Suspicious

Alright, I'm finally getting some time to work on the car again...
I'm rather sure that it's somwhere at the top, it doesn't sound "deep/clunky" enough to be a low end bearing..then again, this is my first non-german v8 and first non european car in general, so I really have no experience with those engines...
I pulled the spark plug wires one after another and it didn't have any influence on the noise, this sometimes helps me to identify a faulty low end bearing...
The engine also idles rather rough and seems to be a little rich, the exhaust sometimes sounds like one cylinder goes missing from time to time or like there's a racing cam in there, so a valvetrain related problem could be in fact the cause...

My ear tells me it's intake valve at cyl.4...it's rather easy to locate with the engine running without valve covers, but once I get under the car, it seems like it's louder down there and inside it sounds like it directly comes from the flexplate/torque converter area, all in all it's really weird.
I'll drain the oil next weekend and see if there's metal flakes in there. Also going to get the spark plugs out and see if they are all evenly colored... (I bet most of them are old, nasty and all black).

kevinkpk

My best advice at this point is a complete tune up, and oil change. Start from there.

Suspicious

Alright, time for a little Update:

I drained the oil, it looked rather good and didn't have any metal in it; I put a magnet through the drained oil to be sure, it came out clean.
I'll also cut the filter open to check that, too.

I also replaced the spark plugs and took a closer look at the distributor - That thing is toast, new one already ordered.
I am currently waiting for the new oil filter and distributor....

One thing I noticed: I can spin the last three pushrods by hand on the "knocking side", all the other can't be turned by hand...what is the normal condition for those?

I am also wondering if I should run thicker oil and maybe some additive. A friend of mine recommended to put some "liqui Moly engine flush" in it, run it for ten minutes then change the oil again. Put in some part-synthetic 15W40 and "Liqui Moly Hydraulic Lifter Additive" and see if the noise quiets down.

What is your opinion on this?
I am personally not a huge fan of those things, as this stuff mostly squeezes out some extra weeks at best and after that the trouble continues....I am close to pulling the engine and try a complete rebuilt...

kevinkpk

My response is in red in the body of your post I quoted, and did trim.

kevinkpk

In other words the valve in closed position, and that valve push rod just tight against the rocker arm. Tight meaning you can rock it back and forth with your hand, not tight against the push rod

Suspicious

Hi,
Thanks, I only new about the method with the engine running, I'll try your method as soon as possible.
When adjusting lash with the motor running, would be the "clicking" that starts when first loosening the rockers be the exact sound of tired lifters/ bad adjustment?
If so, could I try adjusting one with the engine running, and if the sound that occurs upon loosening the rocker is different than the noise I am chasing, would that mean the source of my noise is something else?

I also ordered a Oil pressure gauge (the car only has a light by factory); Hope that will tell me everything is alright...I really don't want it to be a rod knock....
One other thing I noticed: There was a lot of old oil sludge under the driver's side valve cover, actually way more than on the passenger side where the noise seems to come from... I am still thinking about putting some engine cleaner in it together with the fresh oil and change it again just after the few minutes...If it's that nasty under the valve covers, I can imagine what the lifters look like, best case would be freeing up a stuck lifter, worse case would be making things worse due to flushing all that rancid stuff through the whole engine...if it stays like that or gets worse, I'll have to take the engine apart either way, so I basically can't loose much.

I also found some more Videos:

https://streamable.com/ahx9i



https://streamable.com/rco73

Again, they're very short.

By the way, Thank you very much for guiding me through this and responding so fast, really appreciate it

Suspicious

Ok, finally, after months of on-and off searching, I believe I found the source of that noise...
I got the oil pressure gauge hooked up and luckily it read about 15 at idle and flew right up to 45-48 when rpms/load was increased.
After adjusting the rockers all correctly, flushing that sludged up engine with some marvel mystery oil (I'm usually not a big fan of those oils, put the pre owner obviously didn't take maintanance that serious, so I figured I'll give it a lillte clean-out) disasambeling and cleaning the carb, putting in a new distributor and wires and of course set the timing spot on and tune up the carb, that engine runs super smooth.
However, the knock persisted. I decided to take another real close look at the TC/flexplate and here's what I found:




It might be hard to see on that picture, but the flexplate has a nice little crack. I put a srewdriver in between the flexplate and the torque converter and carefully gave it a little wobble; I could clearly see the crack changing it's clearance, so there's no doubt that the flexplate is broken...
Well, looks like it's trans-remove-time now

I REALLY hope that a new flexplate willl finally eliminate that noise....

Thanks