Ever use longer rods?
02-11-2008, 08:09 AM
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Ever use longer rods? Im currently installing a TSP TqV2 cam which has lift of about .100" greater than stock.
its my understanding that this lift comes from a smaller base circle, so my question is, if the base circle is smaller for this cam, shouldnt I need a longer rod to keep the same geometry as the stock valvetrain? I currently have 7.400" comp rods for the install, but it makes sense to me to make them a little longer.
so what gives?
its my understanding that this lift comes from a smaller base circle, so my question is, if the base circle is smaller for this cam, shouldnt I need a longer rod to keep the same geometry as the stock valvetrain? I currently have 7.400" comp rods for the install, but it makes sense to me to make them a little longer.
so what gives?
02-11-2008, 08:17 AM
#2
eh....dont know exactly what to tell you; what you are saying makes sense and id probably agree with you on that.
more than anything, Id consider it kinda... irrevelent... because with any change in the valvetrain whether it be lifters, cam, rocker arms, or different valves id check the valvetrain geometry with an adjustable pushrod length checker. heck, at less than 50 bucks, you cant afford to live without it.
more than anything, Id consider it kinda... irrevelent... because with any change in the valvetrain whether it be lifters, cam, rocker arms, or different valves id check the valvetrain geometry with an adjustable pushrod length checker. heck, at less than 50 bucks, you cant afford to live without it.
02-11-2008, 10:07 AM
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im more curious as to what other people do. I was going to get one of those, but a buddy said that you need to use the stock length pushrods.
did you use stock length rods with your vengeance cam ?
did you use stock length rods with your vengeance cam ?
02-11-2008, 10:15 AM
#4
Stock pushrods are 7.38" I think, so you are .020" better already. Check the new base circle of the cam, but I bet you are going to need longer pushrods. If the base circle is not too defferent you could always mill your heads @.035"-.040"
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02-11-2008, 10:55 AM
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Yes you need longer pushrods. Thunder Racing's old 7.400" pr's were actually 7.430" (I don't know if that has changed or not) which is usually the amount of change of base circ on an aftermarket cam.
02-12-2008, 10:32 AM
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I just got off the phone with thunder racing. the guy there said that the base circle on almost all aftermarket cams is in the area of .005" smaller than stock, so this is not enough to justify a longer rod. They use the 7.400 on all of their aftermarket cam jobs, whether it be TR rods or COMPs
