New Block Or Reuse Old Block

guys I took my motor 351w out my 1976 carayelle mercrusier .... it was locked up and I used pb blaster but nothing so I took it apart and found rust in piston. should I get a new block or just clean the piston walls and get new pistons and rings.. or what do you guys think I should do and where to start?

http://s1281.photobucket.com/user/syngledad36/media/Snapbucket/BA71FAD6-orig_zps1c8a6fd1.jpg.html

 

Depends on the rest of the engine and what UR are doing and how much you can spend. If it's good,a hone may work or a slight overbore with oversize pistons will be cheaper-but then you may as well pay up and get a reman. unit

Reman is more $$- but paying for a boat tow,crashing into shore after blowing up,and/or drowning because your cheap engine rebuild failed is a lot more expensive and you will need to do it again anyways....

Wrong topic BTW

 

You will probably want to have the cylinders bored and install new oversized pistons. When the engine is torn down you will then be able to install new rod and main bearings. Worst case scenario, the crankshaft may need to be re-ground. Rebuilding the engine is a lot more economical than buying a new one. If the engine is seized up, then it needs a lot of attention, more than just new rings. While you have the engine down, have the head redone too. If the pistons are socked in, then the valves will be sick too. Figure $1500 more or less for a complete engine rebuild and maybe a bit more if other things need to be replaced.

There are a whole basket of other things that may need to be refurbished or replaced...like the water pump, alternator, starter, and if carbureted maybe a new or rebuilt one. If injected then the injectors may need to be serviced and new fuel pumps installed.

 

the engine was rebuilt about 10 years ago by old owner and he never ran it just turned it over to make sure it was ok.... after it was rebuilt he put the boat n shop and 10 years later sold it to me. he never even took it out on the water after engine was rebuilt... after I bought it I ran it to put a tune up it and then let it sit for about 2 years. some how water got in there and rest is all over the pistons... in side the v covers are so clean. the motor looks new inside all but the top of rings where rust is.

 

If it has good pistons, you can just clean the bores and re-ring it. The best tool is a set of stones so you only take metal off the rusty area. Rust sticks out so a stone will mainly take the high spots out.

 

with an old windsor that has been in sea water, the problem is the heads.
They eat out in the top of the exhaust ports.
Double check that one before you rebuild it

 

gonzo
so all I need to do is use stones to nock the rust off the walls, clean the pistons and re-ring then.. if pistons are bad get new pistons. if I use a stone do I need to get over size pistons and rings or just use the stones to clean the walls with.... and when you say stones ... what do you mean?

 

power
the motor was rebuilt 10 years ago be for I bought it and the old owner never put it in the water and I have never put it in any water so Its never been in the water after its been rebuilt say 12-13 years ago

 

The pistons will be fine if they were run almost not at all. This is the tool:
http://www.tooltopia.com/kd-tools-2...se&utm_term=KDT2833&utm_campaign=shopzilla_r1

 

so that's it just sand the use the stones to clean the walls, clean the pistons and re-ring and put it back together

 

Yes, that's about it. Remember to move the stones up and down to get a crosshatch pattern and keep them lubricated as you do. Kerosene or diesel fuel work well.

 

thank you guys so much

 

would you get the heads checked out for cracks or what..... I don't know how the water got in the pistons

 

You'll probably just need to hone a fresh cross hatch on the cylinder walls, assuming everything else is rust free. Since you have to pull the piston/rod assemblies during this, it only makes sense to check all the clearances. Since you seem to be in the dark about normal procedures, you'd be well advised to start from a level playing field, with new seals, checked clearances and new bearings. This isn't very costly if you do it yourself, less then a few hundred bucks, for seals, gaskets and bearings. You'll probably see issues with the heads, if you can't, take it to a machine shop and they'll check them out for not a lot of money.

A redone short block for a 351 Windsor isn't that much, ranging from a few hundred to several, depending on what you want. EBay will have several to choose from, but your local engine rebuilder will save you some shipping charges.

 

thank you guys