Post by tom400cfi on Feb 1, 2011 18:45:02 GMT -7
My bro just came to town in his '99 Tacoma, with a "rod knock" noise coming from the engine. Engine is the 3400 V6 with the addition of the "TRD" Toyota Supercharger. The noise came on gradually as he was towing a U-Haul box trailer here from Denver...IMO probably over working the crap out of that boosted V6. He started hearing the noise in about Rock Springs, and it got louder progressively, all the way to Park City.
The noise is non existant when unloaded (coasting in gear) and gets worse with load. Also, the noise is worst when cold, and less bad when hot. These two symtoms are opposite my experience with a "spun rod bearing". Anyway, grounding the plug wires narrowed it down to cylinder #2, or the front drivers cylinder; grounding that plug wire eliminated the "knock" entirely.
Tonight, I pulled the front diff, and dropped the pan, and the #2 rod cap. The pan had metal flakes in it. Probably about 30 NON-magnetic flakes, all about 1/8" in dia...and then a "cloud" of fine metal particles above the sump in the raised part of the pan. Pulling the #2 cap, much to my surprise, revealed NO abnormal wear. Shells look basically brand new. Pushing on the rod, I can raise and lower the piston in the bore, with no discernable wrist-pin slop. So WTF? I don't know what the hell is going on here. I don't want to put the f'n thing back together, b/c it's going to continute to knock! Should I pull a f'n head and check the #2 piston? This is BFS, and the LAST thing that I need to be fiddle f'ing around with right now. Any advice is appreciated. I have a knock, I have metal in the pan, I can't find any damage.
-Tom
The noise is non existant when unloaded (coasting in gear) and gets worse with load. Also, the noise is worst when cold, and less bad when hot. These two symtoms are opposite my experience with a "spun rod bearing". Anyway, grounding the plug wires narrowed it down to cylinder #2, or the front drivers cylinder; grounding that plug wire eliminated the "knock" entirely.
Tonight, I pulled the front diff, and dropped the pan, and the #2 rod cap. The pan had metal flakes in it. Probably about 30 NON-magnetic flakes, all about 1/8" in dia...and then a "cloud" of fine metal particles above the sump in the raised part of the pan. Pulling the #2 cap, much to my surprise, revealed NO abnormal wear. Shells look basically brand new. Pushing on the rod, I can raise and lower the piston in the bore, with no discernable wrist-pin slop. So WTF? I don't know what the hell is going on here. I don't want to put the f'n thing back together, b/c it's going to continute to knock! Should I pull a f'n head and check the #2 piston? This is BFS, and the LAST thing that I need to be fiddle f'ing around with right now. Any advice is appreciated. I have a knock, I have metal in the pan, I can't find any damage.
-Tom