Changing mains- engine in situ
Discussion
Pupp said:
Anyone done this? Seemingly possible with judicious and dextrous lolly stick poking if the other caps from the individual being changed are all loosened. Just academic interest at this time...
It can be done Pupp but ......... I would not want to put my name to having a leak free rear main seal after though (unless you changed seal) 
your used/old may tilt in its housing as you refit the rear main cap which is going to be hard to verify until you have an oil leak 
fooling around with used rotating shaft oil seals always carries a risk IMO if you don't want to remove the lump I would at least remove the g/box and fly and renew the crank seal at the same time 
Edited by Sardonicus on Monday 9th December 15:19
Sardonicus said:
t can be done Pupp but ......... I would not want to put my name to having a leak free rear main seal after though (unless you changed seal) your used/old may tilt in its housing as you refit the rear main cap which is going to be hard to verify until you have an oil leak fooling around with used rotating shaft oil seals always carries a risk IMO if you don't want to remove the lump I would at least remove the g/box and fly and renew the crank seal at the same time
+1.. but then you have to ask which is the easyest to remove?.. the gearbox or the engine.. by the time you've messed around with the box working on your back etc... you could have the engine out... your used/old may tilt in its housing as you refit the rear main cap which is going to be hard to verify until you have an oil leak fooling around with used rotating shaft oil seals always carries a risk IMO if you don't want to remove the lump I would at least remove the g/box and fly and renew the crank seal at the same time Edited by Sardonicus on Monday 9th December 15:19
Why would you want to put new shells on a worn crank you might get a small improvment in oil pressure for a while but if the crank isnot perfect it wont last and may well fail fairly quickly only way to overhaul the bottom end is get the crank out and have it ground first undersize with suitable shells and new seals both ends.
John
John
Engineer1949 said:
Why would you want to put new shells on a worn crank you might get a small improvment in oil pressure for a while but if the crank isnot perfect it wont last and may well fail fairly quickly only way to overhaul the bottom end is get the crank out and have it ground first undersize with suitable shells and new seals both ends.
John
Hi John John
I doubt Pupp is doing this because of wear sounds like he maybe just topping & tailing the motor ready for the Turbo install no harm in that but ..... probably easy to get the motor out and on the eng stand with that oil seal faffing around anyway IMO Thanks for the replies... to clarify intent, I will be changing the clutch and flywheel soon, so just thought a new set of mains could go in too. Had the sump off over the weekend to install the turbo drain and it looked do-able subject to the rear seal issues that others have flagged. In a perfect world, I would re-grind/rebuild it but in my imperfect world (ie working on the car outdoors and trying to keep it as usable as possible) I'll be quite happy to *just* give it the best chance I can of holding together while I get my head round the turbo capabilities and tune (will be starting soft). There's nothing obviously 'wrong' with the motor so I'm not trying to fix anything but the bottom end has got a load of miles on it now, hence the query - next iteration will be with a built engine if and as when necessary.
Slippery slope, as a min even if the crank looks ok you should pop a mic over it if your going to all that trouble with the mains, and what about the big ends?
For the amount of work in situ I would whip it out and do it properly or not at all, crank could quite possibly be fine and just need a polish only, IMO or whip a cap of and have a quick gander, if it looks ok leave well alone till your have more time
Rich
For the amount of work in situ I would whip it out and do it properly or not at all, crank could quite possibly be fine and just need a polish only, IMO or whip a cap of and have a quick gander, if it looks ok leave well alone till your have more time
Rich
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