letitsnow Posted May 8, 2010 Share Posted May 8, 2010 I have this clearly audible knock starting at 2800rpm and continuing to 6k, it's only there on acceleration or cruise, not on decel. It's not there at idle. I drained the oil and cut the filter open(with a pipe cutter, not dremel), the only metal that I could find was so fine that I'm not actually sure it was there, and if it was it doesn't look like it could cause it. The valve clearances are set correctly, I checked them on several different occasions. I had hoped my free/practice engine would last at least a summer. Based on the lack of metal in the oil, I think it might be a flywheel bolt coming loose. I'm going to pull the tranny in the next few days, the clutch is already shot so I have to anyhow. Quote Link to comment Share on other sites More sharing options...
josh817 Posted May 9, 2010 Share Posted May 9, 2010 You sure you didn't get a load of bad fuel and its causing you to ping? Check your timing and see if its too far advance. A dizzy should be at full advance at those RPM's. Quote Link to comment Share on other sites More sharing options...
letitsnow Posted May 10, 2010 Author Share Posted May 10, 2010 Megasquirt, the max timing on the map is 35°(cruise rpm/map), actual timing does match the commanded timing. Timing at full boost is 24° going to 22° at 5200. Listening to it with a stethoscope, the sound is loudest centered on the side of no. 6 when free revving in the garage. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted May 11, 2010 Share Posted May 11, 2010 You're seeing 35 degrees advance at cruise AND pinging at 2800 rpm? Something else is not right. Just a thought: has the damper failed and started to rotate? If it did, the actual timing would be more than what you measured. That would explain the symptoms you describe. To verify: by hand, turn the engine until it's at TDC as determined by the #1 cyl valve lobes or via a screwdriver in the #1 spark plug hole and see if the timing mark is correct. I suspect you'll find it's not. Quote Link to comment Share on other sites More sharing options...
letitsnow Posted May 11, 2010 Author Share Posted May 11, 2010 I really doubt it's pinging, it's much too consistent. 2800rpm in any condition and it's there. I guess it doesn't hurt to verify TDC on the damper though, on the list it goes.... Last week of the semester followed by finals week means time is kinda limited. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted May 11, 2010 Share Posted May 11, 2010 My mistake, you wrote "knock" and I read "ping". Quote Link to comment Share on other sites More sharing options...
frank280zx Posted May 11, 2010 Share Posted May 11, 2010 Check your oil pressure sounds like you have rod bearing on its way out! Quote Link to comment Share on other sites More sharing options...
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