Rockwell test on cams and lifters

Old 07-29-2013, 02:52 PM
  #1  
zipper06
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Default Rockwell test on cams and lifters

As promised last month, when i went up to Ms. i would test several cams and lifters for hardness.
The first test was a 6 to 7 yr old Comp cams hydraulic flat tappet cam that went flat in my street El Camino on 3 lobes.

Tested 29/30 RC really soft in my opinion.

I then tested the lifters that were on the cam.

They tested 57/58 RC, not a problem i think.

I then tested a 13 Yr. old Bullit solid flat tappet cam, still good after a couple hundred passes on it.

It tested 34/35 RC a full 5 points harder than the newer Comp hydraulic cam.

I then tested a new never run set of solid flat tappets lifters

They tested 60/61 RC

I then tested a solid roller Comp Cams Cam

It tested 58 RC

I then tested a set of Comp Cams Extreme duty .180 offet solid rollers
lifters.

They tested 38/41 RC

I tested all the lifters on the body portion of the lifters

the Cam companys are saying the problem is with the lifters, I think that's BS, it's a cam core problem and they don't want to address the cam hardness problem, I doubt if they even have a Rockwell tester, ofcourse the like of Zinc in todays oils are a contributing factor also.
They are now putting oil holes in the solid flat tappet lifters for an extra fee, i think howards cams started this.

In conclusion they are using cheaper softer cam cores, and are not really intrested in solving the problems, but would rather sell hydraulic roller cams which cost as much as $700.00/$800.00.

JMO

Zip.
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Old 07-29-2013, 06:42 PM
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Swiley383
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I am glad you did that test. I have heard people give different options on this subject but never with real test data to back it up. Ten years or so ago a guy at the track told me he did not think cams were of the same material they once were. This was around the time a I started hearing about cam problems. Since then people have told me manufactures were using too much spring pressure among other things again good info thanks.
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Old 07-29-2013, 08:00 PM
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hink
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Default Re: Rockwell test on cams and lifters

Originally Posted by zipper06
As promised last month, when i went up to Ms. i would test several cams and lifters for hardness.
The first test was a 6 to 7 yr old Comp cams hydraulic flat tappet cam that went flat in my street El Camino on 3 lobes.

Tested 29/30 RC really soft in my opinion.

I then tested the lifters that were on the cam.

They tested 57/58 RC, not a problem i think.

I then tested a 13 Yr. old Bullit solid flat tappet cam, still good after a couple hundred passes on it.

It tested 34/35 RC a full 5 points harder than the newer Comp hydraulic cam.

I then tested a new never run set of solid flat tappets lifters

They tested 60/61 RC

I then tested a solid roller Comp Cams Cam

It tested 58 RC

I then tested a set of Comp Cams Extreme duty .180 offet solid rollers
lifters.

They tested 38/41 RC

I tested all the lifters on the body portion of the lifters

the Cam companys are saying the problem is with the lifters, I think that's BS, it's a cam core problem and they don't want to address the cam hardness problem, I doubt if they even have a Rockwell tester, ofcourse the like of Zinc in todays oils are a contributing factor also.
They are now putting oil holes in the solid flat tappet lifters for an extra fee, i think howards cams started this.

In conclusion they are using cheaper softer cam cores, and are not really intrested in solving the problems, but would rather sell hydraulic roller cams which cost as much as $700.00/$800.00.

JMO

Zip.
Which cam cores did you test?
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Old 07-29-2013, 08:45 PM
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bixblk
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Default cam/lifter hardness

Thanks Zip
Great info
Jeff M.
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Old 07-30-2013, 05:17 AM
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zipper06
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Which cam cores did you test?
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I don't know who supplied the cores to the cam grinders, i only know where the finished products came from.

6 to 7 yr old Comp cams hydraulic flat tappet cam

13 Yr. old Bullit solid flat tappet cam

solid roller Comp Cams Cam

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Old 07-30-2013, 06:32 AM
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roadkill2
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Good Information and suspicions confirmed . .

However . . .

Empirical evidence shows that the greater the differences in hardness of two "Conflicting" metals, the less likelihood of "Bi-Metallic Galling" occurring. The catch to all this is "Adequate lubrication", because the softer metal will gall almost instantly once the lubricant is removed for ANY period of time . . The Crankshaft/Bearing symbiosis is one such example.

This phenomenom is why the cam manufacturers can use softer metals in their camshafts when solid or flat tappet lifters are used. You'll notice that the hardfacing is very adequate on the Roller cams and the differences in hardness between the cam and the roller faces are closer together, although still not the same. Oddly, metals of the same hardness will gall quicker than those that aren't when put together . .

And . . Back when many of us used magnetos for our ignitions, the turning resistance on the cams when using engines with a Mag/Distributor driving off the rear of the cam was a lot greater than it is today with the "Smart Ignitions", where all you're spinning back there is a rotor. This caused the cams to actually twist, retarding both your ignition and the valve timing. Not to mention in many cases, total camshaft failure. This forced the cam manufacturers to use billet stock for their products and many of us became "Spoiled" because we got camshafts that rang like a bell when tapped with a wrench, were hardfaced and NEVER wore out . .

We don't need cams that tough anymore. And in most cases, if a cam and lifters are pre-lubed when the engine is put together with a good anti-seize, and you build oil pressure before you ever spin the whole engine, You'll never "Wipe" a cam lobe. But, it happens more than it used to because the cams certainly aren't made of the same stuff . . And our spring/valve seat pressures are so much greater.

The Comp Cam we're using in our 582 right now has about 250 passes on it and it's "Brand New" . . Of course it's a Roller so it should, but we did wound one when a lifter failed a couple of years ago. And it didn't take long! Just about half a pass! Looked like you took a Parting Tool to it! But it ate the roller too.

Bottom line, yes, some cams aren't as hard as others, even from the same manufacturer, but for the most part, they're pretty damned good when you look at the RPM, the seat pressures we ask for, the lift and duration of the cams and the frequency of use, as well as the cost.

We weren't doing what we do now only 20 years ago . .

Need to make a correction . . We have just a little over 150 passes on that cam . . . That's about 40 miles! Time flies when you're having fun!
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Old 07-30-2013, 08:21 PM
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zipper06
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There is some read on speed talk on cam cores, Mike Jones and others, google cam core and go to speed talk, lots of good imformation, things i never though of, but they make sense.
Back in the mid 60's i was running solid flat tappet cam on a blown A/mod sports car also competerd in B/GS, but we didn't have the spring pressure that we do today.
However every cam i checked i've ran. Hydraulic flat tappet cam was in my El Camino, with only 110 LB spring pressure (it went flat) The Bullit solid flat tappet cam i ran in my 406" motor with 135 LBs spring pressure and it's like new after more than 200 passes, the Comp cams solid roller, i ran 240 LBs pressure and it's also good.
The talk on speed talk is that the older cams were chilled iron, but the cam grinders hated them because the were harder to grind.
As RK says in the old days we ran Magnetos and they would wear out the distributo gear, (IE front drive distributors) i run one on my blown sm/blk, mainly to keep the timing closer from cam twist with a .900 base circle or less, my 434 has a .870 BS. it's a .723 lift with 1.6 rockers

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