Lower Engine Knock?

[Old School]

Would a main bearing knock? Or would 99.9% of the time be a rod bearing?
The knock is coming from the rear of the engine. Any suggestions?

Thanks

[cudaken]

 Yea, get a rope and a rafter, that what I am doing now. Only main bearing had bad sort of bad was a Ford (yeck) 400. Main ratteled on start up after it sat over night and that was it. Knocking sound's like a Rod to me.

Check your flex plate for cracks, if you are lucky it will be bad.

More details would help, engine, history of engine with you, when knock happens RPM wise.


                                                   Cuda Ken

[Old School]

OK. Dont kick me off the site for this but it is on my chevy daily beater. Its a 350, and the knock started after I changed the oil one day.
I cant tell you how bad it sounds at anything other then an idle. If you step on the gas you can forget about hearing anything. Its really bad
at start up once the engine is up to temp it isn't to bad but still there. Its a 79 Chevy K10.

Thanks

[cudaken]

 More of a ticking sound? Would guess it is a liter if it happen after a oil change. What fliter and is it the same kind of oil?


                               Cuda Ken

[Old School]

Just a cheap Fram oil filter. To me it's a ticking sound. Not sure what oil was in it when I changed it.
just bought the truck a two months ago. I put 10 40 in it. I have 5 30 in it right now. The sound
goes away under load.

Thanks

[cudaken]

 I think it was Sliver R/T that posted about Fram being shit now. Try WIX fliter. Was the sound there with the 10W-40 or did you hear when you insalled the 5W-30 that is in it now? If you don't hear it under load I don't think it is a bearing.

Try some slick 50 and Moible 1 oil. My old BB had death rattels, not bearings just old with 152,000 on it. After the slick 50 and moible 1 sounded like a fresh BB.

                                       Cuda Ken

[andy74]

check the flexplate- nothing to do with the oil change,but i had a few chevy flexplates crack,and the sound would go away under load,at first!

[cudaken]

 Andy, you been speaking Mopar to long. Think they are called flywheels on GM. But Andy is right, a bad flywheel can make a racket as well.

                                 Cuda Ken

[472 R/T SE]

I had a main bearing go bad.  It was more of deep growl knock.  It happened one night when car was low on oil and I buried the speedo.

Have you tried using a long wooden handled screw driver yet?

[cudaken]

 My bet it is something to do with the oil. What little I know about using a stethescope you need to have a educated ear to be able to tell what you are hearing. Scott, tech from the local Dodge Deal thought my racket was coming from the rear of the 440. By ear, I thought it was the center or right front. Number 4 was the problem.

                                    Cuda Ken

[472 R/T SE]

I watched my uncle, dad use the ol' screwdriver.  My uncle diagnosed mine, I didn't believe him until they took it apart.  I don't have the knack for it, but it sounds good when you mention it.