Custom roller rockers

[bakes]

A couple others and I have talking about getting a set of custom roller rockers made up to complete are upgraded valve trains . I was think of finding some one to machine some aluminum or chromemoly ones and swap in the rollers from are stockers. im looking for weight reduction and maybe a roller tip if possible .
How many would be into some thing like this ? and if you had any other ideas would be great.

[boost geek]

If anything, I'd like a roller tip. Our valves always seem to get pushed a bit on an angle.

[bakes]

Was looking at ford 4.6 v8 rocker looks close and the lifters. but haven't
found an alu. rocker.

[glhs875]

Was looking at ford 4.6 v8 rocker looks close and the lifters. but haven't
found an alu. rocker.

I like the larger than ours camshaft roller on a 4.6 rocker. A larger roller has some valve lift and duration changing capabilities while keeping the same camshaft. When I was doing measurements the larger roller was worth 9-deg of duration. And depending on where it is placed in the rocker arm (closer to the lifter) it could offer increased lift with added acceleration as well. Actually it would be sweet to have some choices between different roller sizes and placements to play around with between the intake and exhaust lobes.

[bakes]

I like the larger than ours camshaft roller on a 4.6 rocker. A larger roller has some valve lift and duration changing capabilities while keeping the same camshaft. When I was doing measurements the larger roller was worth 9-deg of duration. And depending on where it is placed in the rocker arm (closer to the lifter) it could offer increased lift with added acceleration as well. Actually it would sweet to have some choices between different roller sizes and placements to play around with between the intake and exhaust lobes.

That is what i was thinking too.

[OmniLuvr]

id like aluminum, could there be a possibility of getting different ratio? or some way to modify the location of the roller part that rides on the cam to change the geometry, or can this only be solved by a cam with a larger base circle?

[Reeves]

Interested.

[mock_glh]

... could there be a possibility of getting different ratio?

More than 1.74? That's already pretty big by some standards.

A larger roller would solve a few problems. You'd gain some acceleration and at the same time reduce side loading. This could also compensate for the reduced base circle on reground cams. Stock rockers could be modified for this.

[zin]

More than 1.74? That's already pretty big by some standards.

A larger roller would solve a few problems. You'd gain some acceleration and at the same time reduce side loading. This could also compensate for the reduced base circle on reground cams. Stock rockers could be modified for this.

+1

[Juggy]

count me in

[bakes]

Would roller tip add to much weight to the wrong end?

[badandy]

Interested if it had a roller tip

[Reeves]

Interested if it had a roller tip

Right.

[BadAssPerformance]

Instead of a roller tip could we ground a radius into the tip of the valvestem?

[Tim]

If you change the location of the roller that touches the cam you may change the rocker ratio, but you will also change the degree-in of the cam.

Think about it, the cam is now touching the roller in a different spot, it has to turn to a different spot to be at the same point on the lobe.

[zin]

If you change the location of the roller that touches the cam you may change the rocker ratio, but you will also change the degree-in of the cam.

Think about it, the cam is now touching the roller in a different spot, it has to turn to a different spot to be at the same point on the lobe.

I'm going to disagree. The ratio is a function of the pivot point vs the length of rocker contact points on either side of it, as in the SBC. In our case its all about the pivot point, closer to the cam the higher the ratio (and valve lift for a given cam lift), as well as the stress on the rocker and the acceleration of the valve, all other factors being the same. Normally the pivot point and tip are not something you can (or would want to) change, normally. Ours is a odd lot, the roller on the cam really needs to stay on the center-line, while the tip almost doesn't matter, assuming it's contact point is long enough to not slide off the valve tip at max lift, but if you want a different ratio, you'll have to change the pivot point...

The real problem as I see it is that the pivot point can't easily be changed. The only practical way I can see is to build new, mechanical lifters/adjusters with the pivot off-set one way or the other to increase or decrease the ratio. They would have to be indexed and not allowed to turn in their bores as well.

Mike

[86Shelby]

Ours is a odd lot, the roller on the cam really needs to stay on the center-line, while the tip almost doesn't matter, assuming it's contact point is long enough to not slide off the valve tip at max lift, but if you want a different ratio, you'll have to change the pivot point...

Maybe I'm not visualizing this the same. Why would the roller need to stay on the centerline? I'm looking at things like this:
Instead of having the rocker spaced like this: valve......roller....lifter
Space it like this: valve........roller..lifter It keeps the overall length the same, so there's no engineering one-off lifters, etc.

Higher ratio for higher lift and effectively more duration. It will change the cam timing quite a bit, but that's what adjustable gears are for.

[bakes]

Maybe I'm not visualizing this the same. Why would the roller need to stay on the centerline? I'm looking at things like this:
Instead of having the rocker spaced like this: valve......roller....lifter
Space it like this: valve........roller..lifter It keeps the overall length the same, so there's no engineering one-off lifters, etc.

Higher ratio for higher lift and effectively more duration. It will change the cam timing quite a bit, but that's what adjustable gears are for.

Ya but what about the guys already running higher lift cams they will mash the valve retainers in the valve guides

[Directconnection]

If you change the location of the roller that touches the cam you may change the rocker ratio, but you will also change the degree-in of the cam.

Think about it, the cam is now touching the roller in a different spot, it has to turn to a different spot to be at the same point on the lobe.

Exactly.... and if you change the diameter of the wheel, too. Then, you'll totally mess of your cam's profile and valve timing events and need a special designed cam just for the new rocker's geometries.

[zin]

Exactly.... and if you change the diameter of the wheel, too. Then, you'll totally mess of your cam's profile and valve timing events and need a special designed cam just for the new rocker's geometries.

I have to disagree, if I'm reading you right...

If the wheel is simply larger, it's effect would be limited to how quick the lobe reacts with the rocker, making the cam faster acting, but not changing the phasing as their respective contact points don't change, same for rocker ratio, so long as the center-lines of the roller/cam/lifter are the same, the ratio stays the same too.

I'll admit, a given cam with an aggressive ramp might require a redesign to be compatible (no metal parts crashing into each other), and definitely to maintain the valve action of that cam, due to the fact the roller will contact the ramp sooner and run up it quicker, effectively changing the duration a bit depending on how much larger the diameter of the roller is made. I haven't seen too many cams used in our engines who's ramps are aggressive enough to become unusable... Though they certainly would act "bigger".

Mike