Friend's 98, muffled slap sound. Updated findings...

[LJRuddy]

Today while going to work, my friend noticed a muffled slapping sound (similar to a serp. belt shredding its way into threads). He messaged me and I decided to meet him for lunch to take a look at it. As he started it up, i started probing around the engine with my torque wrench to my ear to narrow the sound. The noise is definitely coming from the passenger rear of the engine bay. At first I thought it might have been a cam on its way out but the sound is not so much a ticking as it is a muffled slapping sound. However, it definitely sounds like metal on metal friction. Some of the things I thought of were the alternator, P/S pump and maybe the timing chain. My friend says that he is 95% sure the cams were welded by the P/O. For the record, he has had the car since it had like 90k on the clock. It now has almost 170k.

The engine runs AND idles smooth and the power is very linear across the rpm band which, for me, makes me doubt the cams are spinning. There is no ticking coming from any other part of the engine. When the weather warms up, i am going to pull the serp. belt off and see if this solves the problem.

Here is a quick video that we took in the parking lot before he went back to work. You can really hear the sound at around 19 seconds and it gets even louder at around 25 seconds. The noise seems to go away (or at least become muffled by the engine) at rpms higher than idle. When the engine is cold, the noise seems to be either non-existent or too quiet to hear from inside. As it warms up, the noise will come and go with it sometimes being louder than before.

Whaddya think, SHOForum?

 

[ruWelded]

Bad Noise

That sounds awful, I would not run it very much more until you find the problem and fix it. This does not sound like the ticking I had with two loose cam gears. The first thing I would look at would be the cam chain tensioner. It has two nylon pieces that the chain rides on. The current project that I am working on had one of these pieces broken, so the chain was riding metal to metal. It could also be a bad pulley, use a mechanics stethoscope to try to pinpoint the location of this noise.

 

[1993MTXSHO]

i dunno, but passenger rear, isnt that right where the cams snap on the rear head where it pulls outta the sprocket. Id not start that engine again until you pull that rear cover or get some other insight as to what it might be, that sounds like a cam flying around to me, but then again i dunno much about the v8 sho.

 

[E1 v2]

It's WAY distorted.
Kind of like when people call me up and hold their cell phones under the hood and ask "Can you HEAR that"? It just never seems to work. Could be cams, could be a rod bearing, could be a clogged catalytic converter causing backpressure and knocking, could be a chunk out of the accessory belt.

Just can't tell.

I'd definitely take the opportunity of a weekend to lift off the valvecovers and look closer, if nothing else.

Doesn't sound good, whatever it is.

 

[stephen newberg]

I am with Brad. To me that sounds of a cam chain tensioner assembly.

pax, smn

 

[LJRuddy]

Now where would we be able to locate a cam chain tensioner assembly and how much of a job would i be getting myself into?

The past few times I've worked on this car ended up badly. I changed the starter on it last winter and while my finger was in the process of freezing itself off, i dropped the started onto it and made an asphalt, finger, and starter sandwich. Then, as I was changing the lower radiator hose, I began to become insanely sick. Barely made it out of the garage before I began vomiting the ABC's.

This car does not like me and Im kinda worried what kind of spell it might put on me this time. :worried:

 

[ruWelded]

Tensioner on E-bay

Ray has several on e-bay right now.

Here is one link: http://cgi.ebay.com/ebaymotors/96-9...262QQcategoryZ6763QQihZ011QQitemZ320157292082

Shoot him a best offer.

If you look at the picture, on the bottom nylon piece, it looks like it has rivets. That is what broke on my engine, the bad thing is to locate all the pieces. Some of mine were still in the head other pieces were in the oil pan. Any way for me this engine was trashed by lack of oil changes. I am replacing it with a low mileage one I had already.

If you need to replace the tensioner, you will need to squeeze the top and bottom together. If you look at the picture of Ray’s, notice there is a hole in the center of the top nylon piece. This is so when it is compressed together you can stick a piece of wire in the hole to keep it compressed for removal and installation. The tensioner is mounted to the head by two small bolts. It’s not a bad job once you get the intake off. But I would not want to do it outside on a cold day.

 

[SHOZ123]

I would first take the belt off to see if the noise disappears. If it doesn't then I would take the valve covers off to see what's up there. Then chain tensioners.

 

[stephen newberg]

I would first take the belt off to see if the noise disappears. If it doesn't then I would take the valve covers off to see what's up there. Then chain tensioners.

That is good advice. Might as well check from easy toward difficult.

pax, smn

 

[LJRuddy]

We have narrowed the search down to one thing... Cams are welded and in good shape. Accessories are all good and the cam chain tensioner is operational. The sound is coming from the balance shaft. I have never heard of these going bad. What might cause them to break? Are there any replacements out there? Cost? How tough of a job is this to complete? Do i need to pull the engine out?

Anyone somewhat close to KC who would be interested in helping with this (we will come to you) wanna PM me with their availability and prices?

 

[ruWelded]

I think Ray has a balance shaft for sale, so you could look at his pictures. The balance shaft has a front and rear bearing, I suppose the front might be bad. I don’t think the shaft itself has broken it looks pretty stout. To get to the front bearing and the shaft, the front cover will need to be pulled. You can do that in the car, but it won’t be easy. Also if you need to remove the balance shaft, it might not fit past the car body. Another thought is, if you remove the oil vapor separator you can see several inches of the balance shaft. I wonder if something could be rubbing in that location. How were you able to decide that the balance shaft is the culprit? Other things on that side that could be the problem are main timing chain, chain tensioner, chain guides or main belt pulleys. None of this stuff is easy to get to, so I feel your pain.

 

[LJRuddy]

I think Ray has a balance shaft for sale, so you could look at his pictures. The balance shaft has a front and rear bearing, I suppose the front might be bad. I don’t think the shaft itself has broken it looks pretty stout. To get to the front bearing and the shaft, the front cover will need to be pulled. You can do that in the car, but it won’t be easy. Also if you need to remove the balance shaft, it might not fit past the car body. Another thought is, if you remove the oil vapor separator you can see several inches of the balance shaft. I wonder if something could be rubbing in that location. How were you able to decide that the balance shaft is the culprit? Other things on that side that could be the problem are main timing chain, chain tensioner, chain guides or main belt pulleys. None of this stuff is easy to get to, so I feel your pain.

Everything looks to be in good condition. All of the tensioners are in excellent shape, the cams are welded and the sprockets are on straight. The engine still made the noise with the serp. belt off... And I was able to narrow the noise down to the valley of the engine exactly where the balance shaft is. Anyone know if I can still buy the bearings for these? Once these bearings go out, can I just slide new ones in? Or do I need to buy a whole new assembly?

 

[LJRuddy]

Bump...

Anyone??

 

[SHOZ123]

The balance shaft needs to come out with the engine out of the car. The Ford V8 tool kit includes the tools to do this. I'm sure you can come up with used bearings and a balance shaft from some one.

If the timing cover and chain is out you can easily turn the balance shaft and should be able to notice if there is a bad bearing or not.

Here's a pic of the balance shaft as seen through the oil separator opening under the LIM.



Here's a pic of the front of the block where you can see the front balance shaft bearing.



Here's a pic of the front of the motor with the timing chain installed. You can see how it drives the shaft.

 

[hawkeye18]

WTH is a balance shaft? I mean, I'd assume it... uh, balances... stuff.. but what exactly is its purpose?

 

[LJRuddy]

WTH is a balance shaft? I mean, I'd assume it... uh, balances... stuff.. but what exactly is its purpose?

It counters the vibrations of the engine to make it as smooth running as possible. Just like a harmonic dampener pulley.

 

[SHOZ123]

Because of the 60 degree piston orientation.

 

[quickfix4u]

having the same problem

wow I'm having the same sound just the other day
it started with my battery light coming on first then my speedometer's just stopped working then i heard a crackling sound from my speakers then it worked fine. then i heard the sound only when I'm idling

 

[quickfix4u]

fixed my problem

well guys it was my alternator
now i m having the hardest time
trying to reinstall it
can get the Belt Tensioner up to put the belt on