cracked block

[Preston]

I have a GM 4-cylinder that has been cracked on the inside of the block as well as the outside.<br />I have taken time to die-grind the cracks down and now I ma in question as to how to repair??<br />Anybody out there have any ideas?? J.B. weld or can I actuall weld these cracks up with a good nickel rod?

 

[mkast]

Re: cracked block

As I remember it, you have to heat the cast iron before you braze it. Less temp than welding with nickle. Can't you find a four cylinder in a bone yaard to replace the block?

 

[Preston]

Re: cracked block

according to the owner, it is quite difficult to find, however; I think that I can remove an industrial engine from an old Massey Ferguson swather and install in place of this motor. The motor that I have in mind is a 151 cid and is also a GM motor.

 

[CTD]

Re: cracked block

where are the cracks at? sometimes they can be welded. I've done some welding a spot lightly tapping on it with a pointed hammer to relieve stress as it cools then do another spot ect. If the cylinder wall is cracked sometimes you can rebore and install a sleeve.

 

[flashback]

Re: cracked block

Preston, there is a process called "stitching" that involves drilling and tapping holes along the crack and then putting threaded pins in the holes. this process works good if the cracks are not too numerous or irregular. do a search on "block stitching" and you will find some info on it.........I have heard folks using jb weld and such but I don't think it would be too reliable.

 

[SS MAYFLOAT]

Re: cracked block

I prefer stitching or lacing of the block only if the crack is external. If the crack is internal, scrap it. There is no heating involoved to distort your block with this method. If done right, it won't leak, will be strong, and can be easily ground down flush with the block. After painting, you cannot tell any repairs were made.<br /><br />Welding the block will weaken the area around the weld. Cast is very tricky to weld successfully. For a true cast weld. you would need to heat the entire block to over 800 degrees and then to let it cool evenly. Even after that you will need to have your crank journals line bored and trued. Then hope that your cylinders don't become warped.<br /><br />I'm sure if you spent some time searching different websites, you can find that block easily. There are lots of those available. Sometimes it is easier to find a whole boat that the hull is non-repairable to get the engine from. These boats are easy to aquire since the owners usually want to get rid of them.<br /><br />Good Luck

 

[Preston]

Re: cracked block

The cracks are inside the block opposite the camshaft, running from journal to journal, a half inch in from the cylinder. There is also a crack on the outside of the block running almost the full length of the block just below the deck where the head mounts. My impression is to scrap the thing, but the guy who owns it wants to try J.B. weld to see what happens. I know that the first time it runs hot all will give way and he will be up the creek. I feel as though it is almost a waist of my time----and it is kind of a neighborly free-bee. anyway thanks for all suggestions, and I think I will be looking for another block.

 

[captchas]

Re: cracked block

find your self a new block, cracks on the inside like you state are a death word, the 4 cyl. chevies are not hard to find and factory rebuilds are now avilable right from merc. the car motors are not the same on the inside not as beffie.<br />check out this web site you will find your motor, the rebuilds i personally have brought though it have been top notch with a 18 month warrenty on most