My engine sounds Horrible

[Grandmaster]

Ok guys, my engine sounds horrible. It sounds like a machine gun or something. There is a constant knocking sound that is fairly loud, and it is very fast, and varies with the rpm. Its not a slow knock, a fast one, real fast. I dont have the money to take it to a shop right now, but if someone could list most of the probable causes and how i might be able to pin point it thta would be great. As it is i can tell it is coming from the engine and that is it, i cannot distinguish from what area it is coming.

Thanks.

 

[281pony]

check for exhaust leaks around the headers/collectors, any air leaks, otherwise could be lifters, roller rockers, many things.

has to be some way of distinguishing the area its coming from. have a stethescope?

 

[stang22]

The first thing I would check is for exhaust/header leaks. Double check all of your header bolts to make sure none of them backed out. The next thing it could possibly be is valve train. I.e, a bad lifter, broken spring, broken rocker etc...

Have you noticed any difference in the way it runs since it started making this noise?

Tim

 

[Aliate X]

It sounds like you have an ignition knock, pretty easy fix, you just need to retime the car.

 

[Grandmaster]

The car runs great, pulls hard like normal. However, It has trouble on startup. The first time i start it after its sat for a while, like overnight or most of the day, if i start it and dont get on the gas it will die, and if i start it again it will die, over and over, until i give it some gas and keep it around 1500rpm for maybe 10 sec, then it will be fine, exept for it surges. At idle it dips down to about 500 rpm like it wants to die then surges up to 1500 then back to 500 then to 1500 etc.

So, while its running, its great, but when at startup, ewww.

I know for a fact that i have exhaust leaks, cause i can hear it, but i didn't realize that an exaust leak could sound like THAT. I'll go check it out, because now that i think about it, it definitely sounds like it could be around the header.

Thanks for the help thusfar, any more based on this new info is greatly appreciated!

 

[281pony]

exhaust leaks can be a real pain in the ass.

do you have a code reader? surging idle may or may not be related. probably wouldnt hurt to clean your iac/tb/maf, set timing, ect as well.

 

[stang22]

Check your TPS voltage as well. Another overlooked item.

Tim

 

[fordman54935]

I bet his timing is too far advanced, which would explain the pinging and hard starting. Its worth checking anyway.

 

[ExplodingGopher]

turn your dizzy CCW very slightly and see if it goes away. Probably your ignition too far advanced. If that doesn't work, it could also be a collapsed lifter amking your rockers knock, thats what happened to my 5.0, it sucked. Or also could be a rocker thats too loose, just make sure the nuts are all tightened down.

 

[Red89Notch]

Ok guys, my engine sounds horrible. It sounds like a machine gun or something. There is a constant knocking sound that is fairly loud, and it is very fast, and varies with the rpm. Its not a slow knock, a fast one, real fast. I dont have the money to take it to a shop right now, but if someone could list most of the probable causes and how i might be able to pin point it thta would be great. As it is i can tell it is coming from the engine and that is it, i cannot distinguish from what area it is coming.

Thanks.

Rod Knock
Valve tap
Exhaust leak

 

[txstang84]

i think all the typical noises have been addressed...

but usually true "knocking" is a lower end noise, or as mentioned spark knock-but not usually at idle...typically speaking-detonation only happens under load, although not every situation is the same, which the hard to start lends creed to that as well. again typically speaking, high initial timing will also cause the start to sound very "labored" and almost like the starter is heat soaked, like a chevy-that slow "wha....wha....wha" sound

...if it sounds like a sewing machine on steroids, then you've most likely got some valvetrain issues,

...if it sounds like a muffled popping noise, then exhaust leaks are a definite possibility