I posted this symptom in my "Cam break in was a disaster" thread:

It idles fine and sounds good. I adjusted the valves both ways discussed - finishing with the EO/IC method. At higher-than-idle rpms, I can hear clacking from the valvetrain.

I've already done compression testing and there isn't any valve damage.

Is this normal for this cam? I'm tempted to lift off the valve covers and give each rocker arm another 1/4 turn. I thought I'd pose this question before I did anything. Thanks

are you using roller rockers? if so, they tend to make some noise.

I'm using the same Comp Cams Magnum roller-tip rockers I was using before. I'm basically asking is the lobe design of this "extreme" line of cams prone to more noise?

Also, IF I didn't break-in the cam properly, what would the symptom be if one or more of the lobes rounded out? Would it show itself this quickly?

XE cams tend to sound like a solid lifter cam with about .005 clearence. As long as it isn't clacking loudly I wouldn't worry about it.

The xe268 in my truck has been clacking away (mildly) for about 5 years now. If you haven't lost a lobe, then a little noise out of these cams is normal.

If you lost a lobe, it will show itself pretty quickly. The clicking will get louder and louder and you will be able to wiggle the rocker arm and tell very quickly which lobes are gone.

Keep driving it and see if the noise gets worse. If so, it's probably bad news....

I use the XE series profusely with both the 268 and 274s. I find only slightly more noticeable valve train noise with the 274 and can't discern the differences with the 268 from under the hood. I do run full roller rockers with my set ups.

But, since I run these all the time maybe I have gotten used to a slightly more noisy valve train and can't compare to a regular one? :rolleyes:

Hello amigos,greetings from Panama. I posted last week "Holley spiting fire". All of you point to a carb tune and timming. I did it,and you were right,guys. my engine is "another one" after the correct advised you gave me. This is my first HiPO project and I'being a little affraid of damage something. Because of my budget I could not buy converter & low gears yet.(have to be ship to Panama and weight a lot) and I don't really know what to expect from my Lunati 230°@0.050", 0.480" & 108 LCA into my Z28 1984 heavy Camaro. I realized that after I rev hi and let idle,the engine begin clacking any rocker arm for few seconds and then noise stop. My oil presure 70@ 2000rpm. What is the cause. I would not be able to test it on the road for a while,because I lost windshield and hood during a pass on down town streets by the time my carb was breathing fire. I left the hood unlock, oops. What a luck!
I'll appreciate any advise. Thanks.