An engine build isn't necessarily just about hours.......
I have to agree with Stick .... still this is a very interesting subject and all of us would like to have some idea as to what it takes. Perhaps we can lay it out in the following format (of course only folks that actually engage in this type of work can make those estimates).
First; I would think that removing and reinstall steps of our engine is fairly routine and a range of hours to do this can properly be accurately established, I mentioned range of hours since one i’m Sure needs to allow for the unknown. So Shops that handle this on a regular basis should be in a position to provide a Customer with a fairly accurate estimate.
As for when the engine is on the floor (bolted in the engine support stand) the question of hours I think becomes a bit more difficult since we are dealing with the unknown as to what will be found once the engine is completely disassembled and all parts are cleaned for inspection and measurements. Only after the visual inspection and all measurements are completed will one know what will require to be replaced with new parts, what can be refurbished (and how long this would take) and what can be used as is.
To this end I would think that shops that handle inspection of our engines should be in a position to tell us the estimated hours of 1 to 3 I’ve listed as follows.
1) “Routine Engine Rebuild” a estimate of a routine engine rebuild were only a very minimum of parts are required to do the job.
2) “Minor Engine Rebuild” here an estimate could be made based up on a test drive and pre-inspection tests such as compression tests etc.
3) “Major Engine Rebuild” this might apply to an engine that is not operational and tests such as mentioned in item 2 above are simply not possible.
Again, I would think only professional shops that deal with this kind of work can provide those answers and then it needs to be in a range of hours to allow for continuances. Still then one needs to keep in mind it’s only an estimate.
My 2 cents
Dieter