Northstar Engines and System Technical Discussion Discussion, Aluminum Block porisity in Cadillac Engine Technical Discussion; While getting parts for my ignition system I section cut a block .upper right is the bottom of a head ...
While getting parts for my ignition system I section cut a block .upper right is the bottom of a head bolt hole and lower left is the main journal. you can see how many holes are in the aluminum . pretty low quality casting. The block halves are still bolted together so you can also see the sealant and oil gallerys.
In the other picture we see the cast in sleeve and the water jacket. notice the porisity here as well. I can definatly see why a timesert should be used on a H.G. R&R
I repaired the transmission case on a Porsche that was way worse than that. What you see there is pretty standard for pressure die castings. If you want to eleiminate porosity you have to go to sand castings.