Re-assembled my LS2, now notice the timing chain slapping against the chain guard
04-29-2011, 09:34 AM
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Re-assembled my LS2, now notice the timing chain slapping against the chain guard Back story....
So about 1.5 years ago I went from a Magnacharger setup on my LS2, to a twin turbo setup. My engine had 21k miles and built 4L50E transmission, but at just 8 PSI it was making some good power and the transmission would not upshift. I didn’t realize at the time that my aftermarket torque converter was likely the problem due to not having it re-stalled after it was built for the Magnacharger setup, and the engine kept hitting the rev limiter at full throttle instead of up-shifting. We were adjusting some TCM and PCM settings (ie: making a bigger gap between the shift points and the rev limit than what was originally working before) and after a few more unsuccessful attempts to get the transmission to up-shift at full throttle I blew the top ring-lands of all 4 pistons on bank 1 of the motor.
Present Day. The engine has sat around on a stand since it blew until I recently replaced the 4 blown pistons with some used, low-mileage LS2 pistons. I never touched anything aside from the connecting rods and the pistons during this repair. The aftermarket camshaft that was already installed stayed in place, as well as the timing components, crankshaft, lifters, crank pulley, flywheel, etc. were never removed nor touched.
After simply removing, inspecting and reinstalling the 8 pistons (replacing the 4 damaged ones) and connecting rod I had rotated the motor and everything felt good, and there was no unusual noise to be heard. I installed the heads, torqued them down, then installed the valve-train components (pushrods, rockers). Once the top-end was all together, I rotated everything a few more times to check for bind or anything unusual…
The issue...
Now, only after installing the valve train, I heard a ticking coming from the timing area as I rotate the engine by the crank pulley bolt, just like I had done prior to installing the valve train. I removed the crank pulley, removed the timing cover, and then removed the oil pump. I noticed about 3/8” (give or take a touch) of slack on the timing chain. I did some research and found that up to ½” slack is common on NEW LS2 chains, and that this is perfectly normal, according to reading 8+ other threads on multiple websites/forums regarding LS2 timing chain slack.
So as you can see in the videos below, as I rotated the engine clockwise, using a breaker bar, the slack on the bank 2 side of the timing chain is tapping against the timing chain guide. The guide shows no sign of wear from the chain, so I don’t believe that the chain has previously been touching the guide, at least during normal operating speed of the engine prior to me blowing the 4 pistons.
Below are 3 different videos that I took of the chain intermittently touching the guide as I slowly rotate the engine:
http://www.youtube.com/watch?v=YdC9yh_7f3k
http://www.youtube.com/watch?v=3r23dHDYaUI
http://www.youtube.com/watch?v=EWnnOMF0_VQ
Now, please again keep in mind that this timing chain slack is common and within tolerance, and this chain and engine only have 21k miles on them. So replacing the timing chain with another OEM timing chain won’t get rid of the slack. Also please keep in mind that what is seen in these videos only happened after re-installing the heads and valve-train. I have my own hypothesis for what might be causing the chain to tap the guide when rotating it by hand, but before I speak I’d like to hear your guys’ opinions on what you think may be causing the chain to touch the guide, and if this is something to worry about or not, as well as how to resolve the issue if it should be a concern. Thanks a bunch in advance… I’d really appreciate some experienced input here!
So about 1.5 years ago I went from a Magnacharger setup on my LS2, to a twin turbo setup. My engine had 21k miles and built 4L50E transmission, but at just 8 PSI it was making some good power and the transmission would not upshift. I didn’t realize at the time that my aftermarket torque converter was likely the problem due to not having it re-stalled after it was built for the Magnacharger setup, and the engine kept hitting the rev limiter at full throttle instead of up-shifting. We were adjusting some TCM and PCM settings (ie: making a bigger gap between the shift points and the rev limit than what was originally working before) and after a few more unsuccessful attempts to get the transmission to up-shift at full throttle I blew the top ring-lands of all 4 pistons on bank 1 of the motor.
Present Day. The engine has sat around on a stand since it blew until I recently replaced the 4 blown pistons with some used, low-mileage LS2 pistons. I never touched anything aside from the connecting rods and the pistons during this repair. The aftermarket camshaft that was already installed stayed in place, as well as the timing components, crankshaft, lifters, crank pulley, flywheel, etc. were never removed nor touched.
After simply removing, inspecting and reinstalling the 8 pistons (replacing the 4 damaged ones) and connecting rod I had rotated the motor and everything felt good, and there was no unusual noise to be heard. I installed the heads, torqued them down, then installed the valve-train components (pushrods, rockers). Once the top-end was all together, I rotated everything a few more times to check for bind or anything unusual…
The issue...
Now, only after installing the valve train, I heard a ticking coming from the timing area as I rotate the engine by the crank pulley bolt, just like I had done prior to installing the valve train. I removed the crank pulley, removed the timing cover, and then removed the oil pump. I noticed about 3/8” (give or take a touch) of slack on the timing chain. I did some research and found that up to ½” slack is common on NEW LS2 chains, and that this is perfectly normal, according to reading 8+ other threads on multiple websites/forums regarding LS2 timing chain slack.
So as you can see in the videos below, as I rotated the engine clockwise, using a breaker bar, the slack on the bank 2 side of the timing chain is tapping against the timing chain guide. The guide shows no sign of wear from the chain, so I don’t believe that the chain has previously been touching the guide, at least during normal operating speed of the engine prior to me blowing the 4 pistons.
Below are 3 different videos that I took of the chain intermittently touching the guide as I slowly rotate the engine:
http://www.youtube.com/watch?v=YdC9yh_7f3k
http://www.youtube.com/watch?v=3r23dHDYaUI
http://www.youtube.com/watch?v=EWnnOMF0_VQ
Now, please again keep in mind that this timing chain slack is common and within tolerance, and this chain and engine only have 21k miles on them. So replacing the timing chain with another OEM timing chain won’t get rid of the slack. Also please keep in mind that what is seen in these videos only happened after re-installing the heads and valve-train. I have my own hypothesis for what might be causing the chain to tap the guide when rotating it by hand, but before I speak I’d like to hear your guys’ opinions on what you think may be causing the chain to touch the guide, and if this is something to worry about or not, as well as how to resolve the issue if it should be a concern. Thanks a bunch in advance… I’d really appreciate some experienced input here!
04-30-2011, 09:45 AM
#3
I just put my brand new C5R timing chain on my 416 build and I have the same Chain dampner. It is nice and tight on one side and a little loose on the other. That is normal, you want it tight on one side so it will align nice and stable going to the teeth of the crank sprocket since it is smaller. It will bang a little on the dampner going up to the cam sprocket but it will still keep it stable going up. That's what the dampner does. Now imagine how it would be WITHOUT one?
I would be more concerned of your build, you didn't get the new parts balanced? No honing? You just slapped 4 used pistons and rods? Did you Get the engine cleaned up to remove and possible metals in the galleys?
That is what I would be more afraid of, uncleaned, unbalanced built engine.
I would be more concerned of your build, you didn't get the new parts balanced? No honing? You just slapped 4 used pistons and rods? Did you Get the engine cleaned up to remove and possible metals in the galleys?
That is what I would be more afraid of, uncleaned, unbalanced built engine.
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Jimbo1367 (10-31-2023)
05-02-2011, 06:37 AM
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Thanks a bunch for the input. Yeah everyone on LS1GTO.com had been saying, "get a new timing chain", but I had already ready all over about the LS2 chains having some slack, and of course a factory chain generally should have some slack. Not an awful lot, but some. So as far as the timing chain goes, I decided this weekend to leave it as it is and just drop the motor back in the car.
The parts that I put in were just used factory LS2 pistons, same as what I already had on the other bank of the engine. Nothing was balanced though. I kept the same connecting rods and just replaced the damaged factory pistons with used factory pistons. This was just a band-aid to get the motor running again instead of sitting around in the garage as it has been for the past 1.5+ years. If I had the money right now to do it right I would just have dropped $3k into building a forged assembly that would of course be balanced an whatnot... but that kind of extra money won't be around for a while with my bills :/
But I had honed all 8 cylinder walls and cleaned the block up really well before putting things back together.
The parts that I put in were just used factory LS2 pistons, same as what I already had on the other bank of the engine. Nothing was balanced though. I kept the same connecting rods and just replaced the damaged factory pistons with used factory pistons. This was just a band-aid to get the motor running again instead of sitting around in the garage as it has been for the past 1.5+ years. If I had the money right now to do it right I would just have dropped $3k into building a forged assembly that would of course be balanced an whatnot... but that kind of extra money won't be around for a while with my bills :/
But I had honed all 8 cylinder walls and cleaned the block up really well before putting things back together.
05-03-2011, 05:26 PM
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Litle88 is correct.
The point of the guard is to keep the chain from slapping around excessively on the slack side. Now if you had a smooth motion when you turned it over you will notice it wouldn't hit.
The only times the chain should hit the piece are when there is slack from acceleration or deceleration of RPMs.
What you see is perfectly normal. They make another variation and it's for the LS3, it looks to be spring loaded.
The point of the guard is to keep the chain from slapping around excessively on the slack side. Now if you had a smooth motion when you turned it over you will notice it wouldn't hit.
The only times the chain should hit the piece are when there is slack from acceleration or deceleration of RPMs.
What you see is perfectly normal. They make another variation and it's for the LS3, it looks to be spring loaded.
10-30-2023, 10:20 PM
#6
Hate to bump this ancient thread but I believe I’m having the same issue as this guy with the chain slapping the passenger side of the damper as I rotate the engine clockwise from the balancer bolt.
I just want to confirm that this is normal? Also does anybody have a link to the videos? It looks like they don’t work anymore.
I just want to confirm that this is normal? Also does anybody have a link to the videos? It looks like they don’t work anymore.
10-30-2023, 10:33 PM
#7
TECH Senior Member
If you're getting audible slap from just turning it over slowly by hand, you likely need a new chain.
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10-31-2023, 11:23 AM
#8
10-31-2023, 12:13 PM
#9
TECH Senior Member
What type of tensioner was in the LS3? Pretty sure they use the mechanical tensioner along the left side as you're looking at it.
10-31-2023, 12:38 PM
#10
10-31-2023, 07:20 PM
#11
ModSquad
iTrader: (6)
Show us a pic please of the slack. A decent amount of slack is perfectly normal.
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1FastBrick (10-31-2023)
10-31-2023, 09:33 PM
#12
https://ls1tech.com/forums/generatio...er-normal.html
Do they work for you?
