How do I know the bearings are bad?

I have a 350 in my vehicle (I believe it's a run of the mill engine, year is approx. 1984) and I believe the bearing to be bad. At first I thought it was the oil pump, but have been lead to believe other wise. The symptoms are low oil pressure once the engine warms up (and I am running 20/50 weight with an added qt. of lucas oil) and a knocking noise that accompanies the low oil pressure. I have changed the oil pump once to a high volume oil pump and that did not resolve the issue.How do I know the bearings are bad?
A lot of engines get rebuilt by people who are less than knowledgeable.

He may have told the truth.



Don't try to fix just the knock, because the WHOLE rebuild was probably shoddy.



Either rebuild the entire engine or buy a new ';crate'; motor from GM.

parts department. For MY money, the crate motor is the best way to go.How do I know the bearings are bad?
Hope everything works out well the second time around!

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My left front wheel bearing just started making a strange noise and acting like it didn't want to go when I pressed on the accelerator. A mechanic can tell you for sure - just go to one you trust. It sucks being a woman and mechanics think they can pull crap on you and sell you stuff you don't need.
It's hard to tell without hearing the sound but it sounds like piston rod bearings. It can be repaired and it's easier in some cars than others. A lot depends on how easy it will be to take the oil pan off, as the bearings are accessible through the bottom of the engine.



If you decide to have this repaired, it's probably a good idea to replace the main bearings as well. The main bearings support the crankshaft and are probably worn if your rod bearings are worn. The main bearings will also be accessible with the oil pan off.
there are cam, rod, and main bearings in a engine, not enough info, and what idiot told you to change the oil pump
A knocking sound and low oil pressure when warm are almost a certain sign of either rod or main bearing problems. If the rest of the vehicle is in good shape, you should be able to get a rebuilt engine installed for less than $1500. That might beat the crap out of buying another car and taking on new financing.
Sorry, I though you were talking wheels. I had oversized tires on my car and wore out the bearings. Felt like I was driving on speed bumps.
It's most likely main bearings. The crank will need to be polished or turned and new new bearings installed. $250 if you do it yourself.
listening to you it sounds like you know the main bearings are bad but need to confirm it.

As your engine idles just lightly give the motor some gas you should hear the rods rattle when you lift off the gas and you can decide which one it is by removing and grounding each spark plug ( if you haven't done this Don't it can be dangerous if you don't know how.) the point is if your rods are knocking you need a new engine