440 power gains/ aluminum head advantages?
- Thread starter NoahSewal
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NoahSewal
Well-Known Member
got around to messing with the dart some more. been busy working on my firebird. got the pans welded in and seam sealed! i've ran into a problem tho on my dart. did they use a different length pushrod for mechanical lifters vs hydraulic on 440s? put the solid lifter in and it's way off the pushrod won't even seat in the lifter with the rocker rail all the way down. the lifter says it's for mopar and i believe it's stock lifter seat height. 1.630" seat height. do you think i could use an adjustable pushrod? max it out when it's on the lowest spot on the lobe and just make sure it doesn't adjust when i'm rotating engine?
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MomsDuster
Well-Known Member
I could be wrong, but couldn’t you just measure lift from the lifter itself when degreeing the cam?
Pretty good video here.
Pretty good video here.
PRH
Well-Known Member
Just degree the cam off the pushrod.
NoahSewal
Well-Known Member
i have ball end pushrods. how do i measure lift from pushrod without rockers on it? i'm wondering if i could just put the dial indicator on the top of the lifter and rotate the engine... hm. i took an old hydraulic lifter i had and tac welded the seat to the lifter and installed it but something has to be off because the rocker on that lobe has no play even at the very bottom of the cam lobe. can't move it side to side at all. like it's holding the valve open a little all the way around the lobe. there is no weld or splatter at all in the top of the lifter where the pushrod sits so i'm not sure how it could be like that. i might just try to tac weld another a try it to see if it works normal. all this fuss i might also just break down and buy a valve spring compressor for head on engine and change it out to the lightweight spring that came in my degree kit.
Put it on lifter down in the valley multiply by 1-1/2 there your lift. Or use a cupped pushrod, dowel, brake line, copper tubing, laying against the rocker shaft (keep it straight up and down) all measurement can be taken off the lifter. On what you made you’re getting into preload of lifter
Assuming a rocker will produce the lift from the stated ratio will lead to errors. Numerous factors such as prod length will affect the final ratio: ie lobe lift multiplied by the rocker ratio equals the valve lift. The ratio changes during the sweep of the rocker. Below are some rockers D. Vizard tested & as you can see the ratios are all over the place.
If you want accurate results, measure off the lifter....
If you want accurate results, measure off the lifter....
If I want to know the lift for that engine and rocker I’ll measure off retainer, but like you said all the rest measure off the lifter (use solid lifter)
PRH
Well-Known Member
get a piece of round stock a couple inches long.
Drill a hole in one end about 3/4” deep just big enough to slide over the pushrod.
On the other end just go in deep enough to make a divot for the indicator point to sit in.
That will give a good measuring place for the indicator.
Drill a hole in one end about 3/4” deep just big enough to slide over the pushrod.
On the other end just go in deep enough to make a divot for the indicator point to sit in.
That will give a good measuring place for the indicator.
PRH
Well-Known Member
Marathon cam degreeing session?
NoahSewal
Well-Known Member
lol basically. been pretty hot out and i've been trying to figure out how i'll degree it with my setup. i finally understood and got a consistent reading while degreeing. my intake lobe centerline is 110 degrees. recommend intake centerline for my cam is 105. is there a huge loss of power here being 5 degrees off? i'm not sure how much is too much but from what i've read .5 degrees tolerance is ideal.
NoahSewal
Well-Known Member
finally got consistent reading from intake centerline. i'm at 110 degrees and isky recommends 105. how much of a power loss am i having being 5 degrees off?
Five degrees 'off'. Off which way, advanced or retarded? I am always amazed at the time spent tinkering to get the cam exactly at some amount of adv or ret......for a cam that has not been used or tested & therefore no info where the best position [ position: whether it should be advanced or retarded & by how much ] would be to install it.
While a few degrees of advance is often used, the FACT is that if you want to find the optimum position, you have to put the engine on a dyno....& test at each position.
Generally [ with lots of exceptions ], advancing the cam can pick up a few hp at the low end....& retarding the cam will do the opposite; & may give a few more HP at the top end, especially if the cam was a bit small.
While a few degrees of advance is often used, the FACT is that if you want to find the optimum position, you have to put the engine on a dyno....& test at each position.
Generally [ with lots of exceptions ], advancing the cam can pick up a few hp at the low end....& retarding the cam will do the opposite; & may give a few more HP at the top end, especially if the cam was a bit small.
PRH
Well-Known Member
The cam being 5* retarded isn’t doing your combo any favors, but it’s not like that alone would explain the huge power loss you’re seeing.
Correct it to 104-105 c/l, button it back up and see what it’s like.
Correct it to 104-105 c/l, button it back up and see what it’s like.
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