Posted by Vaughn on Friday, June 20, 2003 at 10:51AM :
In Reply to: Clatter in engine under, is this right?! posted by Chris Becker on Thursday, June 19, 2003 at 11:43PM :
I would eliminate any valve problems. They are not impacted by loads on the engine.
Lower Bearing Connecting Rod knock - heard from bottom and normally a low deep sounding knock
Piston Wrist Pin Connecting Rod knock. Heard from upper engine area and not as low sounding - Possibility
Broken Piston Skirts - Clattering noise upper engine area
Timing to Advanced - Results in a high pitched ping - Possibility
Carbon Buildup - Same as lower bearing noise
You'll need to determine where the noise fits based on descriptions. I agree with the other comments that advance engine timing could be the cause. Timing should be set at 2 degrees ATDC. If you fine the timing ok, then you have worn parts enternally and you may need to tear the engine down and rebuild or start in lower gears and ease throttle to avoid the sound your hearing, or use high octane gas when you plan to pull a load.