Tapping noise, not valvetrain related?
04-25-2010, 10:14 AM
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Tapping noise, not valvetrain related? Well, here is a good one for you all. This noise started LAST YEAR. Last year I was doing a pull on the street, it happened at the very top of second gear. It was an odd noise, and then after I noticed I had a tapping noise at idle.
This happened halfway through summer so I just parked it until winter. Over winter I tore it down again, had new Diamond pistons put in and all new bearings. I wanted to freshen it up anyways. While tearing it down I noticed nothing wrong with anything which was odd.
Finish the car, start it, tapping noise is still there. Replaced all 16 lifters, and I found one slightly bent pushrod, replaced that as well. Noise is still there. Rockers all appear to be fine. Pre-load is fine on all cylinders, and when I had the heads off to replaced the lifters the piston was not hitting the gasket. I've pulled every injector plug off, no difference in sound.
This noise only happens between idle and 1900RPMS, after 1900 it is gone. Remember, the only thing I changed over the winter was the pistons and bearings, everything else was re-used. Oil pressure is good, 65PSI cold, 40PSI hot. Not fluctuation. The car is not down on power, not cutting cylinders and not throwing any codes. The noise does increase with RPM, but only to 1900 on the dot, then its gone.
It sounds a little louder off the timing cover with a stethescope. Could a stretched timing chain do this?
Any help is appreciated!
Build-
Livernois 404CI
Diamond pistons, Callies Crank, Manley Rods
Livernois Stage 3R Heads -Plenty of PTV
FAST 90
Kooks 1 7/8"
244/248 VRX7
This happened halfway through summer so I just parked it until winter. Over winter I tore it down again, had new Diamond pistons put in and all new bearings. I wanted to freshen it up anyways. While tearing it down I noticed nothing wrong with anything which was odd.
Finish the car, start it, tapping noise is still there. Replaced all 16 lifters, and I found one slightly bent pushrod, replaced that as well. Noise is still there. Rockers all appear to be fine. Pre-load is fine on all cylinders, and when I had the heads off to replaced the lifters the piston was not hitting the gasket. I've pulled every injector plug off, no difference in sound.
This noise only happens between idle and 1900RPMS, after 1900 it is gone. Remember, the only thing I changed over the winter was the pistons and bearings, everything else was re-used. Oil pressure is good, 65PSI cold, 40PSI hot. Not fluctuation. The car is not down on power, not cutting cylinders and not throwing any codes. The noise does increase with RPM, but only to 1900 on the dot, then its gone.
It sounds a little louder off the timing cover with a stethescope. Could a stretched timing chain do this?
Any help is appreciated!
Build-
Livernois 404CI
Diamond pistons, Callies Crank, Manley Rods
Livernois Stage 3R Heads -Plenty of PTV
FAST 90
Kooks 1 7/8"
244/248 VRX7
Last edited by losiguy; 04-25-2010 at 10:22 AM.
