Loud Clanking and rough idle

[KelseyM]

Hello all,

I was driving home last night and all of a sudden this noise started coming from the engine when under load. I recorded a you tube video to share the sound.

http://www.youtube.com/watch?v=8pQ-3GjK-Mo

Now the truck runs very rough at idle, maybe a timing issue?? Not sure so I posted for your guys help

[Terrys]

Hmmmm. Doesn't sound good. Not sure I'd run it it till I had a real good look-see.

[CdnSeries2a]

Sounds nasty, maybe a lifter?

[Bostonian1976]

Rod bearing?

[KelseyM]

Im not going to drive the truck until I find out whats wrong, I pulled the valve cover off and everything seemed to be in order... but I am not sure how to start diagnosing the issue

[JimCT]

motor mounts

almost sounds like the fan hitting something, I would check for bad motor mounts, could be shifting and hitting the shroud under load

[Cutter]

Sound frighteningly similar to my engine when the main bearings disintegrated. Hopefully it isn't.

[LaneRover]

Any chance you did an alternator conversion? My alternator bolt holes went a bit 'oblong' and as a result the alternator fan would rub on some metal once I got to a certain number of revs.

[KelseyM]

No, I still have the generator installed. I just started the truck again and it wouldnt stay running on its own, its seems pretty clear the timing is off.

[KelseyM]

just shot a video with the valve cover off, you guys see anything abnormal?

http://www.youtube.com/watch?v=WrB6RPFFOfI

[KelseyM]

Whoops! Coil wire came off, here is it running

http://www.youtube.com/watch?v=yAi4jpwCKYg

[LaneRover]

I didn't hear the knocking in the last video.

Does it only happen under load?

[KelseyM]

Yes, from a cold start it doesn't really make the noise but after running for about a minute it makes the noise in the first video I posted.

[LaneRover]

In the video it sounded like 'dieseling' to me. If that only happens under load then check to make sure the weights in your distributor aren't frozen.

If it happens all the time when it is warmed up, I'd look for something that has shifted or loose that somehow rubs on something else once warmed up.

[scatterling]

This sounds very similar to the problem I posted about a few weeks ago. Still don't know what it is. Does your sound only occur when your foot is on the gas? If you coast at any speed does it make the knocking? Mine sounds like it was coming from the bell housing but nothing is touching or rubbing in the clutch/starter motor area. Does it make the sound if you are driving and put your foot on the clutch and then rev the engine? Will it make the sound if you are parked and in neutral and rev the engine?
...sorry for all the questions