82' Mercrusier 470 cracked block replacement

[JAMN' Mantis]

The # 4 piston rusted or welded to the side of the block , and the # 3 piston rod is rusted in one position
S I have replaced the cracked block and am trying to find all the parts to start the rebuild

 

[Mercruiser420]

I think your original connecting rods are salvageable. So when you removed your original crank why can't you just pound pistons 3 and 4 out? As long as the rods are not bent they're usable. I'd double check with your machine shop what size pistons/rings/bearings you need and find a rebuild kit, that will include all the parts and gaskets you'll need for the rebuild. I'd get the camshaft checked/polished while at the machine shop.

 

[thumpar]

You can't just put standard Pistons in a block that is bored over. Have the shop tell you what size Pistons you need.

 

[JAMN' Mantis]

Hello,
Finally getting back ,while the block is at the shop .I've been tarring out the deck and it looks like the transom too .. oh boy
I was able to bang out the # 3 piston . maybe salvage the rod though rusted strait up and stuck ,so I may need just one rod .
Thanks for the info everyone about the size of the pistons. The Machine shop guy said the size will be 0.02 , so hopefully by the end of the week I can get them
I just need to break it up till I can find a way to pay for them . I am pretty hand and I have the time ,not always the money
Do you think I should buy a rebuild gasket kit . or buy them as I rebuild ? Is it cheaper ?
Thanks again

 

[Mercruiser420]

A rebuild kit usually includes all gaskets and seals (except the 2 camshaft seals that go in the front cover), pistons, rings and bearings. Probably the cheapest way to go. Make sure your camshaft is OK and won't leak. Get the crankshaft measured so you can order the correct bearings.