[burntblacktoast]

Ok so i got a stuck 350 engine. head is off, pistons exposed. left side cyl, free. right side piston is holding on for all it is worth. it is soking in PB blaster (not peanut butter), i scrape all loose crud from around the piston/cyl, whack a few times with a rubber mallet just to get some molecules moving, repeat a day later. what other types of voodoo spells have yall had to invoke to get pistons undid? heat, pressure, violence? i am up to suggestions

 

[oneworden]

personally i would try to heat around where the piston and wall meet, after warming then spray with peanut butter. there will be a lot of cool smoke you don't want to breath in, but it will get the blaster in there deeper.

oh yeah then get a bigger hammer...

 

[burntblacktoast]

i like the way you think

 

[FR]

How did it sieze in the first place? Rust, or mechanical "interference"? Do you think the crankshaft turns? You can apply heat to the cylinder, it's going to need a hone at the least, maybe a bore, so I guess you can't do too much more harm with heat and force...


FR

 

[bmartin]

If the oil treatment is not working and the piston is going to be replaced, you can try a cold chisel and take the piston out in pieces. Reverting to a blow torch might do more harm than good. Another way to whack it with force is to use a 2x4 on the piston and a steel mallet on the other end of the 2x4. Be careful - too much force might kill the lower bearing and or the rod itself.

Unless the ring is embedded in the side wall of the bore, the oil treatment should work fine to free the piston given enough time. Thinking a little more about this - Is the piston cocked to one side in the bore??? If it is, you can try tapping the piston square again in the bore.

good luck and keep us posted...

 

[burntblacktoast]

Thanks for the replies so far, let me lend some more info. the engine was siezed when it came into my possesion. due to the looks of a cam lobe or two and some rocker faces, oil starvation may be the culprit, i have not inspected all of my passages yet. I do intend on a bore job and over sized pistons so a chisel is not a terrible idea. FR, the crank does rotate at least a little. it is stuck pretty darn near TDC because the cyl will only raise up a little when a turn on the crank. i think that if it were stuck closer to the middle the cylnder would travel further up and down both CW/CCW since the other piston is free. you know, as one unit. This brings me to bmartins suggestion not to apply too much force in regards to the rod or bearings being damaged. if the rod was at more of an angle any force i would use would be move the crank down and around. if it is as near vertical or TDC as i believe, most of that force would be going straight down, through the rod to the bearings....uhh, maybe i will stop wacking it as much

 

[UngaWunga]

Block of wood on top of piston, very large hammer.

 

[burntblacktoast]

enablers

 

[2smokeTyler]

marvels mystery oil...i have seen the stuff work miracles, though last time i used it, i let it sit in the bores for 3 days