crankcase busted

[jgriner]

ive always seen that the starboard side has been covered in gas, finally found the problem yesterday.

ive seen that their are some hairline cracks where the crankcase is connected to the intake manifold.

the cracks are on top of the bolt holes on the top/middle cylinder, i can not see the bottom cylinder enough to tell what shape it is in

what would cause this, when i got the boat about a month ago it had 147-150 psi on all 3 cylinders, can i get this psi with these cracks or has these cracks happened since i got the motor.

can stuff like this be repaired, can it be welded, or maybe jb weld.

if i have to replace the crankcase, how much should i expect to pay for the parts?

 

[1946Zephyr]

Re: crankcase busted

What model of motor are you working on? In a case like this, it's usually best to replace the engine block. Trying to patch cracks will often invite more issues down the road.

 

[jgriner]

Re: crankcase busted

What model of motor are you working on? In a case like this, it's usually best to replace the engine block. Trying to patch cracks will often invite more issues down the road.

1979 75hr johnson stinger
75elr79r


that sounds expensive, and maybe a hard find

 

[F_R]

Re: crankcase busted

Can't tell from here, but crankcase cracks usually happen from the inside when the motor has broken a connecting rod or bearing and it is hitting the case. If that is what is happening, you won't have to worry about it much longer because it is on the last go-around.

Seems odd that it is cracked in two places though.

The crankcase is matched to the cylinder block and cannot be replaced separately. In other words, extremely expensive.

If I am guessing wrong, and it isn't hitting the inside, go ahead and JB it.

 

[jgriner]

Re: crankcase busted

Can't tell from here, but crankcase cracks usually happen from the inside when the motor has broken a connecting rod or bearing and it is hitting the case. If that is what is happening, you won't have to worry about it much longer because it is on the last go-around.

Seems odd that it is cracked in two places though.

The crankcase is matched to the cylinder block and cannot be replaced separately. In other words, extremely expensive.

If I am guessing wrong, and it isn't hitting the inside, go ahead and JB it.

the cracks run around those bolt holes could someone over thighening the bots cause it, it looks like maybe just have been rebuilt