water pipes were hose flushed prior, secured, and then radiator filled with new antifreeze mixture. Exhaust manifold reconnected, plus the oil feed pipe from block. Having bled the fuel system, my digger was started – within seconds it was cranking over, (quickest time ever) sounding good, no black smoke and revving properly, hydraulics work fine. (pic av7 009,007)

[stevejcb]

To date I have used the digger for about twenty running hours (1 ¾ hours without stopping). The water in the radiator has remained static throughout, no loss and with no expansion. There was some water detection on the dipstick, but this might be due to past problem, as it has diminished with each use – a new oil change will happen soon. No fluid has emerged from the new injector sleeve, so I’m hoping this has sealed properly. Strangely the new hydraulic hoses which I replaced following the ‘blow out’ and the subsequent loss of fluid which I narrowly and thankfully avoided in the face, has not needed replenishing, despite also an initial leak from the steering actuator, which I think was from dry seals.
The manual suggest that I re-torque the head bolts after ½ hour and then at 50, - I shall do this now after I have finished the trench work at about 30, keeping the revs low till then.

Worst part – lack of knowledge, having never done a head gasket before.
Painful part – cranking the engine over by hand.
Annoying part – the damn weather!
Satisfying part – operating it again.

Overall I have learnt a lot, but I realise that there are limitations to how much I, and one can do, due to the heavy components. I hope my digger will now continue without another HG problem or worse. Anyhow I hope this forum topic will help others – (excuse the way I’ve uploaded it, but pictures really help). Many thanks to all for the comments. Obviously if anything changes there’ll be another update.

[Jeremy Rowland]

Well done Steve glad that all is well

Jeremy

[Hugh Jaleak]

Superb. Job well done, lovely sound hearing one of those running.