Okay; so I have the head and top end off my 1964 CA77 305, and I can't seem to budge the pistons; I'm afraid they may be rusted to the cylinders. I've applied heat and pressure( a few good knocks with a wooden block and a hammer), but they do not want to budge.
The cylinder head itself is free of the case, but only by about 1/3 of an inch. The stuck pistons are not allowing it to slide off the pistons and come free. I shimmed up the space and thought I might be able to loosen them with a lot of heat, penetrating oil and a hammer(judiciously applied), but no luck....does anybody have an idea?
-John
Stuck Pistons
stuck pistonsJohn,
I hate to say it but it sounds like your pistons fall in the worse case scenario. The rust seal is bad enough to make this most difficult. Last winter I was looking at several stuck engines in my shop and I did enough research to find a photo of Bill Silver's method of using a universal puller on top with sockets and nuts to brace against the cylinder bolts and push the pistons down. On two of these engines I pushed the sleeves out of the block. That was the only way the damned thing would come apart. A re-sleeve would then be the order of the day in that case. I don't recommend that though. Then on one I drilled enough holes in the top of the piston to remove the crown to relieve the pressure and they came free. Drill shavings are the biggest concern here and a strong shop vacuum helps. These are very much extreme measures and by no means to be taken lightly but in some cases I didn't feel I had much choice. I used enough heat to boil the oil on top of the pistons and enough pressure to break the top ring of the sleeve and still it would not move the piston. Not an easy situation, please keep us up to date. RW John
Just position the engine so that the penetrating oil will not run out and leave for a (long) while. More heat, more blows with the wooden block might free it. My CB77 was so bad I ended up smashing the top off the liner and withdrawing the whole barrel over that liner (with plenty of heat). My engine had been under water for several years and the crank was rusted up. I had to use a dremel grinder to cut off the liner in the end. Patience is your best friend here but if that fails serious action is called for. You could try bolting a plate across the barrel and trying to push down with a big bolt, with a wood block underneath. Good luck! G '60 C77 '60 C72 '62 C72 Dream '63 CL72
'61 CB72 '64 CB77 '65 CB160 '66 Matchless 350 '67 CL77 '67 S90 '77 CB400F
Stuck PistonsThanks guys; I'll try both of those. I'm just worried that all those hammer blows will crack or otherwise damage the piston rod, and/or the transmission, from the transfer of force to the piston and down the rod to the transmission. Both the pistons are pretty much level in the cylinders - the tops of them are flush with the cylinder head top - but I guess it's not going to get any 'broker', you know? Any guess if they're at Bottom Dead Center, TDC, or what...??
Rustywrench, if you have a link to that puller method, that'd be great; And G-Man, that's what I'm doing now; I have a nice pool of PB Blaster sitting on top of the piston heads and I'll wait a bit to see if it penetrates. About the heat, though: I've been applying it to the liner around the piston, on the theory that it willl cause that to expand, thereby hopefully freeing the piston - am I doing this the right way? This is my first foray into an engine, although I've worked on my bikes for years. If worst comes to worst, I'll just take the engine apart around the piston... G-Man, Your bike was found under water?! I'm impressed; that's dedication! I'd think it would be easier to just find a replacement engine...What's the story with that? John
Not quite under water but that's all that came out of the drain plug when I undid it...... Crankcase and primary drive are good, but that's about all. I use a big blow torch on the barrel and also tried drilling the crown off the piston. In the end you just have to go to extremes. G '60 C77 '60 C72 '62 C72 Dream '63 CL72
'61 CB72 '64 CB77 '65 CB160 '66 Matchless 350 '67 CL77 '67 S90 '77 CB400F John
My CB77 looked like this. I like a challenge! http://www.flickr.com/photos/63154743@N ... 297956475/ G '60 C77 '60 C72 '62 C72 Dream '63 CL72
'61 CB72 '64 CB77 '65 CB160 '66 Matchless 350 '67 CL77 '67 S90 '77 CB400F John,
Here's pics of my home made tools in action freeing up a hopelessly stuck piston. This was the worst that I have come across in the 20 or so stuck engines that I've disassembled. The bad thing about this one was not only had it set full of water on one side but also it was infested by about a pound of mud placed there by an Oklahoma Dirt Dobber. The good thing was that is was only stuck on the right side. This setup works well for a 180 crank but you have to start with the highest piston first and shim up between the cyl and the crankcase as the cyl rises. The cyl will raise up if the opposite piston is also stuck. Try to press one side too much at a time and you could bend a rod. If both are stuck I just alternate from side to side moving each only a fraction at a time and shim the base as I go. With a (CA) 360 crank, which I have never done, I would think that you would need a similar setup pressing both pistons simutaneously. Press them both to bottom dead center, roll the crank to top center, shim under the cyl, and then press them out. Mark    FYI this engine set with PB Blaster 2 weeks before I attempted to free it up.
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
