Bottom end overhaul
Posted: Mon Jul 13, 2020 11:10 pm
Hi all
My 1959 Dexta previously suffered from diesel getting into the air intake and eventually the sump. Initial symptoms were oily gunk spewing out of the exhaust, then oil spewing out of the dipstick then the most horrendous racing on startup after a rest period over winter. I was advised to fit an aftermarket tap but that was faulty allowing fuel through when closed (I tested it)! So I gave up and solved the problem by simply capping off the primer pump and also the glow plug intake in the air manifold with the intention of fitting the glow plug mod from Old 20 later this year. Since the cap off she has started and behaved perfectly, I fitted an oil gauge last year and it has consistently displayed 50 psi whilst she was both working hard and idling......until last week.
After a few weeks renovating a badly neglected field involving ploughing, pulling out strong but dead nettle roots and some largish rocks with my David Brown cultivator (marvellous piece of kit), then levelling, rolling and harrowing, it now displays 50 psi on cold startup then drops to 20 psi when warm. The crankcase breather is smoking a bit and she is getting through about half a litre of oil a week. She is still starting and working very well but there has been a knocking noise for a while which my old ears dismissed as a flakey water pump but I'm now thinking the crank is overdue a regrind and new bearings fitted. When I had the engine overhauled by a diesel engineer a few years ago the head was so far gone (he showed it to me) we decided to fit a new head complete with valves, and also new pistons etc. but he said the crankshaft was good. I've used Morris Golden Film SAE 20w-50 Classic in her for a couple of years now.
Before I present a cost benefit analysis to the Finance Director how much should I expect a bottom end overhaul to cost in the UK and what else do I need to make sure is replaced? This assumes I will deliver the tractor to a local restorer and not just the engine.
thanks in advance
Mike
My 1959 Dexta previously suffered from diesel getting into the air intake and eventually the sump. Initial symptoms were oily gunk spewing out of the exhaust, then oil spewing out of the dipstick then the most horrendous racing on startup after a rest period over winter. I was advised to fit an aftermarket tap but that was faulty allowing fuel through when closed (I tested it)! So I gave up and solved the problem by simply capping off the primer pump and also the glow plug intake in the air manifold with the intention of fitting the glow plug mod from Old 20 later this year. Since the cap off she has started and behaved perfectly, I fitted an oil gauge last year and it has consistently displayed 50 psi whilst she was both working hard and idling......until last week.
After a few weeks renovating a badly neglected field involving ploughing, pulling out strong but dead nettle roots and some largish rocks with my David Brown cultivator (marvellous piece of kit), then levelling, rolling and harrowing, it now displays 50 psi on cold startup then drops to 20 psi when warm. The crankcase breather is smoking a bit and she is getting through about half a litre of oil a week. She is still starting and working very well but there has been a knocking noise for a while which my old ears dismissed as a flakey water pump but I'm now thinking the crank is overdue a regrind and new bearings fitted. When I had the engine overhauled by a diesel engineer a few years ago the head was so far gone (he showed it to me) we decided to fit a new head complete with valves, and also new pistons etc. but he said the crankshaft was good. I've used Morris Golden Film SAE 20w-50 Classic in her for a couple of years now.
Before I present a cost benefit analysis to the Finance Director how much should I expect a bottom end overhaul to cost in the UK and what else do I need to make sure is replaced? This assumes I will deliver the tractor to a local restorer and not just the engine.
thanks in advance
Mike