hello gang...
So here I am with my fully rebuilt '69 LM1 which by the way is running fantastic. Smooth as silk, engine is steady as a rock at idle, and you can feel the power even though I haven't jumped on it (because I'm still breaking it in). I got to this point because of a lot of solid advise from folks on here...thank you. Especially Grumpyvette who gave a lot of good and well thought out advice.
So after all that, there's one thing bugging me. The oil pump seems to be "noisy". Now Grumpy if you're reading this know I've already been to your forum and read the links on pump noise and that it shouldn't really have any, causes etc. So let me first qualify "noise".
As the engine runs, you can here a whirling almost like a belt driven accessory or gear whine but its quiet enough that you'd never notice if you weren't looking for things (new engine, after all). Using a stethoscope I confirmed it is loudest at the sump end of the pan. The stethoscope defined it better to be a little more of a sound you would expect from two gears meshing. Once the engine is at operating temp it becomes undetectable to the ear.
The pump is a new Melling M155 with helical cut gears, (shark tooth) with the stock (58#) relief spring. I used Mellings steel-coupling drive shaft and confirmed it to be the correct one for the block. I opened the pump and measured everything inside for clearence and all was good, and I put assy lube on the gears and then primed the pump with oil before install. There is lots of distributor to drive shaft clearance, with the disty fully installed I can pull the rotor up almost 3/16", if anything it may be too much clearance. Finally the pan was clearanced to the pump, the pickup was set 1/2" pff the bottom of the pan including accounting for the felpro 1-pc gasket. When I drill-primed the engine, I thought the pump was on the loud side but other than volume, no unusual sounds, and it spun without any kind of binding. Oil pressure is great and consistent. I'm running Brad Penn Grade 1 10W30
I feel like I've done everything right, but it feels wrong that I should be able to hear it at all with the engine running. Before the rebuild I never heard the oil pump. But then again that pump was 48 years old with 130K miles on it and God knows how clean the oil may or may not have been before I got it, or how much wear it may have had. But the M155 is a higher flow pump (but not HV - those things are taller and need a different pan, and would be too much for my stock rebuild with stock bearing clearances) so maybe being new + higher flow, it makes more noise.
Finally, I called Melling and they said "oh yeah, don't worry about it". But its the oil pump, and a new engine. Of course I'm going to worry. Its what I do best in the absence of sound facts.
So tell me, am I being paranoid?