4.3 mercruiser alpha 1

[Jvanlue]

You need a breaker bar on the front end of the crank to turn the motor over, but not using the bolt that holds the pully/balancer on. It will break off in the end of the crankshaft, and now you are surely done.

There are a couple of different options for using a breaker bar, use the one you like best.

Just google "crank turning tool"

I have seen those, I may try one. Based on what I’ve posted, do you think this is a “vain attempt” to unseize this motor.

 

[alldodge]

Suggest
Don't try to turn it over, something else will happen. The motor can be rebuilt and it will run again, but need to just pull and start a rebuild

If you want to try and take a chance it freeing it up and run without a rebuild. Pull intake and heads, then see if cylinders can be freed. Rebuilt heads and clean everything else

 

[dave8311]

Pulling the heads and looking at the cylinders to see how much rust is in there would be a good idea, but you might get by with a bore scope in the plug holes.
If those rings are stuck, like rusted in place to the cylinder walls, if you do get it to turn you will probably score the cylinders or break a ring or ring land off the piston.

Just depends on how bad it's stuck.

 

[Scott Danforth]

Motor still won’t crank, I can turn it with a socket and breaker bar…. But the pulley wheel doesn’t move

all you are doing is wrecking the crank. as evidenced by turning the bolt and not turning the damper.

all you have done is stripped the threads out of the crank damaging the crank

never turn a chevrolet based motor by the crank bolt. always use a crank socket.