LC9 5.3: Valve noise after DOD delete
02-12-2021, 09:07 PM
#1
LC9 5.3: Valve noise after DOD delete Had a cam/lifter failure, did a DOD delete. Upgraded the cam to a 210/224 duration, .556/.568 lift. LS7 Lifters, and 1.8 set - 1.181 bind valve springs.
I used the comp pushrod tool to measure for my pushrods. I got 7.29" as zero lash, so I went with a 7.35 for a .06 preload. Triple tested both the measurements and the actual fit. I get about 1.25 turns on the rocker bolt after it touches. Rocker bolts are a 1.25mm thread pitch which would be .049 per turn, so this lines up with .06 fairly well.
I have only run the engine for about 5-6 minutes total, at two different times for about 2-3 minutes each. The first time it was obviously noisy for 20-30 seconds before the oil built up, and the noise level dropped a bit after. Shut the engine off, pulled a valve cover and rechecked all bolts. put cover back on and restarted engine. Still have a lot of valve train chatter.
Question 1, how long after a cam / lifter swap is normal for chatter on an LS style engine?
2, It has been in the 20 degree range temp wise, could this just be thick cold oil?
3, Should I have used some sort of pushrod or rocker guide plates?
4, Could I be limiting the max lift of the stock rockers?
Any help is appreciated!!!!!
Casey
I used the comp pushrod tool to measure for my pushrods. I got 7.29" as zero lash, so I went with a 7.35 for a .06 preload. Triple tested both the measurements and the actual fit. I get about 1.25 turns on the rocker bolt after it touches. Rocker bolts are a 1.25mm thread pitch which would be .049 per turn, so this lines up with .06 fairly well.
I have only run the engine for about 5-6 minutes total, at two different times for about 2-3 minutes each. The first time it was obviously noisy for 20-30 seconds before the oil built up, and the noise level dropped a bit after. Shut the engine off, pulled a valve cover and rechecked all bolts. put cover back on and restarted engine. Still have a lot of valve train chatter.
Question 1, how long after a cam / lifter swap is normal for chatter on an LS style engine?
2, It has been in the 20 degree range temp wise, could this just be thick cold oil?
3, Should I have used some sort of pushrod or rocker guide plates?
4, Could I be limiting the max lift of the stock rockers?
Any help is appreciated!!!!!
Casey
02-13-2021, 08:13 AM
#2
Valvetrain chatter is subjective. If your trying to compare the sound of a stock 5.3 to a cam/valve spring/cam setup, they just won't be the same.
Did you inspect the cam bearings before installing the cam? How bad was the cam/lifter you changed?
Does it sound like a sewing machine? That's the general description of the LS valvetrain.
Did you inspect the cam bearings before installing the cam? How bad was the cam/lifter you changed?
Does it sound like a sewing machine? That's the general description of the LS valvetrain.
02-13-2021, 11:05 AM
#3
TECH Senior Member
I don't know what the ramp rates are on that cam, but it is a fairly mild cam that SHOULD have smooth lift rates, and thus should not make the valvetrain appreciably noisier than stock.
Depends on who ground the cam...
Depends on who ground the cam...
02-13-2021, 01:57 PM
#4
Turbo:
about 20-30 thousandths worn off the peak of #2 intake lobe and a rough patch on about 25-30% of the lifter roller. I was experiencing random misfires in cyl 2 at low rpms. Cam bearings were not removed, but they looked good from what I could see, and the journals on the old cam were flawless. 110,000 miles on the old cam.
Atsma:
It is a Comp Cams build cam, never had issues with them personally.
I have a 30 second video from the 2nd run. Can I upload here, or do I have to upload to YouTube and link?
casey
about 20-30 thousandths worn off the peak of #2 intake lobe and a rough patch on about 25-30% of the lifter roller. I was experiencing random misfires in cyl 2 at low rpms. Cam bearings were not removed, but they looked good from what I could see, and the journals on the old cam were flawless. 110,000 miles on the old cam.
Atsma:
It is a Comp Cams build cam, never had issues with them personally.
I have a 30 second video from the 2nd run. Can I upload here, or do I have to upload to YouTube and link?
casey
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02-14-2021, 03:22 AM
#8
Small update....
The Brian Tooley pushrod kit had a couple different sized pushrods in it. I missed this on the install. I was randomly re checking the lifter preload on a couple rockers and found this right away. I thought I was crazy or there was a lifter issue for a quick minute.....
Going to summit later today (weather permitting) to swap for a good set....
Casey
The Brian Tooley pushrod kit had a couple different sized pushrods in it. I missed this on the install. I was randomly re checking the lifter preload on a couple rockers and found this right away. I thought I was crazy or there was a lifter issue for a quick minute.....
Going to summit later today (weather permitting) to swap for a good set....
Casey
02-14-2021, 07:37 AM
#9
Why would you need shorter than stock pushrods? Stock length is 7.400 afaik. Only thing changed is cam and lifters right?
I thought the consensus was that the LS7 lifters worked best with preload in the .080 to .100 range. Maybe I've got that wrong, hopefully more knowledgeable guys will comment.
I would try running it with your old stock pushrods and see how it sounds before buying more.
I thought the consensus was that the LS7 lifters worked best with preload in the .080 to .100 range. Maybe I've got that wrong, hopefully more knowledgeable guys will comment.
I would try running it with your old stock pushrods and see how it sounds before buying more.
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G Atsma (02-14-2021)
02-14-2021, 12:02 PM
#10
I was surprised that shorter pushrods were needed as well! I will say one of the incorrect rods in the set was 7.4” and with the cam on base lobe it was opening the valve when set. These lifters were specifically designed for.05 preload. With the 7.35 I’m real close to .06.
Casey
Casey
02-17-2021, 11:05 AM
#11
About 6-8 inches of snow fell here in TX since my last post. Got the new set of push rods in and installed. The engine sounds much better. Cold start has a little rattle, but once warm the sewing machine is almost quiet!!
casey
casey
02-25-2021, 01:04 AM
#12
Update,
I have finished the install, and after a few days of not realizing I pinched an injector wire under the coil pack bracket, I am up and running well. There was definitely some valve train chatter due to incorrect sized pushrods in the BT kit. They were labeled for the size I needed (7.35") but a couple were not the correct physical size. With the help of PC Tuners, I have honed in my MAF tuning, and am beginning my VVE tables. This Comp XFI cam has a noticeable power boost in the mid to high range.
Thanks to those that helped!!
Casey
I have finished the install, and after a few days of not realizing I pinched an injector wire under the coil pack bracket, I am up and running well. There was definitely some valve train chatter due to incorrect sized pushrods in the BT kit. They were labeled for the size I needed (7.35") but a couple were not the correct physical size. With the help of PC Tuners, I have honed in my MAF tuning, and am beginning my VVE tables. This Comp XFI cam has a noticeable power boost in the mid to high range.
Thanks to those that helped!!
Casey