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Ecotech/l67 engine noise(valve train) magnified by extractors?

vsl67

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I have noticed ever since I have my L67 that it has engine noise like a metalic rumble coming from the engine especially when you are in a shed or near concrete road barriers,the sound is especially noticeable near the lower rear guard where the extractor connects to the exhaust ,I have also noticed this sound on na cars awell
So does the extractors manify valve train noise compared to stock headers? and has anyone else ever noticed this ?
 

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take off your rocker cover on that side and check to make sure your rocker bolts arent loose
 
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Yeah could just be exhaust noise or a leak?
Could be something not quite right inside the engine. Balance shaft bearing(s), supercharger bearings/rotors rubbing? Loose valve gear/rockers ? :eek:

Could use a 500-1000mm length of hose, poke it around the engine and listen - careful not to get caught in the drive belts, exhaust or ignition leads!!
Or take it to a mechanic to get a second opinion ;)
 

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My old ecotec had the same noise when I fitted extractors, and my L67 has it as well (and it is even worse the my old ecotec).
 

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Westerlybreeze has nailed it. i say it's the balance shaft bearings. i had a very similar noise in my VN and it turned out to be the rear bearing on the balance shaft. noise went away when i ripped it out.

using the poor man's stethoscope (ear muffs and long screw driver) put the end of the screw driver around the back of the block, right in the middle of the valley and listen (engine running of course)
 

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I'd say its just the noise through the extractors and pipes. Thats if it's like a light russling/ tapping sound

Stock manifolds are thick cast iron, and the stock y pipe is (i believe) double wall tube so it supresses a fair bit of noise. If you have extractors AND 100 cell stainless cats like i have, i should hear it. sounds like it's leaking though its perfectly sealed up, but its just the pulses through the pipes.
 
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Headers/extractors

Sweet! nothing to worry about.. something to look forward to! :rockon:
 

vsl67

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Thomas 1 and Ruf 231 have pretty well described what I was talking about ,I have rebuilt the super a couple of times ,and have replaced the standard rockers with roller rockers and I cannot get rid of the sound also I have done the rubber tube in the ear thing all over the motor and supercharger with no luck but interestingly I do have stainless cats as mentioned above and can only pin the noise down at the join from the extractor to the exhaust ,Im just glad just glad Im not the only one to have noticed this

But Im curious about the balance shaft bearings now
 

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the front bearing is a deep groove roller bearing and the rear bearing is a needle roller type. before i pulled mine out i put a dial gauge on it and everything came up within the tolerance measurements from the gregories manual. couldn't find anything wrong with it visually either. so i don't think it will ever fail, just possibly noisy
 
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