unclecameron

I was looking at the torque specs for the crank/flywheel bolts, not the flywheel/torque converter one, and snapped off a bolt. The motor (just rebuilt) is making noises, could that be related, or should I look elsewhere? I was going to pull it out and replace it if the motor ran, so now it does, but would that cause noises? It doesn't sound like a rod knocking or something, just whining sort of...

ol"blue

The "whining" noise could possibly be a spun bearing. Did you rebuild it? Did you check the rod and main bearing clearance with a snap gauge & mike or plastiguage? If not, is the engine guaranteed? How's the oil presure? I doubt the broken bolt would cause the noise. JMO

5-90

If a loose torque converter screw can cause a hard knock, I see no reason why a broken torque converter screw wouldn't cause the same thing.

If one has failed, replace all four (six?) out of hand. It's easier that way.

Note that torque converter screws are of a special design called "place bolts," and you're probably not going to find them at the local hardware store. Get them from the dealer (yech!) or find an aftermarket application that will fit (for instance, ARP has a kit for Pontiac that works neatly for securing the flexplate to the crankshaft on the 6-242. Remove a screw that hasn't broken and measure it - then look for that in other applications. It's probably ISO. Peruse the ARP site for an application that fits, and then go to the parts house and look for a kit for that application.)

unclecameron

I rebuilt the engine myself. The rods and mains were nicely within spec according to the plasti-guage, and I had the crank spec'ed at the machine shop, he said it looked fine. New pistons, rings, oil pump, head resurfaced and pressure tested. Pistons had assembly lube and assembled by the shop, all other bearing surfaces had lots of oil as they were assembled.

Really what it sounds like is something is dragging against the flywheel when it rotates. It really doesn't sound like a bearing failing, a rod knocking, etc. and the oil pressure is around 40psi at idle (after it spooled up following when the motor started running, I guess it was low at first, but not very long, maybe 10-15 seconds). I checked the dipstick and don't see anything metal. After running a bit, the pushrods stopping making as much noise, presumably because the lifters filled up with oil. Nothing else looks ugly, so that's why I was wondering if maybe that bolt stub backed out and is hitting something, or there's some flywheel interference related to that, dunno. Will try to pull the inspection cover and look at the flywheel. Is there anything else that might make such a sond? I might shoot a video with my phone so people can hear the noise, maybe I can get a second opinion like that.

5-90

Have a mechanic's stethoscope? Or a length of rubber hose with a metal stud in the end? You can use that to locate the nose within the engine, and get a better idea of what is making all of that racket in the first place...