Flat tappet lifters, wear patterns, cam lobe taper and other things. Let's swap opinions and ideas.

[Kern Dog]

My feeling is basically that, if a new cam/lifter fails within 1000 miles, it started that process(of failing) during the break in.

Watching the Powell machine videos I saw enough evidence of poorly machined lifters to know that there are going to be cases where they are the culprit responsible for the failure.
I’ve measured the taper on cams that failed and know sometimes the taper is insufficient, and that the cam was surely a contributor to the failure.

The point being……… I don’t paint the picture of the current FT breakin process as being all “roses and unicorns”.
If you want to stack the deck in your favor, take all the precautions………and then hope for the best.

See, this does help.
The manufacturers want to blame the installer or the oil. The installer wants to blame the manufacturer. I have not heard any major oil company blame themselves. In fact, specialty oil companies have blamed the No zinc oils as a valid selling point to market their oils.
Dwayne’s (as well as others here) input leads me to think that due to some inconsistencies in manufacturing, the fault can be placed in several areas.
People drive with no seat belts and never have a collision that could kill them. Some people smoke and never get cancer while others might take every precaution and live healthy yet still die young.
I appreciate all the input and guidance on this matter. I hope that it benefits others as well.

My engine turned 550 HP and 675 Lb Ft of torque when I ran it on a chassis dyno at the Hot Rod Power Tour (as driven on the tour: full mufflers, air cleaner on, etc.). This was a "fun run" event, so I had no opportunity to tune anything. The horsepower dropped off after about 4900 RPM. Something was going on, and it likely is a fuel delivery problem. With 675 torque, Horsepower should be up over 600. But I haven't had time to diagnose the issue and find that lost HP.


EVERY TIME. Also, my father-in-law's shop won't even build a flat tappet engine without lifters that direct oil the cam (they do this through a small hole drilled in the bottom or a small groove in the lifter that allows oil to seep through on to the cam).

The No flat tappet builds practice seems to be popular for many engine builders. The hassle of replacing a dead cam and cleaning out all the debris really sucks.
I’ve seen in videos where the cam lobes have a different degree of taper compared to the lifters even when they are the same brand. It seems that you’d expect them to match for equal load bearing at the lobe/lifter interface. Maybe since the lifters are actually rebranded instead of made and machined in house is the main reason?
This has me curious about the process of refacing original, used lifters. It seems that if the new cam is measured for taper and then the lifters are refaced to match, you drastically reduce the risk of those leading to a failure? This still makes me wonder that at what point can you push it… if you have properly matched lifters and lobes, would there be a known point of spring pressure or valve lift where reliability drops off dramatically?
Looking at how a lifter rotates and slides on a cam lobe, I wonder how the heck they don’t fail sooner. Think about all other metal to metal interfaces there are in an engine. The crank spins in the block while supported by bearings made of a softer metal while relying on a wedge of oil. The piston rings slide along the bores millions of times. The timing gear has a chain that rubs the sprockets when turning. The rocker arms pivot on a shaft. Most of these only last because of pressurized oil but the lifters just get splash oil that squirts from the rod caps? The lifters are under greater risk of failure as the spring pressures go up, right?
For the guys that have never had a cam or lifter failure, did they just have tame combinations or were they just incredibly lucky?
My first three cams in Mopars were the 280/474 in my first 440, an MP 284/484 in my second 440 and the 292/509 in the stroked 440. None of those went bad despite conditions for break in were not optimal and this was when I knew even less than I do now.

 

[padam]

I’ll just put this out there.
A big part of manufacturing quality is having a system that makes it impossible to make bad parts.
Also in the 70s-80s the Japanese started following the teachings of Deming on quality, which the US manufacturers rejected.

That led to the Japanese dominance of our auto market.

From what I see in current manufacturing, companies have moved to outsourcing to the lowest bidder. They also eliminate employees with the most experience, preferring to bring in fresh faces that may be smart, but don’t stick around long enough to master the process.

This leads to decades of practical knowledge being lost a little at a time.
Many managers in factories don’t even know what they don’t know.

 

[coronet68mx]

Your valve springs are too tight change them.

 

[Geoff 2]

Thinking out loud....

With a re-ground cam, the lifter travels less distance each cam revolution. The actual speed of the lifter contact surface [ area of contact with lobe ] is also less because for the same cam rpm [ compared to a full size cam ], the lifter covers less distance. Maybe there would be a small improvement in lobe/lifter longevity from less total contact time between lobe & lifter?

 

[OneWheelPeel]

I was under the impression, and I’ll say this is something I could have read in a really out of date magazine, that you can’t just resurface lifters but the surface needs heat treatment too. Is that ever the case?

 

[Kern Dog]

I used to think that all camshafts were hardened. I was surprised to learn that they were not.
Many years ago, Comp Cams advertised of a process they offered known as Pro Plasma:

Here is a nugget that I don't recall reading before, underlined in blue.

 

[Ceedawg]

I used to think that all camshafts were hardened. I was surprised to learn that they were not.
Many years ago, Comp Cams advertised of a process they offered known as Pro Plasma:
View attachment 1751468

View attachment 1751470

Here is a nugget that I don't recall reading before, underlined in blue.

View attachment 1751473

After any of the Chryslers engine were built they were test run using propane for fuel. There was generic hookups for water (hot) and the intake (no carb) done on a test stand way before being installed in the car, definitely not at 2200 rpm for 20 minutes. Just a break in engine oil (non detergent iirr) was used and run maybe a minute. SO WHY do aftermarket cams need SPECIAL procedures? Also Whatever spring came on that engine is MORE than adequate unless you’re planing to turn it 7-8000 rpm, which to me (too much spring pressure) is the main cause of cam failures. On my Max Wedge engine (1974) I could literally turn the spring with my fingers (Isky roller with the rev kit) turning it 6800, thinking it was an accident waiting I changed to a stronger spring but no difference seen.

 

[Ceedawg]

Thinking out loud....

With a re-ground cam, the lifter travels less distance each cam revolution. The actual speed of the lifter contact surface [ area of contact with lobe ] is also less because for the same cam rpm [ compared to a full size cam ], the lifter covers less distance. Maybe there would be a small improvement in lobe/lifter longevity from less total contact time between lobe & lifter?

The base circle is the only thing affected by that, ramps and lift would be the same distance or more if bigger cam specks. The lifter on the base would see very little pressure from a hydraulic and none from a solid (lash).
On my 509 hyd in the 383 I ran zero lash with adjustable rockers, I would turn the pushrod then tightened the nut when it didn’t turn, no pre load.

 

[Geoff 2]

No, the base circle is not the only thing affected. A reground cam has metal removed from the whole lobe, not just the base circle. Wrap a strip of paper around a cam lobe & mark where the ends meet. Lay out the paper & measure the distance between marks; say it measures 4". That is the distance the lifter is in contact with the lobe for one cam revolution. Now re-grind the cam, measure again with the paper; now it is 3.7"........

 

[Ceedawg]

No, the base circle is not the only thing affected. A reground cam has metal removed from the whole lobe, not just the base circle. Wrap a strip of paper around a cam lobe & mark where the ends meet. Lay out the paper & measure the distance between marks; say it measures 4". That is the distance the lifter is in contact with the lobe for one cam revolution. Now re-grind the cam, measure again with the paper; now it is 3.7"........

Think about it, IF a cam is ground with the same or MORE lift and duration the lifter will have the same distance to travel. The only loss will be on the base because that’s where the cam is reground. They can’t add metal to make more lift or duration. Never heard of a regrind to make a smaller cam except on a big roller cam. When grinding a new blank compared to a regrind, to make same profile, the only difference is the lifter sits lower in the lifter bore. They can’t regrind a cam that has .400 lift into one that has .550 lift, to much has to come off base circle, theres a point of no return

 

[cudatom]

I do think a lot of the new grinds with the agressive ramps probably crap faster and more often. If you grind a cam with an agressive lobe ramp, make it a roller.

I would have to agree. I used a Hughes cam in 2002, no problems with break in and ran it for a couple seasons. Still not many runs due to family events and wk. Maybe 150 total. The cam didn't wear out but Hughes springs were toast. Never hd springs wear so fast.

To the original post, we have done 4 engines since 2000. All four are still running except for the one with bad springs. We always checked lifter bore size, ran edm lifters(amc) and nitrate coated cams. Coincidence maybe but we haven't had any failures.

 

[Geoff 2]

Ceedawg,
Post #90. I did think about it.... & before I posted. I was talking about re-ground FT cams, but roller would be the same.

Get an old cam & cut the core either side of the lobe so that you are just left with the lobe. Hold it up to eye level. If you remove 0.020" of metal depth off the lobe [ as you would be removing metal in a re-grind ] , the lobe surface length that is left has to be less than what the original had. It cannot be the same or bigger....The surface length is what the lifter base travels over...

 

[Ceedawg]

Ceedawg,
Post #90. I did think about it.... & before I posted. I was talking about re-ground FT cams, but roller would be the same.

Get an old cam & cut the core either side of the lobe so that you are just left with the lobe. Hold it up to eye level. If you remove 0.020" of metal depth off the lobe [ as you would be removing metal in a re-grind ] , the lobe surface length that is left has to be less than what the original had. It cannot be the same or bigger....The surface length is what the lifter base travels over...

Again you can’t make a longer duration and more lift by decreasing the distance from starting to open the valve and closing the valve. The distance loss is in the base circle area. If metal is removed from base but the cam profile stays the same you gain lift and a little duration but lose distance around the lobe. They can’t grind an existing cam without losing the base, they might just touch the point to clean it up a little but 99% comes off the base.

 

[Ceedawg]

Again you can’t make a longer duration and more lift by decreasing the distance from starting to open the valve and closing the valve. The distance loss is in the base circle area. If metal is removed from base but the cam profile stays the same you gain lift and a little duration but lose distance around the lobe. They can’t grind an existing cam without losing the base, they might just touch the point to clean it up a little but 99% comes off the base.

Also the reason one can’t measure lift with a micrometer it has to be set up to use a dial indicator going from base to point. So much more but we’ll discuss that at a later time

 

[Kern Dog]

As I stated before, I use to think that all cams and lifters were hardened to protect against wear. My reasoning for that was from seeing engines run for years with no problems and then in a short time, the cam or lifters just wore away. My thought was that the protective treatment just wore away and the metal underneath suddenly started grinding away. This theory is supported by how we all were told to install hardened exhaust valve seats when the lead in gasoline was phased out.
Since I've learned that there is no protective covering on these parts, I am boggled at how they last as long as they do with no wear.
Assuming that the break-in goes well and that the proper valve springs are in place, what ensures long term durability?
I'd think that sticking with the proper oil is tops on the list along with avoiding extended idling. Don't let the engine run low on oil or go too long between oil changes. Other than that, what else helps?

 

[ckessel]

Saw this at the Comp booth today. Maybe these plus having the bump stick Nitrided will be the cure.

 

[ckessel]

While cruising through the SEMA show today, I spied some bump sticks at the Scat/Procar/AFR booth. The company is Andrews Products out of Il. They have recently been purchased by the equity company that own Scat etc. I talked to the guy there, no auto catalog as they primarily sell sticks for Harley's. On display though were roller units for V8's. He said they are just recently advertising the V8 stuff but only roller. They have been the supplier, stealthily behind the scenes, for many of the known cam companies for many years. They are the supplier and engineering company for the others we are familiar with. According to him, the majority of the cast stuff plus lifters are overseas made and are not consistent with the metallurgy consistency. AKA soft. Interesting! He reiterated that this is so due to the lack of need/sales for cast cams compared to roller units.
Another thing being talked about in some of the above posts is regrinding the cam. This can work up a point. Since you are removing material, especially on the backside, the lifter can potentially drop far enough in the bore to uncover the oil journal creating disaster.

 

[Geoff 2]

Your run of the mill FT lifters are not hardened, as in a separate hardening process. They are cast iron & are the same hardness throughout. This is reason you can re-face them more than once [ I have done it 2-3 times ].

 

[Geoff 2]

Ceedawg,
Have a look at the pic. The lifter travels less distance travelling around the surface of the lobe with a re-ground lobe [ red ] than it does with the original lobe [ black ].

 

[Ceedawg]

Ceedawg,
Have a look at the pic. The lifter travels less distance travelling around the surface of the lobe with a re-ground lobe [ red ] than it does with the original lobe [ black ].

View attachment 1753089

The point is NOT reground, what I been trying to ‘point’ out, only the bottom is. Just leaving the point the same makes cam have more lift and duration.