I Confederate I

Alright I know I'm going on a crazy amount of posts about the same problem, but it seems to be baffling a lot of local mechanics. Everyone seems to have their own opinion of course, but no one can seem to agree.

Ok so far I've posted wondering why my 01 SS is making a valve tapping noise around 65 mph. It goes away when the car returns to idle. General consensus leads to a lifter problem. I still haven't torn into the motor to find out the state of my lifters, but I have stopped driving it. I just can't find the time right now to pull the heads. But here are a few things I have found out:
1. My #7 exhaust pushrod is *slightly* bent. So slightly you can barely see it. I dipped it in tranny fluid and rolled it on a blank piece of paper on a level surface and found gaps in the pattern it left.
2. My pushrod length is a good bit over the stock length (7.450) and that is .050 longer than TSP recommends for my cam.
3. The guy I bought the car from told me that he installed adjustable roller rockers, which was a load of crap. They are completely stock.
4. The guy at TSP (who was extremely nice) said that if my tapping is intermittent like it is, there most likely is not any damage to the cam.
5. I did find the time to go ahead and replace the spark plugs (it really needed it) and I noticed that my 2 4 6 and 8 spark plugs were really carbon fouled.

So, with this, does anyone have any suggestions that might point towards another reason I have this ridiculous tapping? Could it be caused by too much preload from the pushrods? I feel like the pushrods might be stopping a lifter from getting pumped up all the way, leading to my tapping. Once the car returns to idle, the lifter is getting the chance to get pumped up, and it stops. However, if my theory is correct, shouldn't all the lifters be tapping at some point? Or am I f*cked and I need to start ripping it apart?

Thanks so much guys, you are the best.

crainholio

iTrader: (2)

Right, let's measure your pushrod length for you over the Intarwebz...

vettenuts

iTrader: (4)

Any codes or other indications on why one bank appears rich?

What mods does the car have? Sounds like at least a cam.

Is this tapping recent or has it been doing this all along?

A single pushrod is cheap, buy one and replace the one you believe to be bent and work from there. You need to evaluate problems one at a time or it will become very confusing.

JUSTINSWS6

Did you replace the bent pushrod yet? It is not your cam or it would do it all the time. I would upgrade your stock rockers to the retro fit ones comp makes. And it only makes the noise at 65 or is it the rpm you are at at 65? What rpm are you at ehen cruising 65?

I Confederate I

It appears to happen at the rpm, not the speed. At 65 im running about 1600rpms. I can always recreate the sound at that speed, and its more difficult to do it at a different speed.

I haven't replaced the PR yet, but like I said, im not driving it. Just as a test I moved the bent one to a different cylinder to see if the noise moved with it, but so far I can't tell.
As far as mods, I've got a cam as well as a few minor ones, such as the SLP intake box, LT headers, MSD wires, and a exhaust setup. Im not throwing any codes, but my best guess as to why I'm running rich is my illuminated o2 sensors messing with my tune. Either that or a bad connection leading to that banks coil packs. It was brought up to me that my 2 problems could possibly be related.

JUSTINSWS6

Try to turn on the car and make a video of you holding it at 1600 rpm so we can hear the noise much easier to say what it is that way.

crainholio

iTrader: (2)

Thinking about this a bit more, the bent pushrod is not stock length and therefore likely an aftermarket hardened piece. If something happened to bend it, there is a root cause of the problem that needs to be identified and fixed.

Next step is a $20 Comp pushrod tool to get an accurate length measurement and see how far off the current pushrods might be.

If they're long enough that the lifters are going solid and causing piston-valve contact, you'll want to get the right ones...and do a compression test on the cylinder w/ the bent one to see if the valve got bent as well.

I Confederate I

Decided to take the car to RPM motorsports today and have them run a compression test. All 8 are running at 175psi, so no damage has been done. She did decide to cooperate on start up after the test however, and she started tapping. After a few tests, the guys at RPM came to the conclusion that I have a "lazy lifter" that isn't staying pumped up. So, lifter job it is. Thanks for the help guys, I really appreciate it. You helped point me in the right direction.

mark21742

Check this and report back... Lightly tighten your rockers to "0" lash, then count the turns from "0" lash to torque. Most setups "like" about 3/4-1 1/4 turns from 0 to torque...personally I found my setup works best at just a hair over 1/4 turn to torque but I don't have your "average" setup.

If your more than 1 1/4 turns to torque you need shorter pushrods and if you let us know how many turns you have we can pretty much tell you exactly what length you need since we have your pushrod length now...no need to go buy an adjustable pushrod checker.