: Crankcase scrap rate.

01-05-05, 05:47 PM
Bobynski, what's the scrap rate on North* crankcase castings, start to finish? The chief engineer of one of the major aircraft engine manufactures said theirs was about 40%. Does GM sub out the castings or is it done in-house?

01-05-05, 07:16 PM
The Northstar block castings are done by a GM Powertrain casting division in Bedford, Indiana, so they are done in-house.

I cannot quote a specific number but I can tell you that we would have gone out of business ages ago with a 40% casting scrap rate...!!! It is more in the order of single digits at the highest....

01-05-05, 09:40 PM
The 40% number included everything from shifted cores to sand pockets and voids, warpage, failure to clean up, but also fixing everything that could be fixed with welding or other repairs. Maybe thats why an aircraft engine crankcase can cost $7500 on up. On the other hand, of the hundreds that I have personally closely inspected I have seen one new case that was mis-machined.

01-05-05, 11:23 PM
That is a hideous scrap rate. No wonder they cost so much....LOL.