nastee383

I have a loud clanging noise for about 3 seconds when I start the car and lately it would do it (intermittent) and lose power but recover. I put it up and went under to try and isolate where it was coming from. It appeared to be from the oil pan. I dropped the pan and took off the converter cover to inspect. Everything looked fine, except all 3 converter bolts were loose. That can account for the clanging noise, but could it be a cause for the intermittent roughness and loss of power? Maybe because of the external balance? Or could it be spun rod bearings? Can you visually see this condition without taking the rods out? There was nothing in the pan and no indications that anything was striking it from the inside, no dents, scratches or rubs. I rotated the engine while inspecting and everything looked fine. Tell me what you think it could be. :confused:

Oldguard 7

Get your self a mechanics stethoscope and touch the engine in the area where the noise is suspected it will be magnified. Old timers used to use a long screwdriver and can hear noise through the handle.

nastee383

ttt, it was a late post. Still need opinions. Thanks

Paul L

What do you mean by "converter" bolts?

nastee383

The 3 bolts that attach the torque converter to the flex plate.

Paul L

I was thinking cat con for some reason. They do rattle when worn out. As does the heatshield above it. The stethoscope (or bamboo stick) is good advice for pinpointing the source.

daves80

kinda sounds like a broken flex plate - hope not - dave

dually4wd

You probably found the problem already with the loose bolts. If you weren't loosing oil pressure, the bearings are likely fine too. Check the flexplate for cracks, then fire it back up to see what's up after the bolts are tight. Of course, you could always yank the 383, freshen it, put it in the Blazer, build a 540 for the Vette, bolt on a big nasty blower... :crazy:

nastee383

Hopefully that'll be the case. Oil pressure was good as always. I'll tighten/loctite those bolts and check closely for any cracks. Actually I was getting excited about the possibility of getting a 427SB shortblock. I guess the worst part now will be getting the oil pan back on without it leaking! I think I'll try one of those one-piece pan gaskets. Thanks :thumbs: