chevy406

My failed cam lobe didn't exactly sound like yours mchicia1. Mine wasn't as distinctly valve train sounding as yours. Yours sounds like it's coming from the rocker arm where mine was less distinct. Very difficult to describe variations of "ticks". In your case, try to isolate which side the tick is coming from, pull the valve cover and check for broken spring or loosened rocker arm bolt. If it all looks ok, then you may need to pull the heads and replace your lifters.

mchicia1

Thanks for the thread update Chevy!

I am already going to a bigger cam, so I may as well just pull the heads and poke around in there. I have the MLS gasket on there so it is not a big deal pulling and putting back on the heads. Better safe than sorry. This is of course assuming I don't find anything under the valve covers.

slow ride

My car had a cam starting to do this when i tore it down 4-5 years ago for a broken ringland (much like the op's even). It was in way better shape than these pistures so I sent it to comp and had it reground into a 228 232 xer cam as it was a 232 236 xe grind. It's been working well in a friends car for years.

I don't think it had enough spring pressure or something as I just took out the new stuff after 14k or so and it looks great. Engine had the limiter set low so it was easy to bump it from time to time on the old stuff where it's now at 7k and I never hit it. Same springs as before, but I did shim them for proper seat pressure. Cam is actually a larger 238 242 xer grind.

Rick@RKT Performance

This Comp cam came out of 2010 LS3 Camaro. There was a squeeking noise coming from #5 cylinder. Caught it in time so there were no other damage.

Z06ufgrad2002

You got the hood off by yourself? Geez, I was thinking of getting 2 people to help me so it doesn't get scratched. I just had it repainted 2 months ago.

sabastian458

I have 2 cams and a set of rollers like this, LG cam and Vengeance cam. Both less than 20k on them. They are currently being mad into camshaft lamps for my enjoyment

2nd time I looked at the cam bearings and saw copper also, new build commenced, never looked at the 1st engine bearings.

0Josh@SpartanLSX

Camshaft failures are actually very common amongst Comp Camshafts nowadays. I've got an entire scrap bin full of them that have fallen apart inside engines. Some of them within a matter of 5-8K. We no longer use Comp for this reason.

Someone else mentioned ZDDP in this thread. These engines absolutely do need more Zinc than today's oils offer so everyone reading, do yourselves a favor and grab some Lucas zinc additive and add it to every oil change.

Bill Curlee

Good info!

zeevette

I'm going with ARP head studs, if I have to do this again.

Bill Curlee

You will TOTALY APPRECIATE the head studs once you install them! They are SOOOOO MUCH better than the bolts!

I also installed the ARP Damper Bolt! Another better approach!

Just make absolutely positive that there is NOT ANY leftover coolant and or dirt in the cylinder head bolt holes in the block.

Purchase a tap specifically designed to CLEAN the holes so the studs go all the way to the bottom of the hole!

vettenuts

I switched to Amsoil Z-Rod for this very reason. Made for flat tappet motors and the 30W is high in the range of 30W requirements.

GoatKart

Old as hell post, but as a Materials Science Engineer, specializing in Metallurgy and Ceramics and since it was drug to the top again...


I would guess the lifter failed and took the cam out with it...

Given the wear of the cam, it wasn't and issue with a bouncing lifter, the lobe was taken out evenly on both sides... When you have bouncing valve train components, its almost always off the nose of the lobe, leaving one side "clean" looking and one side where the landing is, looking rough from the impact of the lifter... It can actually cause a lobe on a cam to have a small concave spot that wears out over time..

Since the nose was taken out, best guess is the lifter was sliding over the nose when the spring pressure went up.


The lifter is showing classic signs of surface fatigue pitting. Origins of that type of failure can be from anything from improper heat treatments, case depth failures, poor lubrication, excessive stress at the interface of the two materials.


Chances are it started when the lifter started to age... The excessive spring pressure made it so the lifter roller didn't roll quite as well as it used to. As soon as it started to slide a little, this is a perfect storm for this type of fatigue. Pitting made the surface of the roller basically sand paper on the cam lobe.

You'll also note, the pitting continues through the surface area where the wear from what I assume was the lifter continues.

However, this is based off two pictures, viewed on the internet, and no hands on work with the specimens.... so just .02 from an educated source.... Just a best guess based on 5 minutes of examining pictures...

PRE-Z06

Curious if the OP ever tested the corresponding valve spring pressure to see if it was indeed weak as the XFI lobes are pretty soft being they were intended to work with single 918 springs. I have seen this happen with stock cams as well and believe the issue is the oil quality. Comp is the biggest supplier of aftermarket LS camshafts so it is naturally going to have the most number of failures, not necessarily any higher percentage. Though that is debatable with most guys who surely didn't add power to putt around

C66 Racing

AMSOIL Z-ROD 10w30 Synthetic Motor Oil (Product Code ZRTQT)
(zinc – 1440 ppm, phosphorus 1320 ppm)

More than happy to get AMSOIL products for forum members at dealer wholesale pricing, about 25% below retail, via the AMSOIL Preferred Customer Program. Drop me a PM if interested.

Z06ufgrad2002

Thanks for the info. I will start doing this after a new cam goes back in.

1999corvettels1

Does one need this additive for a stock LS1 also?

vettenuts

I think for stock I would run the Mobil-1 High Mileage that keeps many of the additives it had from several years ago rather then the newer version which meets SN requirements and in doing so removes these additives.

1999corvettels1

I learned something new, I had guessed the high mileage oil was formulated to help old valve seals and gooey gaskets lol.

So, one would want to run this on a newer or brand new Corvette, as well?

ZeeOSix

Is that really true? Why are these oil formulations always changing and removing more and more additives that keep engines from wearing out. I mean the main purpose of oil is to prevent wear.

Z06ufgrad2002

Any good two piece front covers available? I hate the idea of removing the HD just to pull the cam.