Freeing a stuck engine
(→Breaking the engine loose) |
(→Breaking the engine loose) |
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Many years ago the writer bought a Commer van with a stuck engine. The poor aftermarket ignition wiring (the van originally had a diesel engine) had caused the engine to quit. The vehicle had been idle for over a year judging by its tax disc so Plus Gas was introduced into the plug holes daily for over a week. Trying to force the starting handle stripped the thread on the aluminium alloy jaw nut so that method of attack had failed. Fortunately the defective alloy part had been discontinued and replaced with a steel part so the new part was bought and fitted. Unfortunately even when the starting handle had timbers clamped on it for extra leverage the engine could still not be turned! At this point the starter motor was tried but the battery was too weak. A new heavy duty battery was purchased and this succeeded in freeing the engine on the third impact (the current draw was so high that the earth braid smoked!) The engine then fired-up and ran OK and at this point the astonished seller rushed out and said "Are you an electrician or something?" It was a great van and basically all it needed was two weeks of soaking with releasing fluid, a new battery and some attention to the ignition circuit. Engines from boats which have sunk are much more difficult. | Many years ago the writer bought a Commer van with a stuck engine. The poor aftermarket ignition wiring (the van originally had a diesel engine) had caused the engine to quit. The vehicle had been idle for over a year judging by its tax disc so Plus Gas was introduced into the plug holes daily for over a week. Trying to force the starting handle stripped the thread on the aluminium alloy jaw nut so that method of attack had failed. Fortunately the defective alloy part had been discontinued and replaced with a steel part so the new part was bought and fitted. Unfortunately even when the starting handle had timbers clamped on it for extra leverage the engine could still not be turned! At this point the starter motor was tried but the battery was too weak. A new heavy duty battery was purchased and this succeeded in freeing the engine on the third impact (the current draw was so high that the earth braid smoked!) The engine then fired-up and ran OK and at this point the astonished seller rushed out and said "Are you an electrician or something?" It was a great van and basically all it needed was two weeks of soaking with releasing fluid, a new battery and some attention to the ignition circuit. Engines from boats which have sunk are much more difficult. | ||
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| + | When pistons are stuck really hard, heat, the wood block and the sledgehammer may all fail. Also note that striking the crown of the piston is a very bad idea so ones oak block should be relieved in the middle. If possible obtain some thick-walled steel pipe and machine it to be a clearance fit in the bore. Pressure can now be applied to the edge of the piston where it is needed. If some all-thread can be obtained that will fit the stud holes in the block a hydraulic jack can be rigged-up but the key ingredient is TIME. For example the writer was privileged to be shown a seized vintage oil engine that was about a hundred years old. Its owner had been soaking the piston with red-diesel for a year however he said that he would not be doing any work on the engine until the piston had been soaked for another THREE YEARS but not many people have so much patience. In any case one also needs to consider the three-score-and-ten aspect when undertaking such lengthy tasks. | ||
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| + | Plumbers suppliers sell pipe-freezing kits (BP of the Freon replacement -50C) so it is fairly easy to freeze a piston to try to un-stick it from its bore. Liquid Nitrogen is better (BP-196C) but its not so easy to obtain. Dry ice or even a carbon dioxide fire extinguisher are also very effective in creating sub zero temperatures (BP -57C). Propane which is easy to obtain boils at -42 degrees C but there is the fire hazard to consider. | ||
==After the engine has broken loose== | ==After the engine has broken loose== | ||
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