Rebuilding 390 Engine

[davbell22602]

I was going over my 390 block today at school. So pulled everything down to the bare block.

Here's pics of the block where the main caps were.

When I pulled the camshaft out I noticed a cam bearing that was marked up. Its the one on the very front of the engine.

Here's pic the marked up of the marked up cam bearing.

I went to measure the inside diameter of the cylinders with a telescopic gauge then measured it with a outside micrometer and I got 4.077 on all 8. I went to to inspect the pistons and found that they have "30" stamped on them meaning 30 over. So measured the diameter of the piston with 4-5 inch micrometer and got 4.077 on all 8 pistons. I have 4.050 for stock cylinder bore. The piston to wall is .0015 when measuring with a piston feeler gauge. Does that sound right?

There are some surface scratches on the pistons on the side where the wrist pin doesnt go through at.

Here's pic the pistons.

 

[Nick The Great]

Neat stuff. I wish I knew more about this type of stuff. I overhauled a lawn mower engine in high school, but that was 10 - 12 years ago

 

[Bigredmariner]

I'm thinking you are gonna have a hard time getting those 4.583 pistons back in the 4.077 hole.

 

[PenguinLTZ]

Good math Jarrod

 

[KillaF150]

 

[Bigredmariner]

I know you just skipped a decimal or something so I was just fucking with you.

There are some surface scratches on the pistons on the side where the wrist pin doesnt go through at.

This area is also called the "skirt" of the piston. The upper most portion that is exposed to combustion gasses is commonly referred to as the "Crown".

 

[buRRp]

 

[davbell22602]

I'm thinking you are gonna have a hard time getting those 4.583 pistons back in the 4.077 hole.

I have to recheck my piston diameter measurement.

 

[daddy]

 

[PenguinLTZ]