Big Block Question
Thread Starter
Burning Brakes
Joined: Sep 2005
Posts: 1,014
Likes: 11
From: Greenwich CT
Big Block Question
I pulled this block from my car a few months ago, there were no signs of any issues. As you can see there is a a crack on the journal. The bearing also exhibited signs of wear.
Can this be repaired? I'd like to sell the block but am unsure whether it has any value due to crack.
Its a 69 512 block.
Le Mans Master
Joined: Dec 2006
Posts: 5,557
Likes: 9
From: Oquirrh Mountains
St. Jude Donor '09
It got hot at some point. Look at the color changes in the metal around the journal. It looks like it may have spun a bearing at some point in it's life and was line bored?
Yes, it can be repaired. I've had cracks like this repaired in large diesel engines. It'll be fairly expensive because the block will have to be remachined b/c the process I'm familiar with, furnace brazing, distorts the block slightly. You'll be out a few grand. It's not an issue when a new block costs $40,000; but when one can be had for a few hundred, you have to really think about it.
http://www.precisioncastingrepair.com/
Yes, it can be repaired. I've had cracks like this repaired in large diesel engines. It'll be fairly expensive because the block will have to be remachined b/c the process I'm familiar with, furnace brazing, distorts the block slightly. You'll be out a few grand. It's not an issue when a new block costs $40,000; but when one can be had for a few hundred, you have to really think about it.
http://www.precisioncastingrepair.com/
Last edited by Ben Lurkin; Mar 12, 2012 at 02:01 PM.
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
U would need a welder and machinist to fix that.
That heat affected zone around the bearing saddle could mean future problems.
And i can see in your pix that crack goes deep into the outer brownish ring of the heat affected zone. And the crack is across the oil supply hole for the bearing which adds more work to recondition.
But on the other hand welding the cast iron there will heat the cast metal beyond cherry red as it puddles. To weld cast iron requires pre-heat above 400*F. BB won't fit on the barbeque - heads yes, block no. So you need not only someone that can weld cast iron but has an furnace (possibly just an oven) big enough for a engine block.
Crack first has to be ground out then pre-heated and flux applied.
Have to use cast iron filler rod though many use old piston rings if from cast iron material welding with ox-acetylene. Shielded metal arc (stick) needs specialty rod (nickle rod) and technique.
Then surfaces need machining to restore tolerance - but line boring should do it though the sides need to be machined too (and that oil passage to the bearing).
So the real answer is: how much is and original '69 512 block worth???
cardo0
And i can see in your pix that crack goes deep into the outer brownish ring of the heat affected zone. And the crack is across the oil supply hole for the bearing which adds more work to recondition.But on the other hand welding the cast iron there will heat the cast metal beyond cherry red as it puddles. To weld cast iron requires pre-heat above 400*F. BB won't fit on the barbeque - heads yes, block no. So you need not only someone that can weld cast iron but has an furnace (possibly just an oven) big enough for a engine block.
Crack first has to be ground out then pre-heated and flux applied.
Have to use cast iron filler rod though many use old piston rings if from cast iron material welding with ox-acetylene. Shielded metal arc (stick) needs specialty rod (nickle rod) and technique. Then surfaces need machining to restore tolerance - but line boring should do it though the sides need to be machined too (and that oil passage to the bearing).So the real answer is: how much is and original '69 512 block worth???
cardo0
