OK, I am not sure how many of you saw my posts recently on getting the throttle stuck and bouncing off the rev limiter... Here it is if you didn't, but it went a little off topic...


Well I was wrong there is a problem, not sure what though

I went into making sure everything was OK with it last night, took it for a test drive and all seamed decent, but I could hear a faint tapping, but there was no missing or anything. I did full throttle through 1st gear, and then let off, as I let off I heard the tapping had gotten louder. I went for a slow cruise and let the revs rise and fall slowly and damnit there was a pretty loud tap now.

I went home and I took the vavle covers off, BTW I'm getting pretty quick at that now that I took have the factory crap of the car

The drivers side sounded good, but the noise was traced to the Passenger side. I looked at everything and didn't see a problem, I even verified that rockers were tight and didn't loosen up, even the one that was the loudest I loossened and reset to lash and it still made more noise then normal. What I did notice on 5 of the pushrods on the pass side when I rotated then to see how loos they might be they rotated with a little less resistance then before, not much but a little less, and there was a slightly springy metalic ting-like noices as I rotated them.

So today I need to figure out WTF happened...

What should I look for?

I was planning on pulling each of the pushrods out checking foranything being bent, warped, or mis-shaped. If they are good re-lashing everything again. What else could I do?

Is there a possibility of a bent valve, and if so would there be any signs without pulling the head and dropping the valves for inspection? There is no misfire that I am picking up on so I think I could rule that out right? I hope

Anyhow, thanks in advance for any info you guys have...

 

I had read your previous post and I know this is going to sound too simple, but...

Did you check for an exhaust leak? Maybe a header/manifold bolt vibrated just a little loose during your ordeal... That would cause a tapping noise coming from the same area...

Just a thought...

I hope it isn't anything major...

 

Good suggestion, that is something I can definitly check, Thanks...

 

That's exactly what I was going to say! I thought I had a tap and found the header gasket was leaking......on the passenger side! LOL
Mike

 

Mine was tapping recently, so last night i tightened up my headers and VIOLA, no more tapping! BUT my problem was a little different than yours. When I'd downshift or let off the gas the tapping would be gone. I'd only hear it when i give it gas. So I'm not even sure yours is an exhaust leak. Kinda sounds like a bad/loose rocker or something

 

Header bolts were good, and there are no leaks, but I found something interesting, not sure if this was the cause of the noise or not, then again not sure what to do to fix it either???

When I pulled the nuts off the hold the rockers down so I could check the pushrods I saw the following:

5 of the rockers on this side had a little damage (yellow circles) I will show 1 an 2 closer below...

rocker 1 from image above

close up view of rocker 1 from image above

rocker 2 from image above

close up view of rocker 2 from image above


BTW, the pushrods were all good and had nothing wrong with them...
WTF, any suggestions???

 

OK I think we can disregard the images above, I think I figured out what caused that... It looks like when I used and open end wrench to hold the nut still while tightening the poly lock, I wasn't watching the wrench and the rocker smacks it a few times, I guess this happens when you set lash while the engine is running, I just did it to another one while relashing so that's how I figured it out...

 

I would do a leakdown and compression test. Then the next step in my mind would be to pull the oil pan and check for a spun rod bearing.

 

no need for all that, I know what spun bearings sound like plus I know it's coming from the top end since the sound get much louder if I take the valve cover off, plus my stethascope (sp?) keeps telling me its more to the topend...

Now a compression/leakdown test might be in order if there is a bent valve, so I will keep that in mind, thanks...

 

OK I relashed everything and they quited down, these things are pretty finicky, I think I might be a little down on power because they won't stay quiet till a little past 1/4 turn...

To lash this pain in the butt rockers, I had to go till it stops tapping then about 5/16th turn and lock them down, funny thing is though right about at the 5/16th mark, I also hear a very slight change in the idle, so I think they might be hanging the valve open slightly, what do you guys think?

 

Earlier you said you heard a slight metallic *tinky* sound when you rotated your P-Rods. Maybe you had a lifter or two fail. Not going to say for sure since pulling those means pulling the intake too, but it is worth investigating.

Also, if while you were relashing the valves like you said and you heard a change in the idle, it is very possible that you've gone to far and are having the valves hang open a bit.

 

OK, I finally have an update...

It has been a while and I have done a few other little things to the car while I was iritated with trying to figure out what was going on with the tapping. That list includes refreshing the tranny (CPT's refresh deal is great ), Poly mounts (Motor, Tranny, and TA), OVC wires, clearancing the undercarage for the Pacesetter ORY, and a little more weight reduction.

Well after getting those projects finished up I took it for a test drive again, and it feels good but the tap was still there. But with the help of my new OVC wires I found the source of the tapping pretty quikly... With the motor running I was looking over the engine bay and the number 1 plug wire was shaking a little, after moving to see the plug I saw that it too was shaking in and out per each power stroke to that cyl ...

I have been racking my brain trying to figure out this tap for a while to find that it was caused by a loose sparkplug, ARGH!!! And ever worse then that, I installed new plug wires and didn't even notice it was loose ...

But hey the car is now running decently, and hopefully soon I can get to the track and test out the new mods since the last time out. I wonder if the new exhaust (LT Headers, ORY, and dumped after a bullet muffler), 1.6RR's (new springs, retainers and all), LT4 KM, Poly mounts, tune-up (new plugs, wires, and etc), and about 50# of weight reductions will get me to mid 12's on 2.73 gear ...