2f Engine knock help (Video attached) (1 Viewer)

[Rockiemosley]

You might check the little idler pulley that rides on the AC belt, bottom side of the AC compressor. Mine was making a heck of a racket because the bearing was bad and it was riding against the belt all the time. I believe there should be a small gap between the belt and the idler, so it might only engage for a moment when you turn the AC on. I was able to find a new bearing for this idler at a local bearing supply house.

 

[John Staton]

just throwing this out there....I had a terrible knock like that and thought the worst and it ended up being my smog pump. I had plans to demsmog anyway...just made me bump it up to the top of the list.

 

[Seth S]

I have a sound like that at idle that I am pretty sure is a pulley or powersteering pump going bad.

 

[Spike Strip]

With the engine warm and running, remove the spark plug wire to plug one at a time then replace and move to the next. If the knock goes away or substantially diminishes when you remove a plug wire, you've found your offending cylinder in the block. If the knock doesn't go away after sequentially removing the wires, your knock is either in the valve train or elsewhere.

 

[Natev22]

With the engine warm and running, remove the spark plug wire to plug one at a time then replace and move to the next. If the knock goes away or substantially diminishes when you remove a plug wire, you've found your offending cylinder in the block. If the knock doesn't go away after sequentially removing the wires, your knock is either in the valve train or elsewhere.

I actually did that last night, and it did not change the knock. Could the oil pump cause that kind of noise? That would explain why it goes away when I accelerate the engine, which causes an increase in oil pressure

 

[Spike Strip]

Take off the Valve cover and use the stethoscope to pinpoint if it's in the top end.

Valve adj is in order, too.

 

[Natev22]

I finally got around to adjusting the valves today.

Was the first time I've done this, but I think I did an okay job.

So far I have done new plugs, timing, and valve adjustment. Still no change to the knock / rattle sound. I did discover that the sound is loudest when I scoped the flywheel inspection cover.

Some professional opinions on how my valve train looks and sounds after the adjustment would be appreciated.



Any more thoughts are welcome.

Thanks again everyone

 

[JDS]

I finally got around to adjusting the valves today.

Was the first time I've done this, but I think I did an okay job.

So far I have done new plugs, timing, and valve adjustment. Still no change to the knock / rattle sound. I did discover that the sound is loudest when I scoped the flywheel inspection cover.

Some professional opinions on how my valve train looks and sounds after the adjustment would be appreciated.



Any more thoughts are welcome.

Thanks again everyone

Did you ever find the source? I have the same knock. Scoping the engine and block sounds perfect. Cannot pinpoint the source. Did your valve adjustment help? I realize this post is almost a year old. I have some winter garage time now to dig in on my noise.
All that listen to my 81 2F with 135k say probably push rod.
JDS

 

[Seth S]

I pulled my valve cover and ran the engine to watch the valve train and it was all quiet there. I still need to slack all my belts and run it again to see if any different (that will rule out accessories and the harmonic balancer). I'm still not sure what my root cause is but I'm being careful and not driving it now in case I have a bad bearing in the bottom end...I can minimize damage and ease a bottom end rebuild if it comes to that. I'll use it as an excuse to do the 2fe.

 

[JDS]

I pulled my valve cover and ran the engine to watch the valve train and it was all quiet there. I still need to slack all my belts and run it again to see if any different (that will rule out accessories and the harmonic balancer). I'm still not sure what my route cause is but I'm being careful and not driving it now in case I have a bad bearing in the bottom end...I can minimize damage and ease a bottom end rebuild if it comes to that. I'll use it as an excuse to do the 2fe.

Thank you! We are in the exact same boat. Please let me know what you find. Unfortunately, Rebuilds do happen!
JDS

 

[DJScotchTape]

Thank you! We are in the exact same boat. Please let me know what you find. Unfortunately, Rebuilds do happen!
JDS

I'm having this exact same noise, but it sounds like it's coming from my PS pump. It almost sounds like the fan hitting the sheath, but that's not it. The noise stops if I move my steering wheel to the left or right, and the knocking seems like it's right there in the pump.

 

[Seth S]

I'm having this exact same noise, but it sounds like it's coming from my PS pump. It almost sounds like the fan hitting the sheath, but that's not it. The noise stops if I move my steering wheel to the left or right, and the knocking seems like it's right there in the pump.

take the tension off the belt for the pump and spin it by hand. See if you can feel anything. Then try running the truck with the belt off and see if the sound goes away or not. with the belt off your alternator wont be turning but you can run the truck for a couple minutes if needed and no problem

 

[Seth S]

this is what mine currently sounds like:

 

[DJScotchTape]

this is what mine currently sounds like:

I'll give it a shot and update with what I find out. Mine sounds just like that, but with an incessant knocking!

Thanks for the advice.

 

[Seth S]

I still have to pull my plug leads one by one as well.

 

[OSS]

this is what mine currently sounds like:

That sounds horrible and bad. Try not to run it until it's fixed

 

[Seth S]

That sounds horrible and bad. Try not to run it until it's fixed

Yeah that’s pretty much the tactic I’ve taken. Other than short runs for diagnostics.

 

[aviafx]

Hey @Natev22, any updates on your truck?
I’ve been chasing a similar knock and will pull the pan soon.

 

[NeverGiveUpYota]

this is what mine currently sounds like:

Dang! I side w/ @OSS that sounds severe. Don’t drive till you get it figured out.

 

[NeverGiveUpYota]

Hey @Natev22, any updates on your truck?
I’ve been chasing a similar knock and will pull the pan soon.

Try the diagnostic test @Spike Strip added earlier.