Tapping noise in fresh, built LS7
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Joined: May 2007
Posts: 12
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Tapping noise in fresh, built LS7 Here are the specs.
2002 trans am
new gm ls7 block
new comp r lifters set at .020" cold
new hydraulic cam
lunati 4" crank, from my old ls1 383
lunati pro billets, also from my old 383
new cp pistons, total seal rings
new afr 225 with their dual spring upgrade and ti retainers
new melling hi volume oil pump
new 2005 ls2 comp single chain
It has about 70 psi of oil pressure cold with 20w50
Upon crank up this motor has a tapping noise deep inside the motor. The motor has now been run for a total of about 30 minutes. The noise doesn't get any louder with rpm, but it taps faster with accel. The noise gets quieter during decel. I cut the oil filter and it looks fine, the pan is off and there isn't any metal. The cam is fine, the crank endplay is fine, rod side clearance is fine. The clearance from the block to rotating assy. is fine. The chain and oil pump clearance is fine. Any ideas?
Thanks in advance
2002 trans am
new gm ls7 block
new comp r lifters set at .020" cold
new hydraulic cam
lunati 4" crank, from my old ls1 383
lunati pro billets, also from my old 383
new cp pistons, total seal rings
new afr 225 with their dual spring upgrade and ti retainers
new melling hi volume oil pump
new 2005 ls2 comp single chain
It has about 70 psi of oil pressure cold with 20w50
Upon crank up this motor has a tapping noise deep inside the motor. The motor has now been run for a total of about 30 minutes. The noise doesn't get any louder with rpm, but it taps faster with accel. The noise gets quieter during decel. I cut the oil filter and it looks fine, the pan is off and there isn't any metal. The cam is fine, the crank endplay is fine, rod side clearance is fine. The clearance from the block to rotating assy. is fine. The chain and oil pump clearance is fine. Any ideas?
Thanks in advance
Thread Starter
Registered User
Joined: May 2007
Posts: 12
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Thanks guys, I checked all of that, everything is fine there, but please, keep them coming. It sounds just like your banging gum ***** together at a non-constant pace. I'm thinking lifters myself, but I wanted to be sure I thought of everything possible before I pull the motor out of the car and apart. I've never heard of a problem with comp-r lifters and I wasn't sure if maybe someone had run across a problem with the lifter bores on ls7 blocks.
Thread Starter
Registered User
Joined: May 2007
Posts: 12
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I wish, I put 5W30 in it and its even louder. Can y'all think of anything else? I guess the next step will be a trailered ride to the machine shop for a listen. Thats 2.5 hours away though so I'm hoping to find or think of something before having to do that.
Thanks for all of the input so far.
Thanks for all of the input so far.
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Joined: Feb 2006
Posts: 1,170
Likes: 1
From: Rockfield Kentucky
You say;
new comp r lifters set at .020" cold
new hydraulic cam
What do you mean "set at .020 cold" Is that how much pre load you have on the lifter. Certainly your not putting .020 lash on a Hyraulic cam....or are you?
How different was the base circle on the cam than the previous cam?
Did you change the pushrod length if the base circle changed, deck height etc?
Try more pre load on the lifter, say .060.
Robin
new comp r lifters set at .020" cold
new hydraulic cam
What do you mean "set at .020 cold" Is that how much pre load you have on the lifter. Certainly your not putting .020 lash on a Hyraulic cam....or are you?
How different was the base circle on the cam than the previous cam?
Did you change the pushrod length if the base circle changed, deck height etc?
Try more pre load on the lifter, say .060.
Robin
I agree with above, .020 pre load doesn't sound like enough for those lifters, the Morels on the other hand need .020 cold pre load. I would suggest shooting for .060 pre load as well.
Best Regards,
Adrian
Best Regards,
Adrian
Comp R lifter are very hard to setup, completely different pre load setting then the rest of the lifters available for LS1's. I would call comp or a reputable shop and get the correct preload needed for those lifter if you don't already have that information.
