Help diagnose this tick/tap sound, video inside
11-12-2012, 10:49 PM
#1
Help diagnose this tick/tap sound, video inside I did a head/cam swap on my 5.3L about 3 weeks ago. Heads are new stock 799's milled 0.022, cam is a new 212/212 0.561/0.561 114LSA, new dual springs and Comp 7.325 pushrods, LS7 lifters with about 30k miles on them (were in the motor before the swap). I did not touch the oil pump or o-ring during the swap. There was a chirping/ticking noise once it got warm after the first start up, it lasted the whole 20 miles drive home but went away mostly the next day. I figured it was an exhaust leak that fixed itself. I babied it for many heat cycles, then I changed the oil a few hundred miles ago from M1 10W-30 to Rotella 5W-40. The ticking noise then came back a few days after.
It's a metallic ticking/tapping sound coming from the block area around cylinder 5 and 7. It varies with RPM and appears to be tapping at about half the speed as the engine is spinning (idle in videos is 650 rpm). The tapping happens at all temps, but is louder when warm. It does not seem to vary much with load. The oil pressure gauge is fluctuating slightly at idle. It did not do this before the oil change, but I also messed with the gauges themselves so I could have hurt the stepper motor or something. I put the front on jack stands to listen and the tapping noise almost disappeared... strange
I thought it was an exhaust leak but I have none, checked by hand and smoke. Pulled the valve cover and saw nothing. Retorqued all rockers and checked the springs. Lifter preload is 0.075". The lifters are LS7's with about 30K miles on them, looked okay when I put them back in. Compression on all cylinders is 180-185psi, cylinder 7 was 170psi. Could be user error however, it was the 2nd cylinder I did. I did not notice any abnormal metal on the drain plug when I changed the oil.
Warm-ish idle:
Warm-ish idle (notice the tapping comes and goes, skipping a beat here and there):
Warmer/hot idle after driving home 20 miles (tapping is consistent):
Spun bearing?
Collapsed lifter?
Bent pushrod?
Dislodged wrist pin?
It's a metallic ticking/tapping sound coming from the block area around cylinder 5 and 7. It varies with RPM and appears to be tapping at about half the speed as the engine is spinning (idle in videos is 650 rpm). The tapping happens at all temps, but is louder when warm. It does not seem to vary much with load. The oil pressure gauge is fluctuating slightly at idle. It did not do this before the oil change, but I also messed with the gauges themselves so I could have hurt the stepper motor or something. I put the front on jack stands to listen and the tapping noise almost disappeared... strange
I thought it was an exhaust leak but I have none, checked by hand and smoke. Pulled the valve cover and saw nothing. Retorqued all rockers and checked the springs. Lifter preload is 0.075". The lifters are LS7's with about 30K miles on them, looked okay when I put them back in. Compression on all cylinders is 180-185psi, cylinder 7 was 170psi. Could be user error however, it was the 2nd cylinder I did. I did not notice any abnormal metal on the drain plug when I changed the oil.
Warm-ish idle:
Warm-ish idle (notice the tapping comes and goes, skipping a beat here and there):
Warmer/hot idle after driving home 20 miles (tapping is consistent):
Spun bearing?
Collapsed lifter?
Bent pushrod?
Dislodged wrist pin?
11-13-2012, 03:46 PM
#4
If I go WOT in 5th at around 1500 rpm I hear a nasty rattling sound like pebbles in a soda can. Not sure if it's related. I've had a rattle since I owned the damn thing that comes and goes, sounds like a loose washer or a rock in the exhaust pipe. It could just be this.
11-14-2012, 12:39 AM
#7
Trending Topics
11-14-2012, 12:50 AM
#8
Engine has 108k miles. 30k on the lifters, most of which was with an LS1 cam. New heads and cam with about 500 miles now. I've taken to to 6000 rpm maybe a half dozen times since the cam/head swap. I drive it pretty easy otherwise.
11-14-2012, 12:54 AM
#9
Hmm... Mine sounded like that when I had a collapsed lifter but I had stock lifters with 120k and a mild cam
11-14-2012, 10:51 PM
#13
Pulled the oil drain plug real quick, absolutely nothing on it.
Hooked a mechanical oil pressure gauge up and it read 40 psi at warm idle, about 10psi less than what the dash gauge was reading.
Gonna get a leakdown tester soon and try that. Then maybe give longer pushrods a go, at least on the noisy cylinders first.
Hooked a mechanical oil pressure gauge up and it read 40 psi at warm idle, about 10psi less than what the dash gauge was reading.
Gonna get a leakdown tester soon and try that. Then maybe give longer pushrods a go, at least on the noisy cylinders first.
11-15-2012, 08:41 PM
#14
I measured the preload on a five of the lifters on the driver side using a dial indicator, and ended up swapping in 7.350" pushrods on two of them to get the preload above 0.070, including the exhaust valve on 7. It's amazing how much the preload can vary from valve to valve, but I guess it makes sense, there's many many factors involved
Anyways, there was no noticeable change in the tapping sound, if anything it's slightly louder but not to the point of saying I made it worse, probably just paranoia.
Gonna check the rest of the preloads tomorrow, but I think it's safe to say it's not a lifter preload issue.
Anyways, there was no noticeable change in the tapping sound, if anything it's slightly louder but not to the point of saying I made it worse, probably just paranoia.
Gonna check the rest of the preloads tomorrow, but I think it's safe to say it's not a lifter preload issue.
11-20-2012, 11:39 AM
#15
Little update... I checked the preload on each lifter with a dial indicator and ended up swapping in 7.350's on 5 valves to get between 0.075 and 0.100 preload, all exhaust valves strangely, some ended up around 0.095. Noise was the same. I may put them all back to 7.325.
Then I ran the motor with the rockers/pushrods off of cylinder 5 then 7 so these lifters weren't being used. With the rockers/pushrods removed from cylinder 5, the tapping was significantly reduced or gone. I did it twice to confirm. With them off 7 the tapping was still present. The lifters appear to be good; they compress and bleed down okay when the rocker is tightened, and pop back up with the rocker removed.
THEN, as a last ditch effort I switched back from Rotella 5W-40 to Mobil 1 10W-30 and the noise is significantly reduced, by 50-70% I'd say. Still a little early to tell, but the thinner oil has helped greatly. There is still a tapping sound, but it's more like the normal sewing machine than the metallic sound I heard before.
Anyone have thoughts to why a thinner oil would help? With the 160* thermostat and e-fan settings it cruises at 173F and idles around 185F. Hot idle oil pressure is now about 37psi, with the 5W-50 it was about 42psi.
Either way, sounds like the lifters need to be changed. And I may go with a higher pressure oil pump.
Then I ran the motor with the rockers/pushrods off of cylinder 5 then 7 so these lifters weren't being used. With the rockers/pushrods removed from cylinder 5, the tapping was significantly reduced or gone. I did it twice to confirm. With them off 7 the tapping was still present. The lifters appear to be good; they compress and bleed down okay when the rocker is tightened, and pop back up with the rocker removed.
THEN, as a last ditch effort I switched back from Rotella 5W-40 to Mobil 1 10W-30 and the noise is significantly reduced, by 50-70% I'd say. Still a little early to tell, but the thinner oil has helped greatly. There is still a tapping sound, but it's more like the normal sewing machine than the metallic sound I heard before.
Anyone have thoughts to why a thinner oil would help? With the 160* thermostat and e-fan settings it cruises at 173F and idles around 185F. Hot idle oil pressure is now about 37psi, with the 5W-50 it was about 42psi.
Either way, sounds like the lifters need to be changed. And I may go with a higher pressure oil pump.
