How do you separate cases when jugs rusted
 

I've dismantled an old 1969 911 engine and got it to the cylinders and cases stage. I can't get any of the pistons to move so I have no way to separate the cases.. Any advice??
Thanks....

I saw a picture the other day on which the owner cut the cilinder with a grinder.

I use a hole saw. Start it on center with the pilot bit, get the saw cutting, remove the bit and then cut down - through the piston - and around the wrist pin. A 3" hole saw usually does the trick.

I have had to do this several times. I use a die grinder with a heavy duty cutting wheel to cut a slot about 3/4 of the way down the cylinder being careful not to damage the case or the piston. I then use a chisel and a heavy duty hammer to split the cylinder open from the top. This frees the cylinder from the piston and allows the cylinder to be removed from the case, usually in several pieces. Most times it is not necessary to do this on every cylinder as only 2 or 3 are usually the offending stuck ones.

I had to split all 6 of the cylinders on my 2.2 using an angle grinder with a thin cutting disc. I used a pry bar to separate the piston from the cylinder. It was a lot of work but I managed to save the pistons only to find out that all of the rings were stuck.

If you tilt the engine on the side you could probably free the rings with phosphoric acid.

Thanks...
 

I'm going to try some of the methods you described..
Thanks for the help..
Steve

How badly are they rusted? I've been able to loosen them before by turning the engine on the side and soaking them with marvel mystery oil and then tapping them with a hammer and slide each cylinder off individually.

Kroil
 

Rotate the engine on its side and soak the P and Cs with Kroil. Vibration helps, and patience...is necessary. I just freed up a 356 engine that was partially submerged in a flood. A bet and beer was involved. Took two weeks, but it is now free.

Speedo

Coca Cola ...

maybe add a little heat to the jug too.

I once saw an old school mechanic use candle wak on bolt threads. The theory was that if you heat the bolt the wax would get sucked into the threads like solder and help them break loose. Never tried it myself.

I think both kroil and/or phosphoric acid are both a good start. In a pinch I would resort to WD40 before getting any saws out. Saws get radical at times, but other times they are 100% needed. With that 2.2 I would be very careful and precise. Berrymans makes a very high grade chemical dip that works wonders on things like this. I watched it melt rust once in front of my eyes.