Knocking drivetrain noise

[Raceaprilia]

What can be wrong? It is very loud under load, no matter of speed. Even when backing up. Hope video will help. Idling it is all normal but when reving it up in neutral it start getting the knocking noise. Thanks for your suggestions. Truck has stock 283 with T5 behind it.

https://youtu.be/gkDyzYOmZ1Y

https://www.youtube.com/watch?v=gkDy...ature=youtu.be

[Raceaprilia]

Another video of engine run. knocking in higher rpm.

https://youtu.be/vV_mvqOkWX4

[pimpston65]

Originally Posted by Raceaprilia

Another video of engine run. knocking in higher rpm.

https://youtu.be/vV_mvqOkWX4

sounds like a bearings has spun. its kinda hard to be sure without hear it first hand. the way i check is give it gas while in gear and foot on the brake, if its a knock it will sound bad under a load, another way is to pull one plug wire at a time while its running to see if there is a change in the sound to find which rod is bad...

[pimpston65]

or it could be the lifters needing to be adjusted...

[68gmsee]

It sounds like a rod knocking or piston slap. Might be able to isolate to a side if it's piston slap with a section of garden hose to use as a stethoscope.

[Marshy]

That does not sound good. You can hear it at idle and all RPMs if you listen closely.

[cadillac_al]

I think it's the T5 since you can't hear it from under the hood but loud as heck in the cab. My gf has a 84 Z28 and the T5 has a petty bad knock but not as loud as yours. I think hers does in it neutral too, never goes away. I 'll bet if you try a stethoscope the noise will be from the trans.

[68gmsee]

Originally Posted by cadillac_al

I think it's the T5 since you can't hear it from under the hood but loud as heck in the cab. ..

After listening to all the videos, I think you may have something there. The one inside the cab seems to show the speedometer jumping in rhythm with the noise.

[hzgray]

I had flywheel bolts that came loose on my 292 that caused a knocking noise.

[storm9c1]

In the first video, the RPMs don't match up with engine speed cruising down the road. The knock there seems to be transmission related. But the second video, when you rev it, that seems to be matching engine RPMs. Listen carefully to the bellhousing area next and make sure this sound is coming from the engine. I agree with other comments about flywheel bolts.

It also wouldn't hurt to pop off the belts to eliminate an accessory (albeit doesn't sound like one). If you are going to pull the engine anyways, just pull back the trans, flywheel, and all, then run it one last time before you yank the engine. If you are lucky, the noise will be gone. If you are not, then continue pulling the engine and investigate the bearings.

['63GENIII]

The two above sound like they might be right. A clutch cover bolt bolt backed out making contact on every revolution maybe? Can you pull an inspection plate to look at the bolts on the clutch cover? Doesn't sound like lower end. Too slow.

[homemade87]

You guys may think I am crazy but I think I hear a sound coming from the carb that I recognize as a dead cylinder with a open valve . It is something I have heard many times . I thing the popping sound may be coming from the intake fuel being ignited from a stuck or lazy or even a broke valve spring . I have had and seen some weird things happen like this . I only heard the popping under load while driving .

Shot in the dark but try pulling one plug wire at a time and see if the popping stops . Once you take the fire away from that cylinder the popping should stop if this is the case .

Just something to consider . Of course this is bases of of internet sound from youtube .

[Raceaprilia]

Thanks for the suggestions. I pulled intake over the weekend and figured that cam and lifters are worn out badly. Could be age or syntetic oil that I put in when assembling truck. Cylinder #1 header look clean color when all other 8 are nicely burned blue on SS header pipes. I will look into flywheel as well just to be sure all is good there. Couple valves do not even open - or open barely when rotating engine.
Decided to swap to 5.7 but not much to choose from here in Europe. Looking at new goodwrench 350/260hp longblock engine for 3000$. Not sure if price is high or reasonable but as I said not much to choose from. If I go this route - do you guys think it is ok engine for the money?
Or if anyone of you guys in USA can ship LS based 4.8, 5.3 or 5.7 to Europe to do the swap? on USA ebay I didn't notice anyone shipping worldwide

link to the german goodwrench engine:
http://www.ebay.de/itm/5-7l-350-V8-M...QAAOSw~OVWxzhx

[toolboxchev]

You have something serious amiss. Do not drive that rig!

[Marv D]

Sorry to hear about the demise. It's not uncommon. Cam failure loads the bearings with debris, takes out the crank, scores cylinder walls and makes a mess. Looking for a step up is a wise move IMO. And your thought of the LS based motor is a good one. Our beloved SBC has it's days numbered. Out of production in domestic cars the cores are now 15+ years old. And the aftermarket sees the handwrighting on the wall. There is already MANY parts that used to be as common as dirt, and about as cheap,,, that are now EXTREMELY hard to find at any price.

So.... As for the LS, It would probably be about the same $ to have a complete vehicle shipped I would think. Then you would have the computer, all of the sensors, trans cooling fans, fuel tank / pump,, a LOT of crap that doesn't get budgeted in a LS swap. Try looking for a wrecked <2000 (for the drive by linkage and not drive by wire) and see what kind of deals there are out there with international shipping.