[Luke303rd]

I have stripped down the motor in preparation for new cylinder heads, headers, and cam, and found this under a head bolt in the lifter valley. It's barely visible. I was wondering how bad a crack this is and what I can do about it. Thanks.

PS-Thanks for the info on the photo hosting site, I used www.tinypic.com. Thanks TwinTurbo.

 

[TwinTurbo]

you could have it pinned but for what it costs, better get a fresh block. it will propagate. you could try some of that muggy weld stuff, maybe if you pre heat some coolant and pour that in the block and let it cool down very slowly...maybe it'll work. Have seen that done on caterpillar engines, Personally I'd replace it

 

[big2bird]

As I see it, you have two choices.

Go ahead and do your thing, and run it till it breaks,or

Pull it out and change the block.

Pinning and cast iron welding is iffy at best. I have had both done with RARE blocks worth saving. Both methods are "iffy" at best.

Personnally, you have nothing to lose at this point. That crack may very well have been there for years.

 

[Luke303rd]

It doesn't seem that critical where it is. It is so small too. Then again, I know next to nothing about the severity of this type of crack. But I don't really have anything to loose. I think I might just do my thing and see what happens.

 

[Luke303rd]

I was planning on replacing the block over the winter anyway, and on top of that, I'm not pushing 20 psi of boost trying to get 800 hp out of it. It will be driven rarely in the coming months till winter anyway.

 

[big2bird]

It doesn't seem that critical where it is. It is so small too. Then again, I know next to nothing about the severity of this type of crack. But I don't really have anything to loose. I think I might just do my thing and see what happens.

There you go. Worst that could happen is a cracked block. Your ahead of the game already.:laughing:

 

[Luke303rd]

what about stop drilling the ends and smearing a little jb weld in there? To stop a leak if there even is one.

 

[TimAT]

I agree with TT and B2B, it should be replaced. Another option is to drill and pin the ends, then seal everything up, pull a slight vacuum on the whole block and then blue locktite the crack. The vacuum will pull the blue stuff in and help seal it. But as everyone else stated, it's a temporary fix at best.

:cheers:

BTW: were you running this block? And was it losing coolant?

 

[Luke303rd]

I have been running this block for about 5k miles since I bought the car. It hasn't been leaking anything. No moisture out of the exhaust or anything like that indicating a crack. What exactly is "pinning" the crack mean?

 

[yellow73sb]

Get some ceramic block sealer and call it done lol

 

[AK's Z06]

Take a minute and go over it with a small grinder to see if it cleans up. After removing some material, spray some brake cleaner on it, blow on the area, the crack will dry last, if its there. :thumbsup:

 

[TimAT]

"Pinning" the crack is to drill a small hole at each end then drive a steel pin into the holes. The crack won't propogate beyond the holes, and the pin just seals them up.

 

[turtlevette]

"Pinning" the crack is to drill a small hole at each end then drive a steel pin into the holes. The crack won't propogate beyond the holes, and the pin just seals them up.

I thought you had to grind the crack out all the way through and pin the whole length. Its a painstakingly time consuming process.

We tend to have a large number of "perfectionists" on these boards. In reality, you could probably drive that car the rest of your whole friggin life and never have any problems.

But now you know its there and if you are the Monkish type it'll probably drive you to your grave early.

 

[yellow73sb]

Yep what you don't know wont hurt you

 

[Duke94]

what about stop drilling the ends and smearing a little jb weld in there? To stop a leak if there even is one.

The block on my 71' was cracked in the same place. The machine shop said they could fix it by doing what they called "stiching". Basically drilling and tapping a bunch of holes the length of the crack and threading in special plugs with some kind of sealant on them. Just couldn't bring myself to install a engine with a crack, even though it was the orig block. Used the L-82 short block out of my 78'. Still have the block in case the next owner wants "numbers matching".

 

[Luke303rd]

Thanks a lot for the info guys. I'll let you kow how the "new" motor turns out. :thumbsup: