I had a reputable machine shop rebuild a 283 SBC for me. Upgraded parts and wasn’t cheap.
I broke the engine in on my run stand with 30W Lucas high zinc break-in oil. No issues at all.
Then in the truck for some gentle driving. Got about 600 miles on it and then it started making a bad noise.
Here’s a video link.
VIDEO LINK.
Machine shop pulled the oil pan off and said the bearings looked fine. They suspected it was a bad fuel pump making noise but I tested that fuel pump (see video) on a good engine (another 283 SBC) and it checks out ok.
I suspect the fuel pump lobe on the camshaft went bad. The shop is gonna tear it down and tell me what they find.
Ideas?
