Whirring noise...normal or an issue?
 

Hey guys Ive recently had my 370 line honed for arp mains and bored .040 rebalance etc to fix it's previous builders issues. Piston to wall clearance is 5 thou after plateau hone new bearings rods and mains are now at .0022 and I set thrust at 5 thou. Oil pump was aligned properly as well as converyer to flexplate distance. Once I put my "sleeper" exhaust on I noticed the engine had a faint whirring noise coming from the pan which is more noticable when warm. With a screwdriver I listened and it seems to be coming from the front to center area. I had my machinist/old boss listen to it and he said it doesn't sound bad and is probably normal but thought it sounded more like my trans pump echoing through the alum pan. He isn't used to hearing an engine that's this quiet so it's kinda in the back of my mind. Oil filters all have been clean every oil change but I'm beyond anal with noises. Idk if it's from being a loose toleranced engine or the fact his old school machinist said the noise could be coming from the helical style gears in the oil pump or that im hearing the torrington bearing in my timing set. I just don't know if it's something I should worry about or if I should just stop worrying but its a 12k investment and I'm now flag broke lol. Also oil pressure is about 58 hot with 15w50 and 70-75 @wot.

How much run time/miles on the engine?

I think 400 to 450ish

Could just be that you're hearing the rings on the cylinder bores. They're much louder before the engine is really broken in. They make a faint scrape noise when you crank an engine with a ratchet after assembly, which can sound like a whirr at running RPM.

Hmm does make sense we ended up using stainless rings and I know that's a tough surface . I'm hoping I'm just over reacting and that it's something minor. It's probably got 15 hard pulls on it and runs flawless other than the low rpm bucking but it's a large cam with big time rotating mass. The only way I can describe it is just like a dull whine/whirr but what your saying does kinda make sense just don't know why it's louder in some areas ya know?

Nobody else has similar issues or the same sound?

Thinking about it as well do you guys think there's any chance the oil pump somehow could have shifted? I mean I can't think of anything else that would make that noise other than the pump/timing chain.

I just thought about it. Harmonics could also cause a whine correct? I just noticed only at idle my asp ud junk has a slight wobble to it which with any increase in rpm goes away as well as the noise