Quote:
Originally Posted by Speedy
- why do I need to disconnect the rods before hitting the pistons with the wood ontop?
what should I soak the cylinders with?
diesel? (should I clean out the carbon somehow)
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Hi Speedy,
You should disconnect the rod big-ends (maybe even pull the crank out but mark the pistons, rod caps and main bearing caps for position and direction first (don't forget the pistons-mark the front side)) so that each cylinder can be treated individually. If you thump on a nice fitting block of wood on one piston (preferably round and gotta be flat if a flat piston crown) then the shock is trying to transfer to all the other 3 pistons via the crank and rods. And that's not good for the rods or bearings or gears/chain or valve train.
Also I've experienced agro from an engine rod flopping and one of the big-end studs marking a crank journal - NOT something you want to happen to your pride and joy!! So if the big end bolts don't come out (not personally familiar with jeeps) then find some plastic or rubber hose that is a snug fit over the threads (so it won't fall off on ya) and cut bits off to slip over the threads to save your crank from being marked. You could try tape but needs to be thick enough and might not want to stick.
Some engine blocks don't allow for the pistons to be removed out the bottom due to insufficient size/clearances. So you can only knock them down so far (carefully) and then have to push from the bottom up using a different bit of wood. If the stroke of the motor is long enough and there's enough clearance with the casting then they will come out below (e.g. Fordson E27N tractor has long enough stroke and enough mains casting clearance for piston with rod to come out without removing crank I think).
Also (dunno about jeeps) retorquing bigend bolts would be risky if the bolts have been strained before. Replacing them with new especially in diesels is probably advisable.
I've heard that old automatic transmission fluid is a good at getting past stuck rings - just takes a fair while - perhaps months.
I've read that not too stiff rotary wirebrushes in a drill can clean off carbon - so long as it doesn't remove metal then should be OK.
Regards
Alex