Cracked blocks....fixable?

Mr. T · #1 10-22-2003, 03:22 AM

I have a 350 chev engine I just tore down. When I took off the intake manifold, I noticed there was a crack in the lifter valley, just above the lifters on the side wall. Does anybody know if this kind of crack is mendable? If so, who would I get in contact with? Thanks! [img]/ubbthreads/images/graemlins/flag.gif[/img]

Mr. T · #2 10-22-2003, 03:25 AM

The crack isn't deep and it is about 2.5 inches in length.

**PxTx** · #3 10-22-2003, 12:24 PM

I have seen a repair where a machinist will drill holes at each end of the crack, which is supposed to stop the crack from traveling. He then continues to drill in between the crack creating a series of holes which touch each other. These holes are then tapped for threads. A bolt or somthing is then threaded in each hole, with the threads locking into each other with a slight overlap at the 9 and 3 o'clock position. The bolt heads are broken off so that the next bolt can be tapped right next to the last. Kinda get the idea?

Paul T

**DaveC68** · #4 10-24-2003, 11:38 PM

I believe, you'll find the process is called "pinning".
I had to have it done to the 427 in my 69 corvette a few years back when rebuilding.
Couldn't afford to lose those "numbers" and original block.
Once done the repair was nearly invisible, and held up to @6 years of fairly agressive driving...and still going strong [img]/ubbthreads/images/graemlins/headbang.gif[/img]

Chevy454 · #5 10-24-2003, 11:41 PM

Indy cylinder head can fix it.

NCGuy68 · #6 10-25-2003, 01:24 AM

Had the same problem with a 396 L78 block a while back.
A friend, who is a tool and die maker, drilled a hole at each end of the crack. Using a die grinder, he cut a 'V' groove along it from hole to hole. He heated it up and then 'stick' welded it using the proper rod for cast iron.

The block/assembled motor is still running strong today.

**Salvatore** · #7 10-25-2003, 05:48 AM

Doing the same with with a small block. V it out at the cracks and weld it. It is cracked at a starter bolt hole. Works good! [img]/ubbthreads/images/graemlins/biggthumpup.gif[/img]

**PxTx** · #8 10-25-2003, 03:59 PM

I've welded cast iron with nickle rod in reverse polarity. That is how I welded the axle tubes to the housing in my 65. I'm told the real key is to heat the iron, weld it, and lower the temp very slowly till it cools. I did not do this, but my welds are still holding.

Paul

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