Camshaft damaged. How bad?

[Nottajeep]

78 2F
I was replacing the oil pan gasket and saw this on the cam lobe
Truck is not running rough so I am wwondering if I should pursue any remedy?

Compression test over a 1 yr ago was 125 across all 6.
I may retest to check again.

 

[broth9640]

Any chance you can zoom in for a better pic? My hunch is to run it, but I also subscribe to the idea of "while your in there".

 

[Nottajeep]

Any chance you can zoom in for a better pic? My hunch is to run it, but I also subscribe to the idea of "while your in there".

See if this helps

 

[Fireman]

Run it.

 

[Mace]

If you are really anal about it you can put a dial indicator on the pushrods to see how much lift you are getting.

If not, button that bad boy back up and do as the pyromaniac suggests...

 

[Spike Strip]

What oil are you running?

 

[Nottajeep]

What oil are you running?

Mobil 1 15w-50

 

[Nottajeep]

If you are really anal about it you can put a dial indicator on the pushrods to see how much lift you are getting.

If not, button that bad boy back up and do as the pyromaniac suggests...

I tend to agree. Truck runs great going 65mph down the road.
Maybe a good ZDDP oil will keep it from degrading further?

 

[shawnfj40]

Just to chime in.......Run It!

 

[offr0adlim0]

I'd run it. But... if you want to replace it let me know I have a new Man-a-Fre Performance cam kit available.

 

[FJ40Jim]

It runs now. Lifter/lobe failure doesn't lead to catastrophic failure. The cam & lifters are already trash, no extra expense is incurred by waiting.

It will continue to erode, which causes a loss of airflow through the affected cylinder(s). This does not reduce the compression readings (and may increase reading), but does cause a decrease in power. When it gets dangerously slow, then it has to be addressed.

 

[Nottajeep]

It runs now. Lifter/lobe failure doesn't lead to catastrophic failure. The cam & lifters are already trash, no extra expense is incurred by waiting.

It will continue to erode, which causes a loss of airflow through the affected cylinder(s). This does not reduce the compression readings (and may increase reading), but does cause a decrease in power. When it gets dangerously slow, then it has to be addressed.

Thanks Jim!
Do you forsee this eroding to be very gradual as in 10 of thousands of miles or rather quickly (couple thousand miles)?

FYI- finally got my dissy and carb working excellent since your rebuild. With the valves adjusted, everything seems really good until this hiccup

 

[FJ40Jim]

Hard to say how fast the cams wipe now. With good oil it was only a couple random lobes that would get through the surface hardening, then they would erode relatively slowly after the peak of the lobe was blunted. With modern crap oil, they are all failing, but I don't have enough data yet to say if the speed of erosion is dramatically faster.

 

[brian]

from the pictures, it does not look like damage. rather a casting flaw where the lobe didn't have enough material to fully machine off.

 

[ColonelMustardFJ40]

Keep an account of how much your valve lash changes between adjustments. If they tend to be loose every time, there is wear.

 

[Nottajeep]

from the pictures, it does not look like damage. rather a casting flaw where the lobe didn't have enough material to fully machine off.

That's a good thought. I was trying to figure out how a lobe has chunks removed???

 

[Nottajeep]

Hard to say how fast the cams wipe now. With good oil it was only a couple random lobes that would get through the surface hardening, then they would erode relatively slowly after the peak of the lobe was blunted. With modern crap oil, they are all failing, but I don't have enough data yet to say if the speed of erosion is dramatically faster.

Oils today are pretty stout if you are wise enough to use the high ZDDP type. Sounds like this wear could go fairly slow if I maintain it correctly. Thanks again!

 

[FJ40Jim]

Its not a casting flaw. New cams don't pass QC if they look like that. That type of failure is called spalling. The surface hardening is stronger than the underlying cast iron, and the stress locked into the hardened outer layer makes it want to pop off the base casting. It's like the hard coating coming off the outside of a chocolate covered ice-cream bar. Hmm, I'm gonna go have lunch now...

 

[snaggletto]

Could someone with a dial indicator measure lift at the top end and determine how much wear the cam lobes have on them?

 

[FJ40Jim]

Yes, the FSM lists a new spec, as well as a discard spec, for lift @ the valve.