Knocking noise fix?

[1984rampage]

I began working on my 87 shelby z today. I meant to take a video so you all could hear what Im talking about but I forgot my camera.. There is a knock that is audible when I rev the engine. The previous owner told me it might be the rod bearings but Im not so sure as it seems like its coming more from the back left of the engine and not so much the bottom end. Anyone have any ideas? Im guessing a video would help, so Ill upload one tomorrow!

Thanks,
James

[Vigo]

Easy thing to start with:

Unplug the plug wires one at a time (i.e. run it with only one cylinder unplugged at a time) and rev the engine. IF it goes away or becomes much quieter on one cylinder, you've narrowed it down to a rod or wristpin, rod bearing being the most common thing.

[1984rampage]

Alright guys I took some vidoes! Let me know what you think... Vigo, I tried what you said and the knock did not go away or even become noticeably quiter no matter which cylinder was unplugged.. Thoughts?

Vids:




Im really lost on this one! The 3rd video you can hear the knock the best! Thanks in advance

[turbovanman²]

Sounds like valvetrain to me, check your cam, could be a slider and the cam is going flat.

[1984rampage]

Even after hearing the third video? It sounds more like a knock then

[Abkshelby]

That is definitely a knock not valve train noise. What weight motor oil is in this engine? It sounds like it is either a rod bearing noise of maybe a wrist pin. But I'd lean more toward a rod bearing. How many miles are on it or is the odometer broke like most did?

[black86glhs]

Definitely bottom end knock. Sounds a lot like the rod knock my S car had. Drop the pan, pull the rod caps and see what the bearings look like.

[1984rampage]

Just replaced the oil with 20W-50.. The odometer reads 76000 but its broke so its certainly more.. Is it possible for a novice mechanic like myself to fix the problem if it is indeed the rod bearings?

[Mario]

http://www.turbo-mopar.com/forums/vb...e&articleid=56

[turbovanman²]

I didn't hear any knock, Must be going deaf, eh, what was that sonny?

[blk86trbo]

Turbodave bought a Shadow with a "knock" that ended up being the power steering bracket rattling on something...

[turbo84voyager]

I know this may sound strange but when I bought my 89 caravan it sounded like it had a bearng knock. When I changed the oil I didnt fill the filter like I normially do and I figured when I start it if it had a bad bearing it would knock loud until it fills the filter. It was qiuet. I drove it like this for a while but noticed it was lacking power a little so I took a look at the cat. It was partially clogged. I removed the cat to try it and the knock was gone. I am not sure what it was, too much back pressure???

[turbo84voyager]

Turbodave bought a Shadow with a "knock" that ended up being the power steering bracket rattling on something...

I had this happen to me once. I thought one of my engines developed some valvetrain noise. Turned out one of the bolts holding this bracket worked its way loose.

[Vigo]

I didn't hear any knock, Must be going deaf, eh, what was that sonny?

and you have the pistons to prove it


sometimes the insides of cats crack into pieces and rattle when exhaust is blowing through them.

But i think this is motor noise. my .02