Ok so my 90 mustang gt has a problem, it was making a slight tapping sound for a week or so then I changed the oil and it went away. So then a month later (now) its making a loud tapping sound. So I took the intake and valve covers off to check the pushrods/ lifters. And nothing is bent or broken. So what can it be. The motor is a fresh rerbuilt 5.0 with about 5,000-6,000 miles on it. So any help please! Thank you.

 

More info on the sound is required please. Do you have solid lifters? Or hydraulic? Are the heads rebuilt, new, or old? The rocker arms...are they new or old? Also, are the rollers? Or stock ball and socket ones etc etc.

I am inclined to think they are stock ones that are ball and socket type. And if so, you may simply have a bad rocker arm. It happened to me once....and when I replaced the rockers, poof....The tapping went away. Hope this helps.

 

Yeah there the stock rockers. With comp cams springs. And newly rebuilt heads. With factory roller lifters.

 

Like I said, I am inclined to think it would be a bad rocker ball....but without listening to it, I can't be certain.

 

Well how would I look and see if it were?

 

Is the sound coming from one side of the motor or the other?

 

It's pretty loud, Tim. It's a deeper sound that just a rocker arm being busted. You sure none of the lifter's were collapsed, JJ..?

 

Its on the driver side. Idk I have checked the roller on all of them and they were good what can I do to check if there pumping up or not?

 

pushrod will have preload if pumped up...if not, you will find a loose pushrod

 

I'm not saying a "broken rocker arm". I'm saying the ball of the rocker is not good anymore. I've had this happen before. And when you pull them all off to inspect them, they all look fine....put them back on, and the sound persists. Replace them one by one, and viola, the sound goes away with one of them being replaced.

If you had a collapsed lifter, like Tommy said, the rocker would be loose, and no way to tighten it up.

Is your valvetrain adjustable? (You said it's stock, which would indicate it's not....buuut....) I would like to listen to it sometime, but unfortunately, I am training this morning, and then this afternoon, I have a lunch date with a new girl. Sooo....Yeah...I MIGHT be able to drop by after around 3 or 4. PM me you addy and a phone. I'll text you if I can make it around then. That way, I can make a better diagnosis.

Who did the rebuild? Were the heads rebuilt also? Did they just do the short block? Or the long block?