^^^^ I'd do a little more research. Just give 'em some lame excuse untill you find out more.

 

But I'm curious if you guy have noticed that it's when the engine is cold or not totally warmed up at running temp.

Please reply
Lowflyingbird

 

Yea , that's what I would want to know for sure - Piston Slap ? What ?

Did you say it does have a Motorcraft PCV valve ? I think you did .

Only other thing that will knock is the EGR pipe itself - It sounds just like a knock when it's loose or leaking @ the threads.

 

Hello again,can you guys tell me if i remove those cats will it harm the engine? and if not, will the computer need a calibration?

 

The shields on the cats over 100k. always seem to come loose from rust and then tap against the converter itself with engine resonance/vibration. I simply can not count how many I have fastened or disguarded over the years. The sound is enough to drive you nuts.The sound is a metalic sometime deep sounding tick. I have never heard a converters internal knock, ever. By the time it would be diagnosed, I'd figure that it was done for, by being beat around in it's shell.

Now piston slap is what I believe my just built engine has. For the last few years, like 10. Ford and other companies as expected due to $$$ have been using Hyperutectic (probably spelled that wrong) pistons. Unlike regular cast pistons, and forged pistons which really expand alot. These pistons do not, due to a large amount of silicone in the aluminum. Manufacturers love them because just like those sintered metal (powder) rods, they are cheaper to make and can be balanced as sets easier. They are also stronger that regular cast pistons.

Worse is that to make engines more effecient , pistons have become shorter, sometimes eliminating the skirt all together. The 5.4 is a long stroke engine. So, the throw of the crank as it goes around is quite far. As it goes from one side down, to the other side and up, these short pistons rock back and forth slightly in their bore. When they do it makes a knocking sound,almost like having a diesel engine, or if worse, just like a bad rod bearing. When the engine reaches it's full temperature, the piston expands and usually the knock dissapears. However sometimes it can still be heard.

Lowflyingbird

LOCKHEED I just saw your post. I see your in Canada, so I dont know what your emmission laws are but, It will throw an engine code.

 

You ain't kidding , specially with your foot on the break in "D" . That freakin chirping WILL drive you nuts!

The damn heat shields are only spot welded at the factory which doesn't last forever.

I clamped mine - That lasted for a couple years. I ended up removing them after that.

 

You have two choices -

1. Gut your fronts cats.

2. Remove the rears completely and replace w/2.50 section of pipe.

You will remain within parameters (no check engine light)and still pass emissions that way.

I chose to remove the rears and actually liked that set up - It has a better sound - like a GT Mustang if you have a good cat back system.

Heres a pic of that set up when I went with it -