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Discussion Starter · #5 ·
im building a bigger engine for the beetle and thought i might as well get some lightweight ones as its all in pieces. i knew they added the horses but that was the only reason i got some. dont suppose anyone has got a sound clip? anything like the rally cars? although most of that is off the short gear box i suppose.
 

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Ive used the cb ones and when it was first started for the run in i was really shocked by how loud they were but like them now, its funny when someone asks why does your engine whine is it faulty i just say yes and enjoy the shocked look on there face when i take them out for a spin in it

heres what an engine sounds like with straight cuts

http://videos.streetfire.net/video/60f5c3b8-530a-45b9-9696-98b8010e3a0b.htm
 

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Helical gears apply axial load on the cam (i.e. the cam is being pushed length ways down the case), this is why we use double thrust bearing on performance motors. If you fit a bigger cam and heavy duty springs the harder it is for the cam to rotate so in turn the axial load increases (the cam is pushed harder length ways down the case as it is rotated).

Straight cut gears eliminates this axial load, reduces thrust-bearing wear and restores the power loss caused by this axial load that helical gears put on to the cam.

The reason helical gears are quiet is because they glide together as they rotate. The more back lash in the straight cuts the noisier they will be, I always use CB straights cut, they are good quality and usually quite quiet.. If you want very load straight cuts buy cheep ones.

Hope that makes sense….
 

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Helical gears apply axial load on the cam (i.e. the cam is being pushed length ways down the case), this is why we use double thrust bearing on performance motors. If you fit a bigger cam and heavy duty springs the harder it is for the cam to rotate so in turn the axial load increases (the cam is pushed harder length ways down the case as it is rotated).

Straight cut gears eliminates this axial load, reduces thrust-bearing wear and restores the power loss caused by this axial load that helical gears put on to the cam.

The reason helical gears are quiet is because they glide together as they rotate. The more back lash in the straight cuts the noisier they will be, I always use CB straights cut, they are good quality and usually quite quiet.. If you want very load straight cuts buy cheep ones.

Hope that makes sense….
Great explanation. About the only thing I'd add is that straight cuts really become important when you are running huge spring pressure like from K800 springs, etc... In most applications you don't really need straight cuts.

I can remember the day when only fast cars ran straight cuts...:rolleyes:
 

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Great explanation. About the only thing I'd add is that straight cuts really become important when you are running huge spring pressure like from K800 springs, etc... In most applications you don't really need straight cuts.

I can remember the day when only fast cars ran straight cuts...:rolleyes:
And another thing.. straight cuts will wear out quicker than helical gears. But not sure what the actual life expectancy of straightcuts actually is...
 
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