My noise, again?!

[Anonymous]

Well, I finally got the carburetor swapped performed this evening and drove the 'stang for a bit. I couldn't be happier! Seriously! The carb. swap has been the best thing for this car since I purchased it almost 2 1/2 years ago. BUT...(yes there is always a butt LOL)

I'm still experiencing a knocking sound (shop confirmed it's not an exhaust leak).

I changed out all the lifters today as well - nothing. Sure, it quited down tremendiously but it still knocks. Especially if I set my initial advance past 10 degress.?!

The sound is definetly coming from the block. I purchased a stethascope (sp) while I was out buying the lifters. It's louded around number 2 cylinder. But I can hear is on #1,#2,#3 and #4. #5 and #6 are quite.

I don't have roller rockers but stock rocker arms. New rods, bearings, pistons, valves, etc. Good compression - average out the 140 psi. Nothing more than a couple of pounds between all of the cylinders.

Could it be bad springs? I mean I never replaced those during the rebuild. I'm thinking too much slack?

Any ideas?



-Chris

P.S. I'll try and get an audio recording tomorrow. Maybe simon can help with posting it.

 

[Anonymous]

congrats...i am still saving. I am being nickeled and dimed everytime I try to save
congrats congrats

 

[Lazy JW]

Weak valve springs will give trouble at higher speeds but it's unlikely that they would be so bad as to cause trouble under no-load while listening with a stethascope. Try pulling one plug wire at a time while listening to see if the noise goes away on any particular cylinder. Also verify if the timing marks are correct.
Joe

 

[Anonymous]

lets hope it is not a "knock"

as that maybe be worn bearings...

 

[Anonymous]

lets hope it is not a "knock" as that maybe be worn bearings...

Yes, but he replaced the bearings.
Could also be a valve clearance issue.

 

[Anonymous]

Could it be the camshaft? It is the original cam.



-Chris

 

[Anonymous]

we both replaced the bears and NOT the camshaft...

in hindsight...I wish had doen the cam too!

 

[wsa111]

Chris, sounds like a worn wrist pin, cracked piston, is it worse cold?
If you crank the initial advance to 25-35 degrees to magnify the noise, then pull 1 plug wire at a time to try to find what cylinder it is. Thats why i hate cast pistons, they will not take any abuse.
I am going to put a new set of pistons in my 200 when i do the cam & cylinder head upgrade. My piston noise started after running the car on a chassis dyno. Let us know what you find. Good luck william

 

[Anonymous]

It sounds the same cold or warm. I'll pull the plugs tonight and report my findings tomorrow.

Thanks again guys for the help. I really would like to find the problem - quickly.



-Chris

 

[BIGREDRASA]

If the fuel pump is worn, it will make that kind of sound too. Try loosening the fuel pump and sliding it out about 1/2". If the sound changes (before the carb's bowl empties), then you'll know.

 

[Anonymous]

Cool, I'll try that as well.



-Chris

 

[wsa111]

Chris, Tony suggested a good idea. Just pull the fuel pump out & check for a broken arm return spring. I had this happen on a small block chevy about 15 years ago. Can't lose by just looking. william

 

[Anonymous]

hmmmm

pumps are easy to replace...why not just replace it anyways

I think I am gonna do that too

 

[Anonymous]

Okay, here's the latest.

I trying bumping up my intial advance to approx. 24 degrees and the sound did not change. Still resounding at the same level. So I lowered my timing to stock specifications approx. 6 degrees. Nothing, but the ticking sounded much slower. Next, I tried removing each reach spark plug - one by one. Nothing.

This lives me with the fuel pump as Tony suggested. I bought one last night and will try that this afternoon.

Also, I've noticed something new (maybe I should post this seperately) but I think I am experiencing valve float.

At about 3200+ rpms, my valves sound like they are floating (that's the only way I can describe it - previous experience with '67 F100). I mean it just doesn't sound smooth. It almost sounds like alot of marbles are rattling around in the head - at the valves. It runs smooth but sounds rough. Make sense?

The valves are new and I have stock rocker arms torqued to 40 lb/ft. Ideas on this one, anyone?

 

[Lazy JW]

Your valve springs would have to be almighty weak to actually float at 3200 rpm. And it doesn't run smooth when they do, either. Sounds more like pinging/detonation from too much advance.
Joe

 

[BIGREDRASA]

If your pump is not putting out enouogh fuel, you could be running lean, which can cause preignition, AKA "pinging".

 

[Anonymous]

Okay guys...the latest.

I still have ticking, clicking - whatever you want to call it and I'm almost at my wits ends. Think I'm just going to live with it - for now.

I changed out the fuel pump this afternoon - no change.

So, we've eliminated the following:

main bearings
valves
lifters
exhaust gasket
fuel pump

Anything else? Rods maybe?

I'm going to take a short video (with audio) maybe this way one of you guys can say, "ya, it's your transducent reluctor duplicator, DA!"



-Chris

 

[gtm1086]

Try taking the valve cover off and running it. to see if your noise goes away. You may have a rocker that is one loose"out of adjustment" or it maybe hitting the valve cover. Also the noise you are hearing at 3200 sounds like pinging detonation from too much advance.

 

[Anonymous]

someone once had an oil pan with a slight dent that was being tapped....

any dents in your pan?