Any idea what what's causing this noise?

[Mike681]

Update: Any idea what what's causing this noise?

UPDATE in Post Below: Hey guys, I posted on here a month or so ago needing some help diagnosing a noise that I thought was coming from my KB 2.2L. After having KB rebuild the supercharger, the noise is still there and obviously coming from my engine. My car has been at the shop for over a month now, and the guys "aren't 100% sure it's rod knock" and that it could be piston slap, neither of which are good, but they feel it is coming from lower engine. Today they are doing leakdown and compression tests, so hopefully that will tell us something.

That said, with listening to this video, what do you think is causing the sound? Of the dozens of rod knock and piston slap videos I have watched, my noise sounds like NONE of them. Notice that the noise comes and goes and is not constant. Also, turning the volume down on the video some helps clear out some of the surrounding engine noise.

My Cobra has custom fit Diamond pistons, Manley rods, and is bored .30 over.

Now for the video (sorry for the poor visibility as I was in my apartment's garage):

Cobra Noise - YouTube

 

[4to8]

timing chain slap maybe ?

 

[Mystic03]

what is: timing chain

 

[NELCO]

It sounds like a bearing failure that is intermittent.Nelco

 

[Mike681]

It really doesn't sound like a timing chain issue; it's more of a hollow kind of noise.

Nelco, bearing failure would be intermittent? Interesting and good to know because I haven't found one noise while searching/researching that is similar to mine. Most common responses have been valve guide, rod knock and piston slap.

 

[SNK-BITE]

Repost from your other thread. I hope your shop is going to pull the valve covers tomorrow.

Pull the valve covers!!! Thats not a rod knock. There been two threads in the last month on people having rockers poping off. You might have one laying in there hitting/binding with another one.

 

[Mike681]

I'm going to push them in that direction tomorrow. I also think I'm gonna need an entire head rebuild. FML but it could be worse, right?

Thanks for noticing both my posts haha.

 

[NELCO]

Mike, I think you have a blower belt bearing thats failing.. That's what i meant in my first post.. tensioner or idler
Nelco

 

[Mike681]

Nelco, I just had the entire blower rebuilt by KB. Now for the coincidence, the noise did start only shortly after I installed my Metco idler pulley set and a 3.5in alternator pulley. Coincidence or something else completely ******g up?

 

[JSTBCUZ]

Easy way to rule out any of the pullys on the supercharger side is to remove the belt and run the car without. It's really amazing how quiet the engine gets with that belt off.

 

[Mystic03]

^+1 i gotta do that tomorrow i heard a clacking upon startup but quickly went away i think its my kb..

 

[SNK-BITE]

Easy way to rule out any of the pullys on the supercharger side is to remove the belt and run the car without. It's really amazing how quiet the engine gets with that belt off.

OP said in his other thread that his shop ran it with the belt off and it was still there.

 

[Mike681]

^+1 i gotta do that tomorrow i heard a clacking upon startup but quickly went away i think its my kb..

Lol thought it was my KB at first and had it rebuilt (good peace of mind I suppose) but the thing was just fine. As long as you don't have any play in your sc pulley or other foreign noises you're fine. How many miles are on it?

 

[Mystic03]

Lol thought it was my KB at first and had it rebuilt (good peace of mind I suppose) but the thing was just fine. As long as you don't have any play in your sc pulley or other foreign noises you're fine. How many miles are on it?

ive had this noise for a while it comes n goes it only does it every so often. ill get done driving it let it sit for about 30min to an hour and ill start it up hear clacking then it free's up the blower is old first gen with prob 40-50k on it and does have a little bit of rotor play that i could hear when turning the pullie but still holds boost so dont fix if it aint broke! lol.but to relate it to your problem mine has zero noises like in your video i just started mine up lookin for sounds and could not find any

 

[Mike681]

So my shop emailed me today with this news and remedy to the situation:

"Hey Mike we got to a quiet area to listen to the 2 main cylinders that are low. It’s below past the rings into the crankcase. It’s definite the pistons are loose by the noise it’s making. You do have decent compression so the car is driveable, but it’s not the best way to keep it. Since the car is already bored .030 over or more since it was redone, my guess would be it wasn’t done correctly or it was beaten hard to do this. I would suggest a fresh block because of the issue."

So my big questions are:

1. Do you guys feel that I could and/or should continue driving this car the way it is? I don't exactly have a ton of money sitting around.
2. Should I spend another several thousand dollars for a new block? I've already spent quite a bit so far with everything else I've had done.
3. What are my other choices, if any? (aside from selling the thing)

I've already got 30% leakdown on two of my cylinders, so might it be better to bite the bullet and have everything redone? As opposed to risking it and having everything blow up down the road.

Thanks in advance.

 

[SVTmojo]

Keep us posted....