CC:

So you’ve just finished your LS. Everything is in it. Everything is to spec, the crankshaft, the camshaft, the heads have gone down right, and now you’re getting ready to seal it up. What should you be paying attention to? The one thing that’s even been in TSBs from General Motors is block porosity.

This is not a structural issues, it’s more of an appearance on some of the mating surfaces for the gaskets. What is a pore? Essentially it’s a void that happens while the part is being cast. That part can essentially have a tiny hole and when it’s machined down it can get larger and larger, or even smaller, depending on how deep you go or where it’s located.

You need to look for these. If you see one there’s a couple of options. Sometimes you can get away with just RTV over those pores to help the gasket seal. In some cases you might want to send it back to the machine shop, but you’re always running the risk of exposing more pores and more voids.

The most important thing to do is do not go after this with an abrasive disc to eliminate those pores. Chances are you’re going to get an uneven surface and it’s going to make it even harder for a gasket to seal. Pay attention to these, especially with a water pump and front cover go on the engine. So with this knowledge you could seal up the engine and you’ll know that it’s not going to leak.

I’m Andrew Markel. Thank you very much.

This video is sponsored by Elring Das Original