Why is it that you get that tapping noice when you do a Cam exchange? My Cam guy said they all do it no big deal. Mine only tapps in 1st gear. Then sounds totally fine the rest of the time. Just gives my wife a reason to bitch when she gets in the car:>)

 

I think its the way GM set up the lifter design...with the cups and ****, as well as the angle.

The 565 in the race car has almost .800 lift, insane duration @ .050 and doesnt tap, lol.

 

Mine does the same thing, it taps at low rpms as you start out then gets quiet as it revs above 2k. I bought the car used so i have no idea what was done to it. I'm sure the oil pump and cam were changed but thats about all know. The noise doesn't seem to bother anything but it sure sounds terrible. Its quiet revved up high, I'm starting to think the push rods might be a tad too short...........the base circle on most aftermarket cams is smaller and most guys don't take that into consideration.

 

I have a theory that we're hearing more of these ticking/tapping complaints as a result of the recent reformulation of engine oils to include less zinc.

No data to support this theory, but with the fed/API mandate reducing the limit on zinc to 800ppm we seem to be seeing a lot more of these complaints.

Mine became noisy at idle this year also. I switched to another synthetic that had 1100ppm zinc, and no more ticking at idle. Just a data point.

 

Faster lobe ramp rates + stiffer springs = taptaptaptapaptap

 

I just got my cut-out on! No more tapping!!! CUZ I CAN"T HEAR NOTHIN BUT RUMBLE!!!:>)

 

I put the video in the external section. Give it a listen

 

What oil did you switch from/to ?

 

Same question?

 

I'm sure my tapping is NOT the valve train. I'm sure its an extreme case of piston noise because once its good and hot most all the noise is gone. But on a cold start or even a warm start if it sets a few mins it sounds like the worst clattering you could imagine. Its almost embarrasing to start with anyone around.

 

fixed

mine does the tapping when it revs down it sounds like a bunch of hail hitting the ground hard. but i think i still have the stock cam in it cant hear much through stock muffler. then i have the usual 5-10 min of piston slap on cold starts til it hits 180-210

i heard a rumor about the lifter trays wearing down causing a tapping too.

 

Very interesting and thanks for posting this op. I thought I was practically the only one around with this problem and was just waiting for my engine to finally fall apart or something. Mine too goes away after a few minutes from a cold start. I thought it was the lifters till I got them replaced and they still did it. *shrugging*.