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Engine Diagnosis / Overhaul

Failure of one journal could be due to a number of things, incorrect torque settings, insufficient lubrication when installed, poor bearing 'crush' from the rod eye, excessive wear on the journals (this would be evident on the other journals as well), so many different things could have gone wrong. I remember when fitting my own bearings, I had done one or two and as tightening another pair of the (new) rod bolts, and I got a 'feeling' about the amount of effort I was applying to bring the torque wrench to 'click', I loosened the bolt and rechecked the torque wrench setting, looked ok. Unwound and reset the wrench and tried again, somehow it did not feel 'right'. I stopped and after some running around managed to borrow another wrench, sure enough the tool had failed mid way during the install!!

If I had been inexperienced then I have no doubt, I would have kept applying pressure waiting for the wrench to click and instead the bolt would have broke/stripped.

You are lucky though, many owners would have ignored the noise and the result is the block is invariably wrecked as the rod breaks through the side casting. Depending on your finances then a second hand engine (with the bearings replaced) still may be the way to go. I note your comments about the valves being hit but no damage, that is very rare indeed.

regards

Dave
 
Failure of one journal and when all other journals have a low wear rate and are in good condition, could be due to a number of things, incorrect torque settings, insufficient lubrication when installed, poor bearing 'crush' from the rod eye, excessive wear on the journals (this would be evident on the other journals as well), old bolts reused? So many different things could have gone wrong. I remember when fitting my own bearings, I had done one or two and as tightening another pair of the (new) rod bolts, and I got a 'feeling' about the amount of effort I was applying to bring the torque wrench to 'click', I loosened the bolt and rechecked the torque wrench setting, looked ok. Unwound and reset the wrench and tried again, somehow it did not feel 'right'. I stopped and after some running around managed to borrow another wrench, sure enough the tool had failed mid way during the install!! I did document this in my long running 'MUD' thread (link below) many years ago. If I had been inexperienced then I have no doubt, I would have kept applying pressure waiting for the wrench to click and instead the bolt would have broke/stripped.

You are lucky though, it might not seem to be the case but many owners would have ignored the noise and the result is the block is invariably wrecked as the rod breaks through the side casting. Depending on your finances then a second hand engine (with the bearings replaced) still may be the way to go. I note your comments about the valves being hit but no damage. That is very rare indeed except in certain engines, Transit is a typical example, the push rods are 'sacrificial' but no such flexibility in an OHC design, the difference between no damage and damage could be as little as a few thousandths of an inch.

regards

Dave
 
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That's one of the reasons to use plastiguage to check you have not too little or not too large clearance. In the old days I had to measure the diameter of the journal and the internal diameter of the bearing to work out the clearance. Plastiguage does all this for you and just measures the exact clearance itself. One has to check journals all round for roundness first though.

Your lack of oil pressure may have been due to a faulty gauge and coincidental?
 
Your lack of oil pressure may have been due to a faulty gauge and coincidental?

Or could it be the gaps in the big ends getting bigger and letting the oil out? It was originally said that oil pressure had been low for months then failed altogether as the BEBs died after the engine flush. Perhaps the worst BEB was not the first to go but the first to lose oil when the others opened up enough to let the pressure fall to zero?
 
I've never had zero oil pressure even on an engines I've had with rattling big ends and main bearings. A well designed engine will have an oil pump with massive over capacity with a lot of the oil going past the pressure relief valve. As the bearings wear the valve closes up so oil pressure stays the same until bearing failure and pressure drops to a low level.
 
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