pullmytrigger

from a freeze up.....sbc.....about an inch below the deck

GOODT

yes it can be done but make sure you find someone that has done it before and is experiaced. have had it done have also used marine tex works great if preped right !

lowflyin

I had this happen to me once. I ended up freshening up that motor and going with another block anyway. I was told however that you have to be very careful with the heat to prevent cylinder wall distortion.

cmcnitt

I've seen one get welded once, with a stick welder. The guy put the bare block in his powdercoating oven and heated it up first. He said we was using a special rod also but I don't remember what kind it was.

GOODT

if it in the lifter galley or outer wall heat is not a problem because the water jacket acts a a air pocket insulating the cylinder from the heat depends on how deep you pockets are I am a big believer in doing it right the first time but have never had a problem with any block Ive had welded....don't think id do it on a 1200 sterling though if you get my drift.

but in a 15 yr old boat with a 350 in it thats another story

Liberator21

There are special electrodes to stick weld cast iron. BUT, you must heat the block up first or you could run into problems. A long time ago I worked in a machine shop, and we would get these castings in to finish machine. More than once one needed to be welded, and we always heated them in an oven before welding. See what it would cost to have a professional do it, and weigh that against replacing the block. SBC's are cheap (relatively speaking). Also, an inch below the deck could be problems because it seems close to the head bolts.

Whiteknuckle

Yes, it can be done by an experienced welder. What I mean by that is a guy that is experienced with cast iron. What you have to do is preheat the area around the weld. A tempurature stick is used to bring the metal up to the correct preheat. A special rod is used, usually one that has a high nickle content. One of the problems is to keep the crack from "running". Also, I have had good results with using a two part epoxy on cracks. The trick there is to be patent and be absolutly anal about following the directions on the product you are using. To fix a crack may take 3-4 days by applying thin coats of epoxy. Just don't let any smuck weld your block. He needs to have experience. Good Luck!

Big Block Billy

I've had good luck welding cast parts with 55% nickel rods. Preheat is absolutely necessary, as well as post heat to draw the heat away from the weld area gradually. I actually had the same problem with a motor I bought on e-bay that although rebuilt, there was a crack in the same spot you're talking about. I ground it with a disc grinder, cleaned with acetone, and used JB industroweld. $10 at autozone for enough to fix a dozen things. I had good luck with this repair on the small block. My dad, a long time automotive gearhead(since the early 50's) was very impressed with the repair as well. Sometimes, a quick fix can be a good, lasting repair if it is well thought out. BBB

Iggy

Like Whiteknuckle said, the block has got to be heated (400-500 deg??) or at the very least the area surrounding the crack. Welding will cause the crack to grow if not preheated from the shock of intense heat. And the crack will need to be hit with a grinder to create a chamfer before welding.
Allowing the iron to cool slowly is important too. The iron will get very brittle and could break like glass.

I used to weld all types of metals. Cast iron was the only material that I had reservations about. I welded many cast iron electric motor housings. They all held up, but I was uncomfortable about doing it.

jpclear

I like BBB's "quick fix" but I also drill and tap the ends of the crack and along it at 3/4 to 1" increments (#10), insert the screws, grind flush, and stake. This stabilizes the surface and prevents re-cracking with temp. changes. Then epoxy it up. You can even texture the surface by pressing with a shop rag while the epoxy is setting up for a perfect cast iron appearance. Paint it and "only your hairdresser knows". --- Jer