AU N EGL

for any road racing / track days keep the lift UNDER .600 for reliability in an LS7. .650 is still too much for that much high rpm use.

something in this line

258 / 258 @ .050, .578 / .578 lift, 110 LSA

3000 to redline several times a min for 20 to 30 min at a time, beats the living crap out of a valve train.

RagingGrandpa

My stock LS7 failed two lifters, I noticed new ticking noises and tore into it. This was a mfg Jun/06 car, 80,000 street miles, ~1,000 track miles.

.02

Shown below: #3 exhaust (roller bearing felt irregular), #7 exhaust (fretting), #5 exhaust (normal)


Cam surface looks similar; I did measure full lift though.

DSOMC6

Did you re-use that cam? Even though the lobes measure full lift, I'm guessing there's a groove ground into the center of the cam lobe which will cause the new lifter roller to ride on it's outer edges.

RagingGrandpa

Cam is toast, just pointing out that even though the surface was bad, you'd never know it just from measuring lift at a rocker, etc.

DSOM- how "old" was your 2006 when your lifters failed? Track usage?

DSOMC6

Yeh my cam lobe was trashed as well.

It was only one lifter that actually failed.
The car had about 58,xxx miles at failure.
Twin turbos and cam added at aprox 20,000 miles.
Never tracked, mostly frwy miles.

New lifters, lifter trays, heads machined with new manly dual valve springs, new valve seals, new higher lift cam, APR head bolts, New Katech C5R timing chain, New Powerbond UD pulley pinned to crank.

It runs pretty strong now.

bowtiguy

My engine builder syas it amazing the power his drag car picks up with new "fresh" springs ( his last 8-12 pass's), but he is running a 1.000" + lift SB2 drag motor.

It was amazing the power my car picked up getting the lift in my cam back.

I'm running an under .640" lift cam now, more duration and I still hit the same top speed down the back straight of my favorite road coarse.

My power band is wider too.

08VRZ06

I don't know what oil you have been using but you may want to switch to an oil that has a higher zinc/phosphorus content such as Royal Purple's HPS or XPR oils or Redline's Race Oils.... I had the same type thing happen to my stock LS7 that I've never tracked or run past 6000 RPM. Vette had 23 - 24 thousand miles when found......







Mark

DSOMC6

I've debated this.
Anywhere to purchase any of those oils at a discount?

I have an F/I set-up and change my oil and plugs about every 3-4k miles.

RagingGrandpa

Hey thanks for posting, that's reassuring to me to see you had so much wear but the roller remained intact.

0Louis @ LG Motorsports

Mike, the pic you posted is due to hardness. Ive seen it happen in the past, maybe 3x in the last 10/12 years on LS engines. Each time, the cam was sent for harndness, and of those 3, 2 were not up to spec and one was too gone to determine the root cause.

The added zinc in the oil will help, lots of flat tappen/solid roller diesel guys must use oil with a lot of zinc when they do cam swaps in order to get them to seat properly.

Lets clear up one thing, lift doesnt mean much interms of cam/engine reliability, considering we are no more than 10% lift than stock.

What matters here, is the lobe profiles. Im not sure how the LPE profiles are, but for consistently high RPM engines, the duration at .200 tappet lift tell more about a cams radical, or not so radical behavior. This is where quite a bit of the work is done, leading up to the nose of the cam where it pushes the lifter up, and compresses the spring, opening the valve against cylinder pressures.

I would certainly attribute this to an isolated hardness issue, and some oil analysis, magnetic drain plugs, or a scavenge filter in your return line to the tank would have told you something was up, if your hearing wasnt up to par

Hope all is well!

Louis