as long as it's not close to the edge, centering the sweep is preferred.
running close to the edge can cause premature valve guide wear.
Camshafts and Compression
- Thread starter Valman
- Start date
-
running close to the edge can cause premature valve guide wear.
Correct. But, a narrow sweep that isn’t centered will be far easier on the guides than a wide, centered sweep.
The centered sweep deal is over rated. If the roller isn’t running off the edge of the valve and it’s .040 wide it won’t wear the guides.
Yeah and almost 100% of the time, when people complain about their rockers hitting the springs or retainers, it's because the rocker shafts need relocating, yet they will argue you into the ground. What's worse is, sometimes even more uninformed, ignorant people will chime in agreeing with them and arguing against. And HERE'S the thing. All you have to do is CALL MIKE and he will tell you FOR FREE how to check to see if you need shaft relocating shims. IT COSTS NOTHING to check and people still argue. Just ignorant as HELL.
Last edited:
TT5.9mag
Two atmospheres are better than one
Or grinding on a rocker.
No you dope, Turk, nothing to do with DV.
I am sure Mike is a good guy, but he can still be wrong....
Below comes from Part 2 Tech of the B3 racing website. I do not know how to link it. Second sentence, 3rd paragraph. If anybody can link it, that would be good.
There are three errors.
"A roller tip was added to the nose of the rocker & everyting changed. No longer was the geometric point of rotation at the contact area of the roller tip & the valve tip. It is at the centre of the roller axle & maintains that point throughout the whole lift range, which means the ratio stays constant as well.......This is entirely different than the 'shoe' type rocker...
[1] The ratio varies as the rocker sweeps across the tip. On the valve side, the lever is from the fulcrum pivot to the contact point of the roller on the valve tip, not fulcrum to roller axle. Smokey Yunick explains, below.
[2] The ratio does NOT stay constant because of the changing position of the roller tip contact point, relative to the fulcrum.
[3] A shoe rocker works exactly the same as a roller rocker. The shoe can be likened to a large diameter roller. There is less ratio change because of the almost flat contact area. If you look at the chart in post #178, you will see there is very little change in the adv v measured lift of the stamped rocker.
You can see the ratio changes in the chart below.
I am sure Mike is a good guy, but he can still be wrong....
Below comes from Part 2 Tech of the B3 racing website. I do not know how to link it. Second sentence, 3rd paragraph. If anybody can link it, that would be good.
There are three errors.
"A roller tip was added to the nose of the rocker & everyting changed. No longer was the geometric point of rotation at the contact area of the roller tip & the valve tip. It is at the centre of the roller axle & maintains that point throughout the whole lift range, which means the ratio stays constant as well.......This is entirely different than the 'shoe' type rocker...
[1] The ratio varies as the rocker sweeps across the tip. On the valve side, the lever is from the fulcrum pivot to the contact point of the roller on the valve tip, not fulcrum to roller axle. Smokey Yunick explains, below.
[2] The ratio does NOT stay constant because of the changing position of the roller tip contact point, relative to the fulcrum.
[3] A shoe rocker works exactly the same as a roller rocker. The shoe can be likened to a large diameter roller. There is less ratio change because of the almost flat contact area. If you look at the chart in post #178, you will see there is very little change in the adv v measured lift of the stamped rocker.
You can see the ratio changes in the chart below.
My understanding, the tip of the rocker, roller or sliding/ radius, travels through an arc so there’s always going to be some angularity between the contact point and the pivot point / axle of the rocker through its sweep. Like Smokey says there. The clue is in the name, rocker!
Of course it can be improved by having good valvetrain geometry.
Anyhow, I’ll try and break up the saltiness a bit! 
Found another tool I forgot I had, pushrod length checker! I set it for 7.500’’ then to 7.650’’. To me, the longer setting looks better, however I can get a 7.500’’ without going to a custom made rod.
I could get away with the 7.500’’, about 3-4 threads showing. 7.650’’ may be better but 2.5 times the price for rods. What do you guys think??
Found another tool I forgot I had, pushrod length checker! I set it for 7.500’’ then to 7.650’’. To me, the longer setting looks better, however I can get a 7.500’’ without going to a custom made rod.
I could get away with the 7.500’’, about 3-4 threads showing. 7.650’’ may be better but 2.5 times the price for rods. What do you guys think??
Lol
WTF? Everyone KNOWS the ratio changes with lift.
It also changes with the placement of the shafts.
He’s not wrong. You can’t grasp what he’s saying.
I want the valve moving off the seat as fast as possible and I want the valve hanging around max lift the longest. Why you ask?
Because there isn’t a cylinder head in existence that flows as well at .100 lift as it does at max lift.
Think it through.
Mike isn’t wrong. If you’d take down your DV alter and think more you wouldn’t say stupid **** like you do above.
Certainly Mike can be wrong. So can I. At some point you need to learn you and DV can be wrong. A lot.
Last edited:
madmax2
Well-Known Member
Hi
I have a 404A1LUN solid cam on my 10:1 RC 418 stroker, it's a small cam... but not that small.
It's the replacement for the solid MP .528" 284º 241º
I love these cams
I have a 404A1LUN solid cam on my 10:1 RC 418 stroker, it's a small cam... but not that small.
It's the replacement for the solid MP .528" 284º 241º
I love these cams
Where did DV place in that cam shootout again? hmmmmmm
Last edited:
gzig5
Well-Known Member
I don’t think the 7.5 looks that bad but not easy to tell from the pic how much room there is through the sweep on both of them. Longer one looks like the cup could be close to touching on the shaft side?Anyhow, I’ll try and break up the saltiness a bit!
Found another tool I forgot I had, pushrod length checker! I set it for 7.500’’ then to 7.650’’. To me, the longer setting looks better, however I can get a 7.500’’ without going to a custom made rod.
I could get away with the 7.500’’, about 3-4 threads showing. 7.650’’ may be better but 2.5 times the price for rods. What do you guys think??
View attachment 1716369269
View attachment 1716369270
The photos not that great I know, the 7.650’’ may be slightly long. There is some clearance around the adjuster.
I might just go for the 7.500’’ rod.
TT5.9mag
Two atmospheres are better than one
The effective length of a shoe type rocker changes with the sweep, and point of contact. The effective length of a roller tip rocker does not change with the sweep, point of contact. They do not act the same.
Wrong,
They do act the same. What differs is the percentage difference. Bob Bolles, the Technical Editor of Circle Track magazine did an in-depth article on Crane's quick lift rockers & rockers in general.
[1] Crane does not believe in the minimum width pattern on the valve tip at the mid lift point. Many others do not believe in it either. See the first pic. Crane goes for the rocker tip centered at full lift, which minimises side loading of the valve stem/valve guide.
[2] The next two pics show how the ratio changes during operation. To claim that the ratio remains constant as a bold statement in post #205 is just wrong & can only be interpreted in one way: the words say it all.
[3] And the prod side of the rocker? Everybody worries about the roller centered on the valve tip but in Post #178 you can see the valve lift changed by 0.029" by changing prods.
They do act the same. What differs is the percentage difference. Bob Bolles, the Technical Editor of Circle Track magazine did an in-depth article on Crane's quick lift rockers & rockers in general.
[1] Crane does not believe in the minimum width pattern on the valve tip at the mid lift point. Many others do not believe in it either. See the first pic. Crane goes for the rocker tip centered at full lift, which minimises side loading of the valve stem/valve guide.
[2] The next two pics show how the ratio changes during operation. To claim that the ratio remains constant as a bold statement in post #205 is just wrong & can only be interpreted in one way: the words say it all.
[3] And the prod side of the rocker? Everybody worries about the roller centered on the valve tip but in Post #178 you can see the valve lift changed by 0.029" by changing prods.
I shoot for the roller "a little outside" of center of the valve tip with the valve closed. That way, it will be "a little inside" of center of the valve tip when the valve is open. I don't give a chit who says what. That's how I measure for pushrods.
A .150 difference is too much. Looks to me like a 7.600 is what you want.
If you want to do it how Chrysler says, set the adjuster at 9/32 protrusion and make the pushrods that length minus valve lash.
That is the correct way to do it.
Yup
I just watched Kieth Dorton on video doing rocket set up.
He had the sweep at .040.
It’s not hard to understand.
Are you saying the effective length of a roller tip rocker does not change as the rocker moves from a valve closed position to a valve open position?
TT5.9mag
Two atmospheres are better than one
Bewy don't read that , he still thinks the roller rolls with spring pressure throughout the cycle
TT5.9mag
Two atmospheres are better than one
What’s being missed is the whole reason for correcting the geometry on a shaft rocker system. The shaft (fulcrum) location. Moving the shaft to the correct location minimizes sweep across the valve tip and keeps the effective length of the roller rocker arm consistent.
-
Similar threads
