REC Seminar content'

[RevTheory]

I guess having the best spring in the world doesn't do much good if the pushrod turns into a pole vault or a tuning fork.

I'm anxious to attend the REC as a spectator this year. David, are you dragging some spintron data to your lecture there? You always had a mountain of supporting data at both your Horsepower seminar and your head porting class so I'm betting spintron data would be interesting as hell, at least for me.

[CamKing]

Do you believe your cam designs are more stable and/or easier on the valve train than what you see with comparable-sized cams from your major competitors?

Yes, and years of testing has proven that, over and over.
If you compare one of my designs with a major competitor's cam, with the same lift, duration, and area, mine is much more stable, because the velocity at the lash point is lower, which makes the valve acceleration off the seat lower.

[BradH]

Do you believe your cam designs are more stable and/or easier on the valve train than what you see with comparable-sized cams from your major competitors?

Yes, and years of testing has proven that, over and over.
If you compare one of my designs with a major competitor's cam, with the same lift, duration, and area, mine is much more stable, because the velocity at the lash point is lower, which makes the valve acceleration off the seat lower.

That probably explains what I've seen when I mapped a couple of your solid roller lobes and compared them to another brand of solid roller cam.

My apology for derailing an already derailed thread...

[Stan Weiss]

Do you believe your cam designs are more stable and/or easier on the valve train than what you see with comparable-sized cams from your major competitors?

Yes, and years of testing has proven that, over and over.
If you compare one of my designs with a major competitor's cam, with the same lift, duration, and area, mine is much more stable, because the velocity at the lash point is lower, which makes the valve acceleration off the seat lower.

That probably explains what I've seen when I mapped a couple of your solid roller lobes and compared them to another brand of solid roller cam.

My apology for derailing an already derailed thread...

Since in an answer to me Mike talked about 1/4 degrees. Can I ask what you used to map his cams?

Stan

[BradH]

A degree wheel, a dial indicator, a block with bushed lifter bores, a timing chain set, lifters and some cams... oh, and a degree wheel pointer made from a wire coat hanger. The differences that I noted didn't require 1/4 degree accuracy to be apparent.

[Stan Weiss]

Mike,
I know that UDHarold even on a full symmetrical cam lobe would use asymmetrical lash ramps to reduce seating velocity. Do you look at RPM range and seating velocity when designing your lash ramps?

No.
My lash ramps are based on the velocity of the first 1/4 degree beyond the opening lash ramp, and the last 1/4 degree before the closing lash ramp.
I look at RPM range when designing the lobe profile(before adding the ramps), because the lobe profile is what dictates the seating velocity.
slowing down the closing lash ramp, without changing the velocity/acceleration leading to the lash ramp, wouldn't reduce seat bounce.

A degree wheel, a dial indicator, a block with bushed lifter bores, a timing chain set, lifters and some cams... oh, and a degree wheel pointer made from a wire coat hanger. The differences that I noted didn't require 1/4 degree accuracy to be apparent.

Brad,
What have you seen in the way of differences in seating velocity between Mike's cam and some others you have measured.

Stan

[David Vizard]

I guess having the best spring in the world doesn't do much good if the pushrod turns into a pole vault or a tuning fork.

I'm anxious to attend the REC as a spectator this year. David, are you dragging some spintron data to your lecture there? You always had a mountain of supporting data at both your Horsepower seminar and your head porting class so I'm betting spintron data would be interesting as hell, at least for me.

Rev,

I have got a lot of data from a two week Spintron test session that a big corporation generously paid for. Some was testing for their agenda but they generously covered mine as well. Got some good stuff that could well be unique within the industry.

DV

[David Vizard]

Do you believe your cam designs are more stable and/or easier on the valve train than what you see with comparable-sized cams from your major competitors?

Yes, and years of testing has proven that, over and over.
If you compare one of my designs with a major competitor's cam, with the same lift, duration, and area, mine is much more stable, because the velocity at the lash point is lower, which makes the valve acceleration off the seat lower.

I can vouch for that. Having used and dynoed about a dozen of Mikes cams I can say that the valve trains concerned have run to the desired RPM limits with a thoughtfully selected spring of far less poundage that would be expected.

DV

[David Vizard]

Guys,

For those who are wandering off the subject can we please return to materially relevant subjects or this thread will die a death in some lonely ST spot.

Thanks,
DV

[David Vizard]

Just to hopefully move in a direction relevant to my last post another important subject I will be dealing with is rockers and how your selection can be worth as much as 20 hp. I'm not speaking here of say, a 1.7 Vs 1.8 or the like, but a 1.8 Vs a 1.8.

In the case of the test I have in mind the difference was 18 hp. I am sure many of you would like to know why. Well it's a bit long to cover here but I will go into detail in my seminar.

DV

[Warp Speed]

Guys,

For those who are wandering off the subject can we please return to materially relevant subjects or this thread will die a death in some lonely ST spot.

Thanks,
DV

If you want to move the thread away from a technical direction, (which obviously wasn't the original intent) would it have been better for it to be posted in the general discussion section, instead of the engine tech section?

[BradH]

Do you believe your cam designs are more stable and/or easier on the valve train than what you see with comparable-sized cams from your major competitors?

Yes, and years of testing has proven that, over and over.
If you compare one of my designs with a major competitor's cam, with the same lift, duration, and area, mine is much more stable, because the velocity at the lash point is lower, which makes the valve acceleration off the seat lower.

That probably explains what I've seen when I mapped a couple of your solid roller lobes and compared them to another brand of solid roller cam.

Difference observed in JRC vs "other" cam profiles I found...

Lobes measured in block using .815"-wheel lifters. I checked seat duration at lash point, and SAE duration (.004" lobe lift above lash), then lobes were measured at .020, .050, .100, .200, .300, .400 and peak lobe lift. However, what I'm focusing on here are differences in the area of the ramps & seat durations.

COMP RX Endurance lobe 4309:
- Advertised as 298 at .020" / 265° at .050" / 183 at .200" / .433" lobe
- This particular cam was ground on their "B" master with a larger base circle

At lash point = 315
SAE duration for .018" lash (1.5 rr) = 307
.020 = 300
.050 = 266
.100 = 232
.200 = 184
...

JRC IR intake & exhaust lobes advertised as:
- 308° adv / 295 at .020" / 259° at .050" / 179 at .200" / .424" lobe
- 312° adv / 298 at .020" / 261° at .050" / 181 at .200" / .421" lobe

At lash point = 323 / 334
SAE duration for .016" lash (1.5 rr) = 307 / 311
.020 = 295 / 297
.050 = 261 / 263
.100 = 229 / 231
.200 = 180 / 182
...

*** If this info needs to be moved to a new/different thread, let me know ***

[Stan Weiss]

Yes, and years of testing has proven that, over and over.
If you compare one of my designs with a major competitor's cam, with the same lift, duration, and area, mine is much more stable, because the velocity at the lash point is lower, which makes the valve acceleration off the seat lower.

That probably explains what I've seen when I mapped a couple of your solid roller lobes and compared them to another brand of solid roller cam.

Difference observed in JRC vs "other" cam profiles I found...

Lobes measured in block using .815"-wheel lifters. I checked seat duration at lash point, and SAE duration (.004" lobe lift above lash), then lobes were measured at .020, .050, .100, .200, .300, .400 and peak lobe lift. However, what I'm focusing on here are differences in the area of the ramps & seat durations.

COMP RX Endurance lobe 4309:
- Advertised as 298 at .020" / 265° at .050" / 183 at .200" / .433" lobe
- This particular cam was ground on their "B" master with a larger base circle

At lash point = 315 <<<<<<
SAE duration for .018" lash (1.5 rr) = 307
.020 = 300
.050 = 266
.100 = 232
.200 = 184
...

JRC IR intake & exhaust lobes advertised as:
- 308° adv / 295 at .020" / 259° at .050" / 179 at .200" / .424" lobe
- 312° adv / 298 at .020" / 261° at .050" / 181 at .200" / .421" lobe

At lash point = 323 / 334 <<<<<<
SAE duration for .016" lash (1.5 rr) = 307 / 311
.020 = 295 / 297
.050 = 261 / 263
.100 = 229 / 231
.200 = 180 / 182
...

*** If this info needs to be moved to a new/different thread, let me know ***

Brad,
Thanks for the number. I am not sure what you mean by At lash point. Is there where the lifter moves off of the base center and the lash ramp starts and ends?

Stan

[CamKing]

. I am not sure what you mean by At lash point. Is there where the lifter moves off of the base center and the lash ramp starts and ends?

That should be what he's using. The actual hot lash settings.
Up until you reach that hot lash point, the valve, spring, and retainer have zero velocity, and zero acceleration. That first point of contact, where the valve starts to move will determine the initial acceleration rate of the valve, spring and retainer. When comparing my cams, to other designs, the velocity at that lash point is usually about 1/2 of what I see on other company's designs. This produces a much smaller acceleration spike for the valve, spring, and retainer.

[BradH]

Yes, I'm listing the duration points at both SAE (.006" valve lift) and "lash point" (the lift where the lash is reduced to zero on opening and begins to have clearance upon closing), at least as closely as I can get it from reading the dial indicator.

Lash --- 1.5 Lobe Lift --- 1.6 Lobe Lift
-------- SAE/(Lash point) - SAE/(Lash point)
.016" --- .0147"/(.0107") - .0137"/(.0100")
.018" --- .0160"/(.0120") - .0150"/(.0112")
.020" --- .0173"/(.0133") - .0162"/(.0125")
.022" --- .0187"/(.0147") - .0175"/(.0138")
.024" --- .0200"/(.0160") - .0187"/(.0150")
.026" --- .0213"/(.0173") - .0200"/(.0163")
.028" --- .0227"/(.0187") - .0212"/(.0175")

Example:
.018" lash at the valve w/ 1.5 rr --> .018"/1.5 = .012" lobe lift
SAE is .012" lobe lift + .004"* --> .016" lobe lift

* .006" valve lift / 1.5 rr = .004"