Advance in cam
04-21-2010, 03:26 AM
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Advance in cam I asked a gm tech about advance ground into cams for the ls series motors. I have seen plenty of cams for sale w/ advance ground into them on this sight and the vast majority are going into motors that aren't new. My question is that he said a cam w/ advance ground in put in a motor that previously had no cam advance in it shifts the wear points of the rods (forget the exact wear points, feel free to tell me what those points are) and that motors he had seen this done to had rod knock within 10k miles (motors he talked about weren't necessarily ls motors). So what is the extent of the truth to this for older motors and ls series since I see plenty of cams w/ advance ground into them.
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04-21-2010, 08:40 PM
#2
I don't see how there is any correlation. The reason advance is ground in is because aftermarket cams tend to have more duration which makes bottom end power soft and the advance just brings the powerband in a bit sooner to make up for it.... My cam has 2* advance with 30K miles, a couple dozen track passes and countless WOT street pulls spinning 6500 and no ill efects....
The only thing close I can even think he is refering too is if a cam makes power too high in the RPM band the weak GM rod bolts will stretch after repeated high rpm spinning causing spun bearings usually... But advance has NOTHING to do with that....
The only thing close I can even think he is refering too is if a cam makes power too high in the RPM band the weak GM rod bolts will stretch after repeated high rpm spinning causing spun bearings usually... But advance has NOTHING to do with that....
04-21-2010, 09:29 PM
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I don't see how there is any correlation. The reason advance is ground in is because aftermarket cams tend to have more duration which makes bottom end power soft and the advance just brings the powerband in a bit sooner to make up for it.... My cam has 2* advance with 30K miles, a couple dozen track passes and countless WOT street pulls spinning 6500 and no ill efects....
The only thing close I can even think he is refering too is if a cam makes power too high in the RPM band the weak GM rod bolts will stretch after repeated high rpm spinning causing spun bearings usually... But advance has NOTHING to do with that....
The only thing close I can even think he is refering too is if a cam makes power too high in the RPM band the weak GM rod bolts will stretch after repeated high rpm spinning causing spun bearings usually... But advance has NOTHING to do with that....
GM tech 