Low RPM "rap" from rear valve cover

[Dr.Evil]

Well I changed the bearings out like everyone here said I should... what a bad idea that was! To start things off, every single exhaust stud snapped off. I spent about 5 hours repairing that, and it still isnt quite right. Beter yet the "rap" is still there, same exact noise, hasen't changed a bit. And to top it all off I've aquired a whole new taping sound that was'nt there before. What a nightmare this has been, mostly beacause of the exhaust, even more now because its still broken.

Check to make sure your timing belt is tight. It could be slaping the cover causing a weird noise. This happened to me last week. I couldn't find it until I poped off the upper timing belt cover and found the bent was loose.

As for the new tapping, could it be an exhaust leak?

 

[F-22 Raptor SHO]

1: More diagnosis and zeroing on the problem before you start taking more stuff apart. Simply replacing crap because people said to do it isnt a good idea.

Noise top or bottom? WOuld tell you if it were the bearings or the cams/chain.

Noise left or right? this would help with chain tensioner or timing belt.

noise front or back? this would tell you what bank is giving you the trouble.

Raps can be many many things

Rod bearings
Timing chain or tensioner
Timing Belt
Valve shim out
bad wrist pin
hole in cylinder wall or piston.

You found a problem when you had the top apart I would continue on that line...the cams were taken out or at least it appears they were. Did you check the lash while you were in there? What did it look like?

Dont just start taking stuff apart without evidence.

 

[Rockledge]

Checking (and replacing while in there) the rod bearings was well worth your time and effort, IMO. You have now ruled out the rod bearings as a cause of the knock, which means, among other things, that your engine is still worth keeping. Had you found a spun bearing, the diagnostics would have stopped right there. The fact that you had some difficulty dropping the pan does not diminish the importance of ruling out a spun bearing as a cause of the knocking.

Sometimes things have to be taken apart in order for proper diagnostics to be carried out. No getting around it.

 

[SleeperStyle]

Well tommorrow I'm going to take the timing cover off and inspect in there. When I first heard the noise my instincts told me water pump. After posting in here everyone kept saying rod bearings, and after some more research I learned just how fragile they seem to be in these motors.
The bearing job would have been about 5-6 hours had not every manifold stud decided to break. My exhaust is now "rigged up" as I got irrate and made it work. So instead of 5-6 hours, it was more like 10-12 hours of work.
Regardless of all that they were in need of replacement. Actually when I saw them I was almost sure that it was the problem. Well tommorrow is another day.

 

[SonicRiot]

Sucks man. Once a couple of buddies and I told this other guy that the noise coming from his car was his muffler bearings. Took him a couple of hours to figure out that one.



Just goes to show, you have to be careful who you take advice from. Also, be sure to be thorough in your explaination. It is very difficult to diagnose a car over the internet.

 

[Dr.Evil]

It could very well be the water pump bearings. I bought a cheap civic SI and the motor sounded something was tapping/knocking inside. I assumed it was the rod bearings. Well the pump started leaking, and then the timing belt snaped. The water pump literaly ceased to turn.

Just try taking the belt off and spin it by hand. If it feels like it is grinding or not turning smooth, that just might be your problem. (or at least one of them)

 

[SleeperStyle]

I found the problem tonight. I took the top of the timing cover off and started her up. You can see the belt flaping all around at an idle. Looking more closely I saw the pulley/tensioner on the left side is also flapping all over the place. There are marks on the timing cover from where it was hitting it, and the noise has stopped with the cover off.
So I called the dealer to price a tensioner, and he stated that his diagram shows it (the tensioner) is in the middle of the belt not on the outside. So I'm wondering if it's the tensioner or just a guide pulley? Anybody know what this pulley is, it appears to be a tensioner to me. There is also one just like it on the right side of the belt.
Help me out so I can spend some more money
Well, I'm only into the whole car for about $550, so I really can't complain.
Here she is the way I found her.

 

[SHOtimer]

The ATX timing belt has two pulleys, one is just an idler pulley the other is a tensioner. The tensioner is on the rear side of the motor, (the side closest to the firewall). If I remember correctly the tensioner simply pushes on the pulley to bring the belt to the proper tension. So, you just need the tensioner, which also I believe is discontinued. So, I would post in the
WTB section, or look in a junk yard. Their is a lot of 3.2 swaps out there so i'm sure their are plenty of tensioners.

Doug

 

[Dr.Evil]

I found the problem tonight. I took the top of the timing cover off and started her up. You can see the belt flaping all around at an idle. Looking more closely I saw the pulley/tensioner on the left side is also flapping all over the place. There are marks on the timing cover from where it was hitting it, and the noise has stopped with the cover off.
So I called the dealer to price a tensioner, and he stated that his diagram shows it (the tensioner) is in the middle of the belt not on the outside. So I'm wondering if it's the tensioner or just a guide pulley? Anybody know what this pulley is, it appears to be a tensioner to me. There is also one just like it on the right side of the belt.
Help me out so I can spend some more money
Well, I'm only into the whole car for about $550, so I really can't complain.
Here she is the way I found her.

I thought that was it. It was probably making the same sound mine was:

BTW you can get a new tensioner at kragen for 69.99. Ill find the P/N and post it later.

 

[SHOtimer]

BTW you can get a new tensioner at kragen for 69.99. Ill find the P/N and post it later.

Are you sure this is an ATX timing belt tensioner? To my knowledge this is a Ford only discontinued part. Just because Kragen has a part number doesn't mean the part is accurate. But, if they do I will be impressed and relieved that another discontiuned part is still available.

Doug

 

[Dr.Evil]

Are you sure this is an ATX timing belt tensioner? To my knowledge this is a Ford only discontinued part. Just because Kragen has a part number doesn't mean the part is accurate. But, if they do I will be impressed and relieved that another discontiuned part is still available.

Doug

I didn't know he needed an ATX tensioner. I did however get one for my MTX.

 

[SHOtimer]

I didn't know he needed an ATX tensioner. I did however get one for my MTX.

Yea you MTXers always get taken care of....

Doug

 

[SleeperStyle]

It is an ATX, and the dealer (Tasca Ford) told me they could get one S.O. for $110. I guess it would probably be a good idea to replace the belt while I'm there, or can I replace the tensioner without removing the belt? The belt doesn't look to bad, although it may be bad from the beating it been getting.
I'm kind of tired of taking it apart, and would really would just like to drive the damn thing. Funny, when your car is down for performance work it's o.k. but when it's down for repair it really sucks.

 

[SHOtimer]

If you don't know when the belt was last replaced and you will be replacing the tensioner anyway you might as well replace the belt for an extra $35. Use the Gates belt from Rockauto.com. It has the proper lineup marks to orient it, as the OEM one does not. Most people use and have no problems. I wouldn't suggest getting that far into it and not replacing the belt as it is right there and has taken quiet a beating.

Doug

 

[Sho-N-Go]

You can actually change the tensioner by just taking the dampner off and the lower cover. it is fairly easy to do. If you dont want to change the belt

 

[mrclean]

I have to say, even though you do have the engine knock, that guy was nuts to give that thing away for $350, that thing looks amazing.