As mentioned before I am currently trying to fight Nissan to get a new motor in my car (or atleast a new head). It burns coolant pretty badly and they do not want to cover it.
I was told it's not covered because I have removed my balance shafts in the motor. Does anybody know where I can find some documentation from Nissan stating that the balancer unit is for NVH vibrations ONLY? They tried to tell me that it was part of the balancing of the rotating assembly, which I know its not. I need some documentation stating how it is for NVH ONLY. I think it will help me fight them.
QR25DE Balancer Unit
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EZcheese15
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lessthanjakejohn
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an inline 4 cylinder with a 0 180 180 0 crank suffers from unbalanced secondary force, moment, and torque. the rule of thumb is, above 2.0 L, objectionable NVH levels may be experienced at certain resonant RPMs where the frequency of the engines second harmonic coincides with one of the damped natural frequencies of the body.
i could get more into this, but the balance shaft(s) design involves cancelling moments and centrifugal forces of all the rotating and reciprocating masses.
problems are pretty much limited to NVH, but i have heard some mitsu's have trouble with crank walk... although im not sure if it is directly related.
i could get more into this, but the balance shaft(s) design involves cancelling moments and centrifugal forces of all the rotating and reciprocating masses.
problems are pretty much limited to NVH, but i have heard some mitsu's have trouble with crank walk... although im not sure if it is directly related.
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Q45tech
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Balance shafts are tuned to avoid the crankshaft bearing from being beaten to death, however the engine bearings will probably last thru the warranty without the shaft.........will it last 250,000 miles probably not.............but then again the other 2.0/2.4 usuallly didn't either..
http://autozine.kyul.net/techn...2.htmh ... is...s.pdf
pages after 50 give you the mathematics for 4 cylinder.
http://autozine.kyul.net/techn...2.htmh ... is...s.pdf
pages after 50 give you the mathematics for 4 cylinder.
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lessthanjakejohn
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Eswift wrote:an inline 4 cylinder with a 0 180 180 0 crank suffers from unbalanced secondary force, moment, and torque. the rule of thumb is, above 2.0 L, objectionable NVH levels may be experienced at certain resonant RPMs where the frequency of the engines second harmonic coincides with one of the damped natural frequencies of the body.
i could get more into this, but the balance shaft(s) design involves cancelling moments and centrifugal forces of all the rotating and reciprocating masses.
problems are pretty much limited to NVH, but i have heard some mitsu's have trouble with crank walk... although im not sure if it is directly related.
Thanks, but what are NVH forces
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lessthanjakejohn
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Q45tech wrote:Balance shafts are tuned to avoid the crankshaft bearing from being beaten to death, however the engine bearings will probably last thru the warranty without the shaft.........will it last 250,000 miles probably not.............but then again the other 2.0/2.4 usuallly didn't either..
http://autozine.kyul.net/techn...2.htmh ... is...s.pdf
pages after 50 give you the mathematics for 4 cylinder.
thanks
What are the positive effects of removing these? Increased power availabe because the engine doesn't have to turn these shafts?
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maxnix
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And increased wear due to increased 2nd order harmonic stress peaks.lessthanjakejohn wrote:What are the positive effects of removing these? Increased power availabe because the engine doesn't have to turn these shafts?
It's ultimately more efficient to go to more cylinders. Then there was Porsche with that 3-liter four banger. Some old early 20th century 4-cylinder engines were large, but turned very slowly.
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