Cracked Engine Block

[quadfreakz400]

Alright I got a 1974 250 ci Mercruiser straight 6 with a huge crack in the block....just wondering if a 250 ci chevy engine block would work or if it needs to be a marine engine....if it does have to be marine where's a good place to look for used or cheap engine blocks....thanks in advance

 

[Fordiesel69]

Re: Cracked Engine Block

I don;t beleive automotive blocks are the same. I know the heads definatly are not.

I think it has to do somthing with the block. I was going to by an 84 sea ray but it also needed an entire engine.

 

[Fordiesel69]

Re: Cracked Engine Block

Oh, and I also can say for certain the I6 165HP merc engine will NOT be cheap unless you can find an old rusty one that needs rebuilt. You may get lucky and be able to bore it out and use it.

Is the crack just external? Or is it mixing oil & water?

 

[mikel1291979]

Re: Cracked Engine Block

Block is a block is a block. Install brass freeze plugs, marine or truck cam and marine head gaskets. Good machine shop will mill the block with a bit more clearance for the head in a marine application. Valves in the head are a little different as the metal in a marine head is a harder metal, can't think of the name of it though. Be sure to get a block with compatible casting numbers so you can still use your bolt ons.

 

[kewlkatdady]

Re: Cracked Engine Block

heads are heads...

Marine gaskets set, marine or truck/rv cam, brass plugs and bolt on all the marine externals.

 

[kilowatts]

Re: Cracked Engine Block

Hi Guys:

If all you need is a 250 cid block then you have to check that it has the same "ears" for the front motor mount or fabricate them. The bore needs to be the same for the pistons or new pistons are required. Other than that swap all the other parts from the cracked block which clearly needs care and attention along with miscellaneous parts as required although a reman short block is quite reasonable online. I've bought several fully dressed used inline six marine engines for less than $300.00.
Good Luck

kilowatts