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Having trouble removing camshaft from block

M

mitchbuck

Contributing Member
I have a parts engine that I am trying to disassemble, and I cannot remove the crankshaft & pistons from the block! I can get the pistons about 1/2 way out but then they won't come out anymore. Do I have to detach the pistons from the crankshaft in order to remove them or will them out in one piece? Thanks!
 
The pistons have be removed from the top of the block while the crankshaft comes out from the bottom. The cylinders are tapered, wider at the top and smaller at the bottom, not allowing the piston to exit from the bottom.

You have to remove the rod bearing caps and push the piston and rod assembly out the top of the cylinder. If the rod caps are attached with nuts to studs, you need to ensure the threaded stud doesn't scrape against the rod journal and damage it's surface. Tape around the stud threads or maybe short pieces of soda straw slipped over them will protect your crank.

Once the pistons are out, you can remove the main bearing caps and lift out the crank. Although, it sounds like you've already taken the main caps off. If so, I encourage you to put them back on finger tight to help support and stabilize the crank while you're removing the pistons.

Good luck.
 
Also, a 1/2 or 3/4 wood dowel and a rubber mallet sometimes helps. I have had well worn engines develop a lip that the ring won't easily pass. A little gentle persuasion on the underside of the piston helps get the ring past the lip. Honestly though, never seen an outboard block with enough run time to develop that type of wear.
 
The ledge that m smith is referring to is called a "ridge". There is a tool most engine rebuilders have that's called a ridge reamer used to remove the ridge.

I agree with him that it's not likely to be a problem in this case. However, carbon buildup at the top of your cylinders could present an issue pushing the pistons out. If you intend on reusing the block, you must not damage the upper cylinder wall trying to clean anything like that up. Again, the ridge reamer is typically used to remove the carbon buildup. But, in the event you don't have one lying about you can remove it using chemicals like injector cleaner or acetone.

I thank m smith for pointing this out.

Good luck

Again
 
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Thanks for the input everyone. Looks like I need to detach the pistons from the camshaft and try again.....will post results.
 
You detach the connecting rod cap from the crankshaft. The piston pushes up through the top side where the head mounts. The camshaft is mounted on the cylinder head is a different part. I have never messed with the overhead cams, so I cannot comment on that removal process. I am a V8 hot rod guy.
 
Well I'm a dummy I realized that I wrote "camshaft" in title and "crankshaft" in the thread!!! I did mean crankshaft and yes I know the difference haha. Still haven't had a chance to address this hopefully this week.
 
Ok, update time! So I got ahold of a impact drill and was able to unbolt the piston rods from the camshaft. The pistons then slide out relatively easy out of the block! So problem solved and thanks for your help here! This engine had a piston failure so I'm trying to part out the powerhead now....
 
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