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what causes the sewing machine sound with cams

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Old 04-04-2005, 01:04 PM
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Default what causes the sewing machine sound with cams

whats causes this sound with these motors, is it because its all alumnium and the sound escapes it mine has it with a 222/224 566/568 112 comp 1.75 ratio rr, and pp ls6 stage 2 heads, i could swear i can here the sound coming from underneath the car from the headers more than, from the motor it self
Old 04-04-2005, 01:46 PM
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Originally Posted by jason5
whats causes this sound with these motors, is it because its all alumnium and the sound escapes it mine has it with a 222/224 566/568 112 comp 1.75 ratio rr, and pp ls6 stage 2 heads, i could swear i can here the sound coming from underneath the car from the headers more than, from the motor it self
there is a reasong why around this parts of the woods we call a cam swap the collaps lifter mod. Did you get new lifters and/or new hardened pushrods, the stockers aren't all that great once a cam goes in.
Old 04-04-2005, 01:48 PM
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new comp oe 850 lifters, comp 7.400 pushrods
Old 04-04-2005, 02:00 PM
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well then in that case i would say if is not to lowed and the car makes power then just turn up the stereo. This cars do make a little more noise, and most of us have learned to leave with it.

edit did you torque them down to 22 ft pound of torque??
Old 04-04-2005, 02:07 PM
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Roller cams make some noise, especially the more agressive you get. I had a cam with .510 lift and 224/230 degrees duration at .050 Hydraulic roller in my iron block SBC in an 86 MCSS. It loped pretty good and I could hear the cam rolling in the block over the 2 chamber flowmasters (not the crappy F-body ones). The car was a little loud, but you could still hear the cam rolling. It should be a smooth constant sound that goes up with engine speed.
Old 04-04-2005, 02:12 PM
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as long as you didnt overtighten or undertighten the rocker arm bolts and everything seems to be functioning properly dont worry about it
Old 04-04-2005, 02:38 PM
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Originally Posted by jason5
what causes the sewing machine sound with cams?
whats causes this sound with these motors?
what do you associate the sound of the sewing machine to be? the needle moving back and forth... a oscillating sound.

when the valvetrain is upgraded, its louder.. more forces at work, more agressive (read: faster) spring movement, ect.... so you hear it.

it just happens that the shape of everything makes a noise that reminds people of a sewing machine....
Old 04-04-2005, 02:44 PM
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on a mildly related note, my grandma owns a arts and crafts center... and having heard sewing machines all my life, i dont think the LS1 sounds like one.... it has alot of valvetrain noise, yes, but not a sewing machine noise.
Old 04-04-2005, 03:01 PM
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I love the sounds because I know they mean that I have a much improved/upgraded valvetrain.
Old 04-04-2005, 03:06 PM
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Does anyone else think its most pronounced at like 2000 rpms? I think mine is the loudest around this area....something with the harmonics.
Old 04-04-2005, 03:09 PM
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not sure what sound you are hearing, but if you reinstalled the oil pump o ring on the oil pickup tube it could very well be pinched and or leaking which would create air bubbles in the oil which will get into the lifters and make the motor sound IMO like a sewing machine. No mild hudrolic cam should make valve slaping sounds. only high lift solid roller cars. my g5x3 made sewing machine sounds, check the dip stick, sure enough, bubles in the oil. got the o ring out, pinched it so hard it snipped itself in half. Once replaced, valve train was quiet again. So check that out. otherwise if theres no bubbles in the oil on your dipstick, then i guess just a noisy valvetrain for no reason.
Old 04-04-2005, 03:22 PM
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Originally Posted by Camaro_Zach
not sure what sound you are hearing, but if you reinstalled the oil pump o ring on the oil pickup tube it could very well be pinched and or leaking which would create air bubbles in the oil which will get into the lifters and make the motor sound IMO like a sewing machine. No mild hudrolic cam should make valve slaping sounds. only high lift solid roller cars. my g5x3 made sewing machine sounds, check the dip stick, sure enough, bubles in the oil. got the o ring out, pinched it so hard it snipped itself in half. Once replaced, valve train was quiet again. So check that out. otherwise if theres no bubbles in the oil on your dipstick, then i guess just a noisy valvetrain for no reason.

I guess we should clarify the sound. I didn't think he was talking about the sound of lifters colapsing due to air in the lifter. Just the sound of a roller cam running. When you had this problem, how loud was the "valve slapping sound" I would think that, this might even cause the engine to spit and pop.
Old 04-04-2005, 03:35 PM
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we did a set of comp OE replacement lifters on an X3 car and it made the lifter noise noticably quieter vs the cars we usually do the cams in that use stock lifters...
Old 04-04-2005, 03:36 PM
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I had that same cam in my old SS and it had the sewing machine sound to. I also had 918 springs. I'm not sure why some have it and some don't. I've heard cars with much bigger cams and that didn't have it.
Old 04-04-2005, 03:39 PM
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I think the ramp rates along with lift are the deciding factors. Like a TR224 will prob. have more valvetrain noise than a tsp 231/237 since the tr224 has much more aggressive lobe design.
Old 04-04-2005, 04:55 PM
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I have a similar cam and my motor is honestly quiter than stock w/ 7.4's and stockers.
How much preload are you putting on those lifters ?
Old 04-04-2005, 06:24 PM
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Originally Posted by luv2spd
I think the ramp rates along with lift are the deciding factors. Like a TR224 will prob. have more valvetrain noise than a tsp 231/237 since the tr224 has much more aggressive lobe design.
That's interesting, I have the 224 112 with 918s and it definitely makes the sewing machine sounds, but I didn't know that the TR224 had a more "aggressive lobe design." Could you explain exactly what that means?

Thanks.
Old 04-04-2005, 06:29 PM
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Originally Posted by luv2spd
Does anyone else think its most pronounced at like 2000 rpms? I think mine is the loudest around this area....something with the harmonics.
Yeah, mine is pretty loud from 2000 - 2200 rpm. I have the TR220-114.

I've heard the sound is due to the CC918 springs???
Old 04-04-2005, 06:43 PM
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"I have a similar cam and my motor is honestly quiter than stock w/ 7.4's and stockers.
How much preload are you putting on those lifters ?"





2 turns at zero lash
Old 04-04-2005, 06:48 PM
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Originally Posted by equandt
Yeah, mine is pretty loud from 2000 - 2200 rpm. I have the TR220-114.

I've heard the sound is due to the CC918 springs???
Could be, but I'm running Patriot Golds and have the same thing.


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