What caused this camshaft wear pattern

[HawkRod]

Your lifters may not have been rotating. The cam will partially rotate a lifter with every stroke. This must happen or you will get cam wear. Check lifters in the bores and see if there were any burrs or issues there. Without a cam in the block, they should just glide right through the bore and out the other side. The lifter bores in an engine are CRITICAL to making sure a flat tappet cam lives.

 

[70rrclone]

Thanks, I'll check that while its apart.

 

[padam]

I guarantee mine were rotating and I got the same wear. My guess is the modern materials are not up to the task of high spring pressures.

 

[Rebelrouser]

It was broke in with driven breakin oil and mostly valvoline vr1 10-30 oil. I think I did one oil change with amsoil 10/30 high zinc oil. Filters were wix . Ive never seen a failure like this. Im going to a solid roller and I want to make sure my bases are covered.

Cam or lifters are not machined properly; there is no rotation of the lifter. I have seen this on dozens of engines last couple of years. You can use any oil you want but on a flat tappet cam if the lifter does not spin on the cam lobe as it rotates it will simply not last. And I made the same decision you did several years ago, just run a roller and be done with it.

 

[OKDart]

Thanks, I'll check that while its apart.

Here's the procedure from Hughes, starts on page 2.

https://www.hughesengines.com/Upload/productInstructions/camshaft_instructions_Mar_2016.pdf

 

[4mulas]

Ill contact comp and see what they say. It already out. Its going to be disassembled inspected cleaned and reassembled. It going back together with a bullet solid roller

View attachment 1969681

Please post pictures of the bottom of those 2 lifters on the lobes in question when you have it apart.
I don’t think the wear pattern across the top is really the concern here, just the chips correct? Which would be core manufacturing issues, debris or something. Regardless, yes it needs changed for sure.

 

[padam]

FYI, reference info
Thread 'Looks like my cam and lifters are wearing out'
Looks like my cam and lifters are wearing out

 

[Cranky]

Yup....don't forget to use the correct intermediate shaft with a roller....solid or hydraulic.

 

[70rrclone]

Yup....don't forget to use the correct intermediate shaft with a roller....solid or hydraulic.

Im probably gonna go with a composite gear for the intermediate shaft.

 

[70rrclone]

@4mulas

10 out of 16 lobes look like these 2. All lifter bores passed the Hughes thunk test. Ive ordered the burnished ball for them anyway.
I did a quick measure with a caliper and all the lobes are between. .005 - .007 short of spec.

 

[PRHeads]

What are the spring pressures?
Rocker ratio?

Fundamentally, I feel like the load was concentrated on that failed area, the core got excessively work hardened, until pieces started breaking off/flaking away.
Could it be as simple as the core just wasn’t up to the task? Of course that’s a possibility.

One of the pitfalls of fast rate FT cams with high lifts are they have a smaller nose radius.
Smaller nose radius = less area to spread the load over

Was it nitrided?

 

[4mulas]

@4mulas

10 out of 16 lobes look like these 2. All lifter bores passed the Hughes thunk test. Ive ordered the burnished ball for them anyway.
I did a quick measure with a caliper and all the lobes are between. .005 - .007 short of spec.

View attachment 1971007

View attachment 1971008

Usually it’s lifter failure and not cam failure. Well the bad lifter usually makes the cam fail, lol. I haven’t seen that light chunking pitting going on with your cam before. The lifters look ok. And the wear pattern in cam not bad to me anyway. But I’m sure others know more than me.

 

[70rrclone]

It was a comp xe285hl with comps lifters and springs. I was chasing a valvetrain noise and went to a slightly heavier spring. I went from a comp comp 924-16 112 seat 355 open. To a TF16893-16 120 seat and 394 open. An increase of about 50lbs spring rate. In the end the actual noise was the cam gear coming loose because I failed to locktite the bolt. Ugh! No it wasn't nitrided.

 

[padam]

The lifter in the top pic is going flat. I had some that looked like that and the crown measured less than new.

 

[PRHeads]

I was chasing a valvetrain noise and went to a slightly heavier spring. I went from a comp comp 924-16 112 seat 355 open. To a TF16893-16 120 seat and 394 open. An increase of about 50lbs spring rate.

I’m not sure you’re grasping the whole “spring rate” vs “spring pressure” thing.

The rate is the change in force over distance.

A 400lb/in spring changes 400lbs in 1” of distance(and 200lbs in .5” lift).
Multiply the rate times the net lift at the valve, then add the seat force, for the open force.
Going by the Comp catalog, the 924 spring has a rate of 347lb/in.
The seat force at 1.850” is listed as 129lbs.
The XE/HL 285 cam is essentially .580” lift with a 1.6 rocker.
347 x .580 = 201.2lbs.
129 + 201.2 = 330.2lbs @ peak lift.

Changing to the TF spring(391lbs/in):
It’s listed as 130@1.850
391 x .580 = 226.7
130 + 226.7 = 356.7

Neither of those scenarios look like they would be problematic.
Although the TF heads generally have spring IH’s taller than 1.850……… so, for example, if the 924’s were installed at like 1.950, both open and closed loads would be “abnormally low” for a fast rate cam like that(especially with 1.6 rockers), and there could have been some lofting going on at higher rpm.

If you have decent notes from when the heads were set up, it might shed some light on the situation .

 

[70rrclone]

Thanks for the explanation. I knew that the spring rate was different than the spring pressure. But I didn't think about the math to figure it all out. Do you think the heavier springs and 1.6 rockers were too much for the lobe?

 

[PRHeads]

Do you know what the installed height was with them?

 

[autoxcuda]

Cam or lifters are not machined properly; there is no rotation of the lifter. I have seen this on dozens of engines last couple of years. You can use any oil you want but on a flat tappet cam if the lifter does not spin on the cam lobe as it rotates it will simply not last. And I made the same decision you did several years ago, just run a roller and be done with it.

The two comp XE268’s my buddy ran were checked for rotation. Each lifter marked with sharpie on block and lifter, engine rotated, all lifters rotated. Both cams failed.
Much smaller cam, but XE series.

 

[70rrclone]

I dont have great notes for the exact height of each valve. The comps were installed as close to 1.90 as I could get them. + or - .010. The TF springs were 1.87 with the same + or - .010.
Is that too much variance?

 

[PRHeads]

+/- .010” is great.

The TF springs are PAC-1903……391lb/in, listed as 110@1.900 and 130@1.850.
391x .020 = 7.8
130 - 7.8 = 122.2
391 x .580” = 226.7
226.7 + 122.2 = 348.9

Personally, I don’t feel like that’s really enough spring to maintain control at higher rpm(with that cam & 1.6RR, with the fairly heavy TF intake valves).
But at the same time, the fast rate profile can really tax the Hyd part of the lifter at high rpm.
I kinda feel that situation is the worst of both worlds.

To take the Hyd part of the lifter out of the equation, I’d want more seat and open force.
Something like 140-150 seat/360-375 open……. But Hyd lifters don’t always play well like that.

It’s a bit of a catch 22.
The valvetrain needs what it needs for force to maintain control in the upper rpm…….. but that’s often more than the Hyd portion of the lifters cam effectively deal with.

All that said, It’s not all that likely that more spring force would have made that cam live.
So you’d still be where you are now.