Engine porosity

What did GM use to fix cylinder porosity. I just finished a tear down on a

5.7 truck engine. In the #3 cylinder there is a spot avout the size of a pencil eraser. It has been filled in with something. I dug it out and it seems to be something like JB Weld. I decided it wasn't a block that I would use since it would need to go about .040 overbore to be useable. I sandblasted about 15 minuites and finally got all the filler out. It is obviously a void, not really porosity but just a casting defect. I know the engine has never been down, I personally know the man who bought the truck new and wore it out. Its clear that whatever was used works. The engine was at 187XXX miles and the filler wore just like the rest of the cyl. What do they use, where can I buy some/
Reply to
David Johnson
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I don't know what GM uses, but Cummins uses a Devcon (brand) putty to fill porosity and voids in their cast iron blocks.

Dave

Reply to
Hairy

Many years ago when GM have a lot of problems with this on a few engines, they used a epoxy to seal the block.

Reply to
TheSnoMan

Reply to
Shep

Reply to
TheSnoMan

I used to rebuild 2 cycle outbord motors, the ports are about the size of a dime and the pistons are humming along at 10000 RPM at Wide Open Throtle. I'm guessing that the holes were left at the factory and filled with carbon over time.

Reply to
dirtdude

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