The only thing I can think to do is dig into it. I am patiently waiting for the weekend. I just put it some 91 to see if anything changes. I got like 288 miles on 3/4 tank ac on. I am not sure how big the tank is or if the gauge is right. I didn't fill it. I put in $20 or 5 gal. Rediculous.

Anyway, it is a very strange thing to me. The only reason I would not think it is the torque converter bolts or a cracked flywheel is because my room mate has a 04 e250 with a 4.6 and it has right at 200,000 as well, and because of the last transmission issue and the company had to rebuild it 3 times. It has that knock at idle. It sounds awful. But I know that its that because I can take the dog house off and hear it.

And to add on the way to work yesterday, I had to make a u-turn on the highway. (accident and I had to get to work) So I had to go when I went. So I did. I didn't quite floor it, because I don't ever drive my cars that hard. I went to around 4500 rpm per shift. And it went, and went well. Put a giant grin on my face. Didn't miss a beat. Temp is always perfect and oil pressure is about 5/8 all the time. I know its dummy lights but still. And almost putting 300 miles on it since sunday makes me really think its not a bearing. For some reason I am thinking cam guides. Like when the timing chain can put a load on the cam it is quiet, but when it goes to higher rpm, or the tension is suddenly released. Its starts to wobble. Kinda how I view it in my head. I plan to be gently with it, and will continue to update as I tackle this problem.

I appreciate the help!

 

Hello MrMech82 I am also an owner of an MN-12. Mine is a '95 T-Bird Lx with a 4.6.

In all honesty, from one owner to the next, the sound you've discribed gives all indication of a rod knock.

You see valvetrain componets tick. Cam chains slap right there at the front of the engine. Rather unmistakeable as it's easy to hear.

Now granted I could be wrong. I haven't actually heard the sound. However, from what you've discribed, I'd say, unfortunately, it's a rod knock. Big end bore where the rod attaches to the crank. If it has a double knock sound that is an indication of a piston pin and/or piston pin boss.

Main bearings will usually knock right upon start up. And usually at a broader range of the rpm spectrum than what you've discribed. And under hard launch. Usually.

And that's the clencher. Rods knock at that not so sweet spot just like you discribed. Along with run on three qrts. low on oil. Cavitation possible cause.

May I suggest having someone with experience in these sounds take a listen before you spend time and money on the top-end.

Hate to be the devil's advocate. Hope to see a reply. There are some other things I'd like to write, but I'll stop for now...

Got any pics of your Bird?

Or better yet, how about a sound byte of the knock?

 

I will try and see if I can get a recording off my phone. Somehow. Its to light inside the car for the mic to pick up the sound. maybe I can find a tunnel or something.
With the last day or so, the knocking sound is more present now at lower rpm at around 1700. But now the knock is quiet almost gone on harder acceleration.
The only reason I don't think is a main bearing is because the one time I could reproduce it, it sound like I could here it through the valve cover. Now about a wrist pin. I could see that being I feel it's higher up in the motor.
The thing is, I am really good at engine noises. Been a used car tech for a few years now and this one has me along with many of my resources dumb founded.
Because it is a knock sound. But not a dull knock. Its sharp, quick. Almost could call it a tick but not. That's kinda why I was thinking cam guides. Not so much the chain but the cam itself may have movement on the head. But because I am a tech I won't just throw parts at it. Or money. I have driven it over 300 miles now and although the sound comes at a little different time, the actual noise is consistently the same. Has not worsened or improved. And after 300 miles I would believe a bearing would have had to much friction and would worsen.
thanks for the help and input. Its Friday so the weekend is here. Once I get off of work at 5 its time. Its time to look within.
I also here your point about the low oil. That's the only thing that makes me think bearings. But like I said earlier. I feel like he took it to ford and they told him bearings or needs a motor and sold him a new car. Is what I feel. I would never have a dealer work on a 16 year old vehicle. They may have superior equipment but all there knowledge is for the last 5years of vehicles. Like the last time I brought a 01 powerstroke to ford for a contribution test and they ended up setting it on fire.

I will reply again after work and see if I can get some sound recorded and I can get a pic or two up. Thanks again!

 

Ok, so instead of doing engine work, I opted for body work. The reason I bought the car, very cheap, is because it was rear ended. Not bad, but enough to push the bumper on the exhaust. So this evening I did some tree work to it. Came out beautiful. Some wrinkling left of the passenger quarter, but the driver side came out almost perfect. So I was happy.

I am more and more believing it is in the head. After the hour long tree pulling experience with never turning the car off. I never heard the knock sound. And as of lately it has been a bit quiter. And it is just about silent on acceleration, only on decel and its only for a brief moment. Or lets say I am driving slow and it shifts, I will hear it for second.

Tomorrow is that day the valve cover comes off. After I get my heat gun out and make the bumper back to normal that is.

So my update tomorrow will be full of pics and new findings.

 

Just wondering if you have even thought to check the PCV? As I stated previously, we had one with a weak spring and it sounded just like a problem in the head. I know it is kinda stupid, but it is an easy and cheap thing to check.

 

I havent checked the pcv. Good Idea, I didn't take any pictures yesterday because of the rain. I just managed to get the rear end put back together.
I do however feel as though I am getting closer to the problem.

So after I pulled the back end out with a tree a new noise appeared the next day. I think it maybe in the transmission. In park there is a scratching noise or a vibration I can hear coming from the driver side. The moment the gear selector is pressed into reverse neutral or drive it stops.

So I have an appointment with buzz's muffler to look at my exhaust. The tail pipe or mufflers were bent into the rear sway bar mounts and I need a lift to be able to bend them back. On the ground there just isn't enough room to heat up and bend them back with my oxy torch safely.

Also yesterday I heard the noise on start up. For a brief moment. If its not the transmission then I believe it is in the head. I had a few "old timers" from the local bar take a listen and everyone on said its a tick not a knock. Its a loud and noticeable tick, but for it to be a knock it should "echo"? I dunno, but they all said it didn't sound like a knock.

Later today, after 3, I am gonna pull that valve cover. I have been procrastinating. And look. The locals said to run it with the VC off and see if I here some chattering. If so then they said to replace the HLA's on that side of the head. If that doesn't fix it, they said to pull off the back half of the head rocker arms and line them up and see if there is any distortion in the rocker arms. They also showed me how to remove them with out the tool.

So I look forward to that and will update as I go. Maybe it is just in my transmission and that I don't care. I can R and R a gm 700r4 or 4l60e and ect in a day. And ford's are always easier IMO. Thanks. for the help, and I will look into the pcv.

 

The tranny is a (old) 4R70W, which is the last (THANK GOD!) version of the old AOD. Torque convertor knocks were common on these, and I would worry a bit about it, as it usually means that the thrust washer for the TCC clutch is wearing out. It's bronze, and they tended to do this, which would eventually take out the trans. They're easy to take out.
Good luck, and mr. thexlo8ers made a good point about getting someone with experience to listen to it. Keep us posted!

 

Ok so after many many hours and days on youtube, this is the closest I can find that sounds like my sound.

Now, unlike the video mine does not make the noise at idle, but the way it goes away when he revs it and comes back it is close to my sound. Mine is not that loud and you can't here it parked.

 

From the sound of it I will say the car in the video has a defective hydraulic lash adjuster, follower, broken valve spring.

Sound is coming from this area of the engine...

http://image.mustang50magazine.com/f...2Bport_job.jpg

Diff. not a knock. It is a tappet noise.

 

So here is an unpdate. Its been a while. And after digging into the valve cover and everything, it is coming from the transmission. I believe it is the anti-rattle clip. Or an issue in the toque converter. I talked to a couple of transmission shops and they all said it could go or it can make that noise forever. So its just an unknown. So at this point I plan to just drive it.