I disconnected the torque converter and it still made the noise. I took the car back to the engine machine shop to get their opinion, they listened with a stethoscope and thought the noise was coming higher up than the crank area and recommended that I re-adjust the valves. I re-adjusted the valves and I learned that you if you quickly tighten the rockers the engine will run rough until the lifter bleeds down, and if you keep going you will eventually get to the point where there is no more bleed down (so at least I learned something).

The flexplate is a brand new napa unit and the flexplate bolts are brand new ARPs.

I think the most telling part is this:

The engine was originally running straight 30 wt oil. Today I changed the oil to Valvoline straight 60 wt racing oil. The knocking got louder, and not just after I restarted the engine for the first time - but literally the entire time it was running. It also sounded more like a rod knock (or maybe a secondary knock).

I think something internally is decreasing oil flow. I have no idea where the blockage would be, or if this is even likely. But all of the online information I have read said that a thicker oil should decrease the knocking sound if it's a rod or main (perhaps it would be louder right after startup but then quiet down.).

I don't know how the oil flows through the 250...I do know that the oil pressure gauge port has good pressure because 2 different gauges show pressure.

I also noticed that when I adjusted the valves I expected major oil splash (30wt oil at this point) - I did have good oil flow over the rockers and down the springs, but at idle I had no squirting over the head and my exhaust manifold stayed completely dry (I was on a relatively flat surface). So maybe this was normal? The oil pump is a new standard volume unit, the pickup is also new.

I've changed the oil filter 3 times now; the engine has about 300 miles on it. I changed the filter after the first 20 minutes, then again after about 50 miles, and then again today (with the new Valvoline VR1 60wt.).

Tomorrow I think I'll put some 5w-20 in it and see what it sounds like. Luckily I can re-use the filter and 60wt oil in my towing rig (I didn't drive on it, just idled).

What are the most likely cause of oil starvation in part of the engine? Are there any other places on the engine where I can check oil pressure?


Any other thoughts?

Thanks,


Dan