Hello Cam-ers,

I am rebuilding my 2002 5.3 LM7. Should I replace the cam or run with it?

This is my 1st roller lifter engine overhaul so I do not know how much if any wear I can get away with. So that is why I need some help. There is one lobe with wear.

I am putting in new Hy lift HA2148SE lifters now.


The cam has about 57000 miles and 13 years on it. Ran Z06 valve springs and Comp Cam adjustable roller 1.175 roller rockers. The cam is a Comp Cam that my turner ordered for my heavy 5700 lb. 4X4. It has been a good cam with good torque. The spec’s are:
LS1 3709R / 3711R HR114.0
Valve lift / rockers intake .574” exhaust .5775”
.006” lift _______265__________ 269
Valve timing open close
@.05”_______ INT 6- BTDC ____38 ABDC
___________ EXH 44 BBDC____ 8- ATDC
@112.0 int Intake center Line
Duration @ .050” ___Intake 212 ____Exhaust 216

Lobe lift Intake .328” Exhaust .330”

Lobe separation 114


I wrote all that because I really do not think I have to upgrade my cam, the major changes have been the convertor and ported heads [in signature] since the cam install. But I am upping my CR with flat top pistons.

So now for the wear, one lobe has pitting in the center on the lobe about .090” wide with matching pitting on the old roller lifter. I do not catch anything with the finger nail drag test but it is pitted. I did lightly polish [2000 grit paper] the area to see if it was something stuck on the surface.

Pic below, let me know what you think. The last one is a “good” lobe.

Thanks

going up

coming down

Old 2002 lifters, will be replaced

Good lobe

 

Time for a new cam in my opinion.
Not worth taking a chance with that lobe.

 

IIRC, Comp had issues with cores and hardening back when.
Thats likely to just keep getting worse.

Ron

 

Yup, the pitting would have to be from the cam or the rollers. I did not know that Comp had issues with the core.
Great now I have to pick out a new cam. My brain is hurting already!
Maybe after 13 years Comp will warranty it!

 

I don't know who Comp used for heat treating but there was a heating treating company in the US who had serious quality control issues several years ago.

 

Thanks to all--
Looks like I can make a heavy duty lamp stand out of the old cam shaft! There is a hole already drilled through for the power cord, or maybe I should make it Solar Powered and go Green? Naaa burning Coal and Oil is good for the trees, they need Carbon Dioxide. We burn coal for electricity in ND, [do not quote me on this, but it is close to the truth] we have the lowest electric rates and the cleanest air.

Seriously, I should start another thread about: Should I change the cam specs when I order a new one ?
But----Going to do my home work first on "The Art of the Cam Shaft" so I can APPEAR really smart on cam design discussions! That might take awhile!
So thanks Comp!