Cam And Lifter Hardness Testing

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If you don't mind sharing, who was the cam manufacturer?
We discovered what the root cause of the problem was.
The block had incorrectly installed lifter bushings, which resulted in a couple of lifters having no rotation.

But, to answer your question, that was a UD cam from before they closed.

Several years later on one of the mild circle track SBC builds, one cam lobe went flat on break in.
Pulled the cam, 15 were perfect, one was junk.
Slid in another cam, checked for rotation...... all were fine except that one hole. Zero rotation.
Ordered a cam with an extra .001 taper.
Even with that (.003 taper) there was barely any rotation.

That’s back when Schubek was still around.
Put one Schubek in that hole....... no problems.
Those don’t need any rotation.
 
I agree with this entirely.
I wonder if the non-working parts of a camshaft have the same hardness? It would depend on the process used and perhaps that would be different from manufacture to manufacture. If the entire camshaft is case hardened and THEN it is ground, I would think testing in a non-ground area would indent slightly less than a ground working area, thus giving a higher rockwell. I'd like to just say "buy American" but I'm not sure that is valid anymore...
If cam material is cast iron, its hard already. If it is cast steel, I believe it is milled to shape oversized and bearing surfaces and lobes are induction hardened, then straightened and ground.
 
I've always wondered how much damage, if any, is done when the engine is just cranking. In the old days I think the break in paste got wiped off but the new stuff is supped to cling better.
Like the guy's on the performance TV shows. lol They seem to not waste cams when they run into problems during the initial start.
I've seen them crank and crank on those shows. lol
They have been lucky or they just don’t tell when they wipe a cam. That gorilla snot lube is more than likely wiped off during the first few initial spins. That’s why it’s important to prelube with an electric drill and get it fired off and up to break in rpm immediately.
 
Like the guy's on the performance TV shows. lol They seem to not waste cams when they run into problems during the initial start.
I've seen them crank and crank on those shows. lol
Those shows are for entertainment only. I like them just to see stuff assembled and run, but I don’t trust them.

Ever see the stroker 360 with Trick Flow heads run on the dyno after it was built on that Powernation show? It’s been two years and no dyno runs shown. But they suspiciously assembled a different similar combo and ran it on the dyno.
I suspect there was problems in the original and the sponsored parts were not allowed to be shown having issues.
 
[1] FT cams are cast iron based, same hardness right through & can be ground to any size.
[2] Roller cams such as the 8620 core, commonly used, is steel & is hardened only to a certain depth, & that limits lobe lift, LSA, etc.
[3] Experienced engine builders have experienced FT break in failures so there ARE cam & /or lifter failures.
[4] There ARE soft lifters. I had a cam fail with lifters that came in a Crower box [ Crower do not make lifters ].
 
I think he said there should be .002 taper on a good cam. You should be able to pick that up with a set of mics.
Right quick like. On the subject of taper, I've often wondered just "how much" of an advantage the low taper camshaft had in the original 440 Six Pack and Six Barrel cars. It was supposedly done to reduce friction and "free up" a little power. I just wonder if it really worked and "how much"? I can't see it making a noticeable difference.
 
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1969 service bulletin.

......and I had always thought that the six barrel special cam/lifter taper was for a heavier valve spring and longevity?
 
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[1] Roller cam is flat, although the rollers are often crowned. I believe the crowning is done to [a] help tracking [ b] the roller 'flattens' out under load for more even load distribution.
[2] The 440 6 pack low taper cam/lifters was to reduce wear with the stronger valve springs.
[3] Low taper provides more contact area, so less wear.
 
View attachment 1716020918

1969 service bulletin.

......and I had always thought that the six barrel special cam/lifter taper was for a heavier valve spring and longevity?
There'd be no reason to low taper the camshaft for heavier valve springs, since the specs were exactly the same as the standard road runner cam.
 
We discovered what the root cause of the problem was.
The block had incorrectly installed lifter bushings, which resulted in a couple of lifters having no rotation.

But, to answer your question, that was a UD cam from before they closed.

Several years later on one of the mild circle track SBC builds, one cam lobe went flat on break in.
Pulled the cam, 15 were perfect, one was junk.
Slid in another cam, checked for rotation...... all were fine except that one hole. Zero rotation.
Ordered a cam with an extra .001 taper.
Even with that (.003 taper) there was barely any rotation.

That’s back when Schubek was still around.
Put one Schubek in that hole....... no problems.
Those don’t need any rotation.
Has anyone indicated the ball will be picked up again on those, or is that product a dead duck?
 
Has anyone indicated the ball will be picked up again on those, or is that product a dead duck?

I think that deal is dead. It’s sad because I know they worked for a while any way. And I know they didn’t take valve float very well.
 
I think that deal is dead. It’s sad because I know they worked for a while any way. And I know they didn’t take valve float very well.


Reading up on them made me sell the set that I got in the group buy with my R3 block. Sold them and bought EDM lifters and ran them for five years on a .650 lift cam in my 422.
 
For the vast majority of avg./mildly aggressive sticks, they would eliminate failures. Combine that with something like Comp's case-hardening option, & this conversation'd be a thing of the past. Wonder if any of the cam companies looked into purchasing the patents etc.
 
Reading up on them made me sell the set that I got in the group buy with my R3 block. Sold them and bought EDM lifters and ran them for five years on a .650 lift cam in my 422.
Typical paradox, the cams that need the wear resistance they offer the most, put them in an enviroment they tolerate the least...
 
Human nature. Maybe they can’t accept and admit that they f’d up and are at fault. Blame hardness, machining etc. anything but themselves.
I know a major issues with wiped cams is guys Dont know how to start a fresh engine. I see guys with dead batteries, distributors 180 out, old fuel or low fuel, trying to prime and engine by turning it over instead of the right way, etc, etc.
I wiped out my first big camshaft, for some of the above reasons. 100% my own fault. At least I admit it. (A purple shaft mini express. Too much spring, vacuum leak, old fuel. I wish I could get another mini express and try again.....)
 
My friend and I built a number of flat tappet engines 20 years ago and I'm sure most didn't start right away. I doubt we ran them at 2000 rpm for 20 minutes either. We would have used ordinary cheap oil for break in purposes. There were no failures. Today's seemingly high failure rates are probably due to a combination of issues...some questionable parts here and there, engines have been rebuilt numerous times, low anti wear additives in oils, etc. This all reduces the margin of error.
 
I have never had issues with flat tappet cams on any builds I have done over many years. I guess there is always a first time.
 
Lifter may get locked in position and then a quick death.

RPM helps get the lifters spinning. On the starter, that RPM level isn't high enough and if a groove starts, you're dead.
I think this is why the engine needs primed and hopefully the distributor is set where it fires right off...:)
 
I have never had issues with flat tappet cams on any builds I have done over many years. I guess there is always a first time.
:thumbsup: me neither, there won't be a first either. I go by the old break-in, 1500rpm steady for 10 minutes.
 
I have done many cam break in's, for myself, my family and other people, I have had only 1 go bad, and it was an old MP cam, slightly used, and don't know what decade it was from, I think most people don't understand the process, the engine needs to be primed, the distributor must be right, fuel in the carb, not cranking until the bowls fill, and must fire immediately, no cranking for 10mins.
 
There'd be no reason to low taper the camshaft for heavier valve springs, since the specs were exactly the same as the standard road runner cam.


The heavier springs were for more rpm on the 1970 version............or so the legend goes.
 
If a good set of calipers are accurate enough to measure lobe taper (probably not) I measured .003 taper on a mid 1970's Crane solid flat tappet.
 
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