Does pushrod length affect lift?
07-02-2012, 10:30 PM
#1
Does pushrod length affect lift? Ok this is a stupid question lol, but I can't get it out of my head. I remember reading somewhere that if you don't put long enuf pushrods in when you put in a cam with a smaller base circle you don't see the full lift of the cam... This doesn't make sense to me thought because you have to torque your nut down either way so to me there should be now way the length affects full lift?
07-03-2012, 12:11 AM
#2
If you run too short of a pushrod, to the point you have no preload on the lifter, it can give you less lift. Same goes for too long. You will bottom out the plunger and the valves will hang open.
Too long or too short, You will have other problems before you notice the effects of the variation in lift.
Too long or too short, You will have other problems before you notice the effects of the variation in lift.
07-03-2012, 12:14 AM
#3
If you run too short of a pushrod, to the point you have no preload on the lifter, it can give you less lift. Same goes for too long. You will bottom out the plunger and the valves will hang open.
Too long or too short, You will have other problems before you notice the effects of the variation in lift.
Too long or too short, You will have other problems before you notice the effects of the variation in lift.
07-03-2012, 01:33 AM
#7
I would think they both determine preload? If you didn't put any torque on it there would be zero preload. So if you torqued to 24 ft lbs you would be closer to stock preload again. Not at all saying this is the right way to do it, but sounds like it might work to me
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07-03-2012, 07:13 AM
#8
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as for your original question having a pr that is shorter than the distance from the cup of the lifter to the cup of the rocker will reduce lift. it will also be VERY loud and chew up parts quickly. having a pr that is way too long to the point it bottoms out the lifter will move the valve off the seat before the cam lobe even moves the lifter. this is adding lift to the valve but it will be very obvious if this is the case. due to the valves being open when they shouldn't be it won't run very well(if at all) and won't make power either.
07-03-2012, 08:05 AM
#9
You are right. I am aware that running looser preload will quiet it down, but for argument sake, I left that out to keep from confusing the thread.
However, generally speaking, it is not good to run such low preload as it can cause more problems than it is worth.
However, generally speaking, it is not good to run such low preload as it can cause more problems than it is worth.
07-03-2012, 02:08 PM
#16
Ok so i shuld or should not run stock pushrods with the hot cam? I know they will fbe fine as far as strength goes, but is the length going to be ok? Idk how much smaller base cir le on the cam is?
Main question here is will stockers work with the hot cam?
Main question here is will stockers work with the hot cam?
07-03-2012, 02:24 PM
#17
I would be more worried about the quality. The stock pushrods are not good and I would bet if you roll yours across a perfectly flat surface you find at least 1 that is already bent.
