pistons frozen, need to remove crankshaft

[thunder]

I have a '75 115HP Inline Merc. I want to remove the crankshaft to tranplant into another motor, but all six piston are "frozen" in the block. I don't care too much for the block, pistons or conn rods, but I do not want to damage the crank. Does anyone know any secrets to break the pistons free? Also, the bolts for the conn rod caps seem to be in backwards??? The nuts are pointing towards the piston, and the bolt head in toward the carb side. Is this correct??? If it is, it sure is strange. Any help would be appreciated.

 

[jimmbo]

Re: pistons frozen, need to remove crankshaft

On these motors that's how the rod bolts go. Have you removed all the rod caps? As for freeing the pistons? beat on them with a punch thru the sparl plug hole. Spray engine cleaner into the bores and letting it sit a couple of days might lossen the pistons.

 

[alcan]

Re: pistons frozen, need to remove crankshaft

Rig up a plug or plugs with a greese zirks in them. Screw them into the spark plug holes and pump greese to it. This will only work for the pistons near TDC.

 

[thunder]

Re: pistons frozen, need to remove crankshaft

Jimmbo, I haven't removed any of the rod caps yet. only two of them are in a position where I can get a socket on the nuts. All of the others are down into the block. I was thinking of taking a small grinder the to ro dcap bolt heads, and then using a punch to knock the bolts out. What do you think?

 

[jimmbo]

Re: pistons frozen, need to remove crankshaft

Should work

 

[Chris1956]

Re: pistons frozen, need to remove crankshaft

Thunder, I agree with Jimmbo. I would spray penetrating oil into the spark plug holes. Let it soak a bit, and then put a brass rod through the plug hole onto the piston and tap it with a hammer. It is likely number one or three are the rusty ones, so I would start with them. They ususally break loose without too much whacking!

 

[Chinewalker]

Re: pistons frozen, need to remove crankshaft

Hi Thunder,<br /> If you have access to a bench-press, it is fairly easy to knock pistons out. This could also save some pistons (which almost always are unusable after the beating it out method).. Roll the block over, plug holes up. Block the block up so that there is clearance under it and room for the crankshaft to move as a piston is pushed downwards. Using the press, one at a time, and a little at a time, push out each piston enough to access the rod bolts. Remove the nuts as they become accessible. By releasing each one as they become accessible, you reduce the risk of torquing the crankshaft and bending it. Once you have all the rods disconnected, remove the crankshaft, and THEN press out any pistons still in the block. You may find that some are more stuck than others. If some of them are one with the block and no amount of force is driving them out, then you may have to cut them out with a Dremel tool. Work slowly and carefully and you may salvage a lot more than the crankshaft...<br />- Scott