Roller cam - radius of curvature

[pastry_chef]

Reading about limits of roller cam design I see "radius of curvature" noted.
Larger journal cam cores can tolerate more aggressive lift curves.

What is the standard radius of curvature limit for a standard SBC core?

Thanks

[CamKing]

If you're talking about the negative radius(inverse radius) on the flanks of the lobes, that's limited by the radius of the grinding wheel used to machine it.
In most cases, 9"
In our case, 2"

[user-29956]

An inverse radius cam is like having your cake and eating it too!!!!!

[pastry_chef]

If you're talking about the negative radius(inverse radius) on the flanks of the lobes, that's limited by the radius of the grinding wheel used to machine it.
In most cases, 9"
In our case, 2"

Thanks Mike.

To clarify your grinding wheel radius 2 inches? this allows for a 2 inch minimum radius of curvature?

[CamKing]

correct

[ingram]

The diameter of the roller wheel used will also affect the radius of curvature in the design process.

[pastry_chef]

Thanks guys,

[CamKing]

If you're talking about the negative radius(inverse radius) on the flanks of the lobes, that's limited by the radius of the grinding wheel used to machine it.
In most cases, 9"
In our case, 2"

Thanks Mike.

To clarify your grinding wheel radius 2 inches? this allows for a 2 inch minimum radius of curvature?

BTW, we charge more if we have to use the 2" radius. If it's above 2.5", it's our standard price.

[MadBill]

If it's not proprietary Mike, what percentage of your catalog vs. custom roller lobes have <2.5" negative radius flanks? (And I probably shouldn't even ask about the resulting maximum pressure angles?)

[CamKing]

If it's not proprietary Mike, what percentage of your catalog vs. custom roller lobes have <2.5" negative radius flanks? (And I probably shouldn't even ask about the resulting maximum pressure angles?)

Almost all my roller designs are above 2.5" radius. That's the normal small wheel radius for the Berco.
We built a 2" radius grinding attachment for a finger follower system, I was doing development on.
I've only had to use it a couple other times.

[Walter R. Malik]

If it's not proprietary Mike, what percentage of your catalog vs. custom roller lobes have <2.5" negative radius flanks? (And I probably shouldn't even ask about the resulting maximum pressure angles?)

Almost all my roller designs are above 2.5" radius. That's the normal small wheel radius for the Berco.
We built a 2" radius grinding attachment for a finger follower system, I was doing development on.
I've only had to use it a couple other times.

Mike, have you ever seen the inverse radius lobe profiles on the roller camshaft installed in a "Wills Sainte Claire" inline six cylinder OHC engine ...?
They look like figure 8's.

They seem to even have a smaller than a 2" radius on the flanks so, how do you suppose they manufactured them in mass production...?

This has puzzled me for years.

[Krooser]

If it's not proprietary Mike, what percentage of your catalog vs. custom roller lobes have <2.5" negative radius flanks? (And I probably shouldn't even ask about the resulting maximum pressure angles?)

Almost all my roller designs are above 2.5" radius. That's the normal small wheel radius for the Berco.
We built a 2" radius grinding attachment for a finger follower system, I was doing development on.
I've only had to use it a couple other times.

Mike, have you ever seen the inverse radius lobe profiles on the roller camshaft installed in a "Wills Sainte Claire" inline six cylinder OHC engine ...?
They look like figure 8's.

They seem to even have a smaller than a 2" radius on the flanks so, how do you suppose they manufactured them in mass production...?

This has puzzled me for years.

The WSC engines have amazed thousands of us over the years...

[CamKing]

If it's not proprietary Mike, what percentage of your catalog vs. custom roller lobes have <2.5" negative radius flanks? (And I probably shouldn't even ask about the resulting maximum pressure angles?)

Almost all my roller designs are above 2.5" radius. That's the normal small wheel radius for the Berco.
We built a 2" radius grinding attachment for a finger follower system, I was doing development on.
I've only had to use it a couple other times.

Don't think I've ever seen one.
The smallest inverse radius I've seen, was on one of those old 1/4 speed cams.