Cylinder wall thickness

Rich Biebel · 01-08-2021, 12:34 PM

What Chuck said is accurate and back in my engine shop days we hardness tested and sonic tested most Small Block Chevys and any block that was going to be potentially used for a race engine....

The Hardness test was easy using a Brinell tester and the blocks had a pretty wide spread on the numbers that you got on the test..

An ideal block was at the high end of the hardness scale and had thrust walls that would be .200" or more when finished.

You can easily see a badly core shifted block just by the cam hole and the machined surface at the face of it. The sonic test will show the cylinder walls being offset usually on a block with visible shift at the cam hole...

I was buidling a 383 for a friend and the block was so offset I could not get rods to clear one side at the bottom of the cylinders and the other side went right by......I changed what rods I was using for it just to make the fit and not grind the heck out of the block and potentially break thru to the water jacket....The crank and cam were not centered in the casting by a fair amount.....GM had some real odd ways of machining engine parts.....BB Chevy Iron heads is a good example.......Guide bores not centered with the guide OD

The Brinell numbers were from a low of around 200 to a high of around 245.....

A nice early 4 bolt 010 block with nodular caps was the best you could hope to find with good hardness and cylinder wall thickness....

Aftermarket blocks are a ton better......

01-08-2021, 12:34 PM	#7
Rich Biebel VIP Member Join Date: Jun 2007 Location: Northern New Jersey suburbs Posts: 2,314 Likes: 25 Liked 544 Times in 213 Posts	Re: Cylinder wall thickness What Chuck said is accurate and back in my engine shop days we hardness tested and sonic tested most Small Block Chevys and any block that was going to be potentially used for a race engine.... The Hardness test was easy using a Brinell tester and the blocks had a pretty wide spread on the numbers that you got on the test.. An ideal block was at the high end of the hardness scale and had thrust walls that would be .200" or more when finished. You can easily see a badly core shifted block just by the cam hole and the machined surface at the face of it. The sonic test will show the cylinder walls being offset usually on a block with visible shift at the cam hole... I was buidling a 383 for a friend and the block was so offset I could not get rods to clear one side at the bottom of the cylinders and the other side went right by......I changed what rods I was using for it just to make the fit and not grind the heck out of the block and potentially break thru to the water jacket....The crank and cam were not centered in the casting by a fair amount.....GM had some real odd ways of machining engine parts.....BB Chevy Iron heads is a good example.......Guide bores not centered with the guide OD The Brinell numbers were from a low of around 200 to a high of around 245..... A nice early 4 bolt 010 block with nodular caps was the best you could hope to find with good hardness and cylinder wall thickness.... Aftermarket blocks are a ton better...... __________________ Rich Biebel S/C 1479 Stock 147R Last edited by Rich Biebel; 01-08-2021 at 12:38 PM.