Sewing Machine Noise???????? Help
Thread Starter
Joined: Feb 2004
Posts: 1,131
Likes: 4
From: Franklin MASS
Sewing Machine Noise???????? Help Damn, I have heard about the sewing machine noise when installing a cam/heads...but this is loud!!!!! It almost sounds like a knocking. Cam specs are in my sig.....I kept the stock lifters, timing chain, and just put the stock push rods back in. Can anyone tell me if this is normal to hear this much noise coming from the engine bay????? It almost sounds like a knocking noise. I havent driven the car too much yet, just a couple trips around the block...it pulls like crazy though....I have a friend that tuned it a little for me. Dyno tune coming on Sat......any advise is very welcome, thanks in advance.....
Rob
Rob
Originally Posted by SSDude
It is normal if your car is not properly tuned. When your car is properly tuned it will not sound like a Singer Sewing machine.
The sewing machine noise is a byproduct of the mechanical acceleration of the valves in their guides, and the springs, the rockers, and everything else that makes up the valvetrain. It is because of the faster ramp rates and higher lifts in conjunction with heavier springs associated with aftermarket cams.
While a proper tune will make a world of difference in drivability and idle quality, it will have no effect on the sewing machine sound as the physincal mechanics of the way eyerything works remain unchanged.
I found that after a few thousand miles the sewing machine noise was less pronounced. I also found that using germnan castrol (possibly other thicker oils too) will quiet down valvetrain noise, although my cold piston slap is more pronounced now.
You could also have bent pushrods since they are stock. Not that you bent them now but they could have been bent before (slightly) and you not notice it until now. Stock lifter will also make a little more noise.
Thread Starter
Joined: Feb 2004
Posts: 1,131
Likes: 4
From: Franklin MASS
Well before I fired it the first time, I had chromolly pushrods in there from TR. Last night I changed them back to the stock ones, just to see if that would quiet it down a little.....
Oh ok I see. Well different people have different tolerances for different noises. Your car may be just like everyone else's and you just have a low tolerance. I'd take a try at a different oil. That could help you out. I'd pm PATMAN, he knows what to recommend.
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Please, please put the chrome moly pushrods back in. The stockers can bend like spagetti under the spring/ramp load of a cam like that. Not that it will cure your sewing machine noise, but it will give you full power.
How is your oil pressure at idle? That could be a potential problem if low.
How is your oil pressure at idle? That could be a potential problem if low.
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2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
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From: Gainesville, Denton TX
Originally Posted by Patrick G
Please, please put the chrome moly pushrods back in. The stockers can bend like spagetti under the spring/ramp load of a cam like that. Not that it will cure your sewing machine noise, but it will give you full power.
How is your oil pressure at idle? That could be a potential problem if low.
How is your oil pressure at idle? That could be a potential problem if low.
can i ask why you didnt replace the lifters while you had the heads off? for that little amount of money, its great insurance.
those stock Prods will look like a sippie straw if you continue to run them.
Get that 10mm and 8mm socket out now...
Thread Starter
Joined: Feb 2004
Posts: 1,131
Likes: 4
From: Franklin MASS
Got home last night, ordered a set of lifters from Comp, they will be here on Thursday.....time to start breaking down the motor again....
Patrick, my oil pressure is good at an idle. I never had a problem with that, even when it was stock. I did however put a ported LS6 oil pump in there though.....
Patrick, my oil pressure is good at an idle. I never had a problem with that, even when it was stock. I did however put a ported LS6 oil pump in there though.....
Not that you aren't experiencing a problem like those mentioned here and in other posts, but I have replaced everything, including a new shortblock, and have tried many different combinations of pushrod sizes, rockers, and lifters (although I didn't jump into adjustable rockers + Comp R's); and still have the the sewing machine noise. At this point I can say with all confidence that it is indeed a function of the various components of the valvetrain, most significantly, the XER lobes, dual springs, and larger valves. I have made up my mind that I have to live with it...
Thread Starter
Joined: Feb 2004
Posts: 1,131
Likes: 4
From: Franklin MASS
I still have the sewing machine noise, due to 921 springs...however, its knocking a bit too....and everything is tight (rockers) the only thing that it can be is the lifters...so the new ones will be here tomorrow....starting the teardown now.....will keep you posted....
Thanks everyone for your help..
Rob
Thanks everyone for your help..
Rob
