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Old 01-06-2022, 03:43 PM   #61
Frank Castros
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Default Re: Explain to me again, please

Despite the disagreements of the subject matter this discussion of Valvetrain Geometry and how it legally applies to the rules of Stock Eliminator is fascinating.
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Old 01-06-2022, 05:18 PM   #62
Stan Weiss
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Default Re: Explain to me again, please

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Darren,

The biggest contributor of failures is dissimilar materials, finishes, treatments, changes on the engine oil additives/composition and break-in process.

The camshaft lobes and lifter surfaces are high load contact areas, and although they may be considered highly polished contact areas, immersed or sprayed with oil, there is still some surface asperity or roughness and the reason why many engine blocks have enclosed camshaft tunnels and many enclose the camshaft tunnel area.

Flat tappet camshafts and flat tappet hydraulic and solid lifters, also need to have a specific taper on the lobe and lifter crown. I have seen too many aftermarket camshafts and lifters that have been ground without enough taper, preventing the lifter to rotate, especially with high pressure valve springs. Many of the ceramic flat tappet lifters that I have seen,do not have any taper on the crown, therefore, you have a very high contact area that eventually will wear, causing a catastrophic failure. When you have the proper taper, the engine will require a camshaft thrust plate or stop to control its movement. Nevertheless, when you have a thrust plate or stop, you also need to have the appropriate clearance because being too tight, will also prevent the rotation of the lifter.

Material compatibility between the camshaft and lifters is also a big source of failures and also the lack of Zinc and other oil additives are also a culprit. My preference of break in oils is Maxima or Joe Gibbs.

For roller cams, I recommend the use of a Calcium Sulfonate based grease or lubricant such as Lubriplate 130-AA Multi-Purpose Calcium Type Grease. Calcium Sulfonate based grease is designed for high contact areas and I apply it to the roller camshaft lobes only.

My understanding is the cam lobe does have a taper. The lifter bottom has a radius to it. The size of the radius depends on how the cam lobe has been ground. I believe from the factory Ford has uses a different size radius on their lifter bottom than GM does.

Stan
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Old 01-06-2022, 06:57 PM   #63
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Default Re: Explain to me again, please

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My understanding is the cam lobe does have a taper. The lifter bottom has a radius to it. The size of the radius depends on how the cam lobe has been ground. I believe from the factory Ford has uses a different size radius on their lifter bottom than GM does.

Stan
My bad. You are correct Stan.
The lobe taper has a taper across the face and the lifter faces are ground spherically with a crown in the center. Also, when the camshaft and lifters are installed, the lifters are offset by a small amount from the cam lobes.
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Old 01-06-2022, 07:10 PM   #64
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Default Re: Explain to me again, please

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Ceramic lifters failure seems to start the snowball rolling for engine destruction. We brake the cam in on a fixture, run it on a dyno, race it with break in oil and then the ceramic lets go and it’s back to square one.
Ceramic materials were never intended for the dynamics and type of surface contact of a camshaft lobe and lifter crown. Ceramics are polycrystalline materials joined together, in layman terms, all ceramics are multiple crystals joined and formed together.

Although they are used in high impact applications such as ballistic armor, ceramics are brittle and have poor impact strength. When ceramics are used as ballistic armor, they are also surrounded by or encased in Kevlar material and replaced after receiving an impact.
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Old 01-06-2022, 08:50 PM   #65
Mark Yacavone
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Default Re: Explain to me again, please

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Ceramic materials were never intended for the dynamics and type of surface contact of a camshaft lobe and lifter crown. Ceramics are polycrystalline materials joined together, in layman terms, all ceramics are multiple crystals joined and formed together.

Although they are used in high impact applications such as ballistic armor, ceramics are brittle and have poor impact strength. When ceramics are used as ballistic armor, they are also surrounded by or encased in Kevlar material and replaced after receiving an impact.
Never should have been allowed in Stock in the first place.. Remember, about the same time..We've got to stop the use of "space age " materials in PRO STOCK !
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Old 01-06-2022, 09:22 PM   #66
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Default Re: Explain to me again, please

As has been said by a few here already, limit valve spring pressure. While a flat tappet does impose some limits as to what a cam lobe designer can do. Some of these limits maybe lifted with a roller lifter. Then what happens when the next weak link shows up? Another rules change?

Stan
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Old 01-06-2022, 10:43 PM   #67
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Default Re: Explain to me again, please

We changed to solids in the LT1 car because the hydraulics we're getting tired. Went from 10-30 to 5-30 and had rockers coming loose. Car is no faster with solids... however..if we ever get it to the point we can win a heads up race. A zero weight will probably work a little better with solids.
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Old 01-07-2022, 12:22 AM   #68
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Default Re: Explain to me again, please

Concerning cam and lifter wear issues with flat tappet cams, I was looking at my old Isky Cams catalog, and they offered some special "Hardface overlay" application on the lobes, which were meant to be used with their "Chilled Iron" flat tappet lifters. My catalog is from the 80s, so no idea if Isky still offers this stuff, but curious if anybody has any experience with these, in either a Stocker type engine, or anything else.
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Old 01-07-2022, 08:15 AM   #69
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Default Re: Explain to me again, please

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Concerning cam and lifter wear issues with flat tappet cams, I was looking at my old Isky Cams catalog, and they offered some special "Hardface overlay" application on the lobes, which were meant to be used with their "Chilled Iron" flat tappet lifters. My catalog is from the 80s, so no idea if Isky still offers this stuff, but curious if anybody has any experience with these, in either a Stocker type engine, or anything else.
Rory,
Some NASCAR teams ran the Isky solids with the hard face overlay.

Also, although not mentioned often, Crower makes some great solid lifters with lots of options, including lightweight and billet steel lifters.
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Old 01-07-2022, 10:23 AM   #70
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Default Re: Explain to me again, please



I understand there's a big differences between a full race lifter and a street motor lifter BUT some of these suppliers are advertising M2 Tool Steel Lifters. They are made over seas. So we now have junk tool steel lifters floating around, too. Grrrrrr

Little change of subject. Has anyone pulled the puck off of a Schubeck? How is it attached? Thinking maybe I could take a set of old lifters and weld M2 tool steel to bottom and have grd, hardened and coated. .
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