v8 rebuild

hi guys can you tell me if rebuilding a v8 can the pistons be removed from the crankcase bottom without having to take the head off.
i would be changing seals bearings and shells.
the engine would be out of the car so turing it over on a stand would be easy, thanks

Why?

I would have to agree with Teflon; if the engine is out and you're dropping the bottom end out, why not take the heads off and do a thorough job? While you're at it, pop the timing case off and do the timing chain, refurb the oil pump, check the cam shaft and lifters. It just seems a bit short sighted to remove the engine and not do a complete strip and rebuild. If nothing else, I would have thought it is both easier and better to put the pistons in from the top which would mean the heads need to be removed.

I don't think the pistons would pass the crankshaft, and even if they did, how are you going to compress the rings to get them back in again?

Peter

the shells can be done from the bottom, but why would you do it the arkward way.

for the time it takes to remove the heads you'll spend more time poking things into place and no doubt it'll cause more issues later on, get the rings renewed bust the glase on the bores, new seals and bearings around crank, maybe even have crank ground. and obviously new seals as needed.

then do a thorough job on the heads and you will be set for a good few thousand miles of hassle free engine use!!!

better to do it correctly now than have the engine in and out a few times!!

surely if your going to overhaul the bottom end you should take the heads off, even just to put a new head gasket in

hi the only reason for wanting to leave the heads on is i have just rebuilt the top end and is running great apart from the oil loss.
i think the rear oil seal is leaking so engine out or gearbox out.
and start again as i dont think i can manage the gearbox.
why do you have to break the glaze on the bores and how do you do this.
so i was thinking of taking the engine out and have a total rebuild.
the block is great no water loss after 2000 miles.
so not sure which way to go now.
i have been qouted 400 to take the gear box out .
many thanks

The bore is not a 'smooth' finish, its should have a fine, cross hatch honed finish, that oil will stick to.
Over the years, burned oil on hot bores leaves a deposit of shilack, or a 'glaze' which oil doesn't stick to, and over which the piston rings will 'surf' letting oil past the rings into the combustion chamber, making the engine ruin smokey.
You can remove the glaze and put a new honed finish on the bores with a tool called a 'glaze breaker' or bore hone, which is like three thin knife sharpening witstones in miniture version of a radial washing line that fits in an electric drill. costs about a tenner, at a guess.
All you are saving by NOT taking the heads off is undoing ten or fourteen bolts, and the price of a pair of cylinder head gaskets.
If you have the motor out, and can re-fit the valley gasket and heads nice and neatly, without the hassle of working over the wings of the car in the depths of the engine bay, cramped by the bulkhead, if anything its easier, and more likely to be done more neatly, accuratly and well.... so the engine shouldn't suffer from it.