Tapping noise in fresh, built LS7
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Tapping noise in fresh, built LS7 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
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
were the lifters brand new? I have a little bit of lifter tick as well. Try changing your oil and adding in a qt of the Lucas SYNTHETIC oil stabilizer. Ive had good luck with it.
The synthetic stabilizer is a little expensive, but if you've got an LS7, then I'd say its worth it.
Also, did you do a LS7 cam or something big? Pushrod length? Are they straight? Are your rocker arms over/under torqued?
Theres quite a few things. Start with the basics meng.
Also, check the gapping on your plugs if you havent.
The synthetic stabilizer is a little expensive, but if you've got an LS7, then I'd say its worth it.
Also, did you do a LS7 cam or something big? Pushrod length? Are they straight? Are your rocker arms over/under torqued?
Theres quite a few things. Start with the basics meng.
Also, check the gapping on your plugs if you havent.
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Thanks Gregg, the lifters are new and the plugs are gapped and indexed and it has a big cam. The sound isn't under the valve covers, its deeeeep in the motor. The rocker arms are stock, torqued to spec, and the pushrod length is correct. Can you think of anything else? Thanks
Why are you running such thick oil? I'm hoping you live in the middle of the desert. Does the ticking go away as it gets warmer? BTW, comp r's seem to be a royal PITA unless you get them set up perfectly. I would have suggested LS7 lifters or a set of Comp OE replacements.
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From: Cincinnati, Ohio
Her is my story. I have an LS7 short block. It was originally built with JE center pin pistons. It had a knocking/tapping sound that is best described as "sounds like a diesel". It would go almost dead quiet when decellerating. I first thought it might be in the valvetrain and adjusted the valve several times. I even ran it without the valve covers and put a stethescope on the rocker to rule out the valvetrain. This engine made so much noise it sounded like it would fly apart if I would have gotten into it. My car is a street car I can't tolerate a shitty sounding motor. The builder had me pull out the engine and bring it to them so they could run it on an engine dyno. They tried to convince me that it was the normal sound of forged pistons. Long story short They agreed to replace the pistons with the type I had in my previous motor which were Diamond offset pin Teflon coated. The engine is sounds perfect now. The reason they go with offset pins is to alleviate the noise.
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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...I hope your wrong Vert!?!? 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.
This might be a stupid suggestion but did you check to make sure the windage tray is spaced out correctly? I know that if it is not spaced out correctly you will definately hear a pronounced tapping noise.
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Your right Greg, but in this case its less of a tick and more of a sound you would get if you knocked on a door. Vert may very well be on to something, I just hope thats not it, but what I'm hoping to do is have thought and checked everything before this motor and all of the nitrous plumbing associated wiring etc. has to come apart.
Keep em coming, It looks like I'll be heading out of town with it Friday night otherwise.
Thanks again.
Keep em coming, It looks like I'll be heading out of town with it Friday night otherwise.
Thanks again.
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Yeah King, checked that too, and again when the pan went back on. I'm not going to take anything as stupid or trivial because everybody knows its sometimes the smallest crap that run you around in circles the most. I hope its something I overlooked, I hope its simple and stupid, believe me.
