10W40 Weight Causing A Lot Of Tapping.

[Thomas525]

https://www.youtube.com/watch?v=tNQ13V9HJkw

Run that video and your cold video at 50% speed (you can adjust this on youtube's settings for that video) and you will notice an underlying secondary noise on your engine.

This is an important issue to isolate and get to the bottom of. Remove all the belts and run the engine when cold, ideally when the environment is more quiet. You will have about 4 minutes before the engine begins to overheat so its enough time for you to isolate the sounds, throttle up and down using the throttle cable, etc. In fact remove the rad cap, will give you a little more time. Top up to full with water before you close up later.

You have a bad problem actually, but from all that I've heard there's a fair chance the engine will soldier on all the way without falling apart. Don't run boost or race this engine, but you don't need to baby it either.

[fo3]

Yeah, probably piston slap. Pretty common in these motors as nearly every euro rebuild vid shows old pistons with side wear. If you hear that noise expect a rebore in the future but I wouldn't be worried until it starts using or burning oil.

I would like to go LS! LOL At the very least, find another M50 and freshen it up.

I added STP additive, changed the filter, started up the car, revved to 2k for a minute and no more ticking/tapping. I let it run at idle for 15 minutes and no ticking. I haven't driven the car yet but, I will in a bit and see if there is a change.

I think you asked about oil over a year ago and back then I said I have a similar problem and said use 20w-50 when you can. I have no idea how cold it gets where you are, but if temps are above 5 celcius just use castrol gtx 20w50 - find it on sale and stock up. You have an old motor that's no doubt already worn so there's no point worrying about a thin base oil to prevent future start up wear, unless in the winter months when the ambient is freezing.

I use whatever is cheap because I'm expecting a motor rebuild soon. Sometimes that's a 10w-40 or a 15w40 on sale but my engine is always louder when I use a 15w40, (a good 20w50 is getting really hard to find!).
I never need a lower base oil visc spec because winters here are 15C - I've tried a liquimoly 'lifter' additive with the thinner oils that was supposed to be good and help clean them out but it didn't help much, so I'm just going to stay with a high quality+additive pack 20w50 oil.

[ross1]

Oil is thick when cold, thin when hot. You can do the rest of the math on that I'm sure.



So there's your problem. Maybe you're wondering why its ticking when hot when both oils are supposed to be 40 weight when hot. Simple. They fucked up the grades slightly in the bottles that you're using.

So you solve your problem in the following simple ways. Go get sae 50 oil. Straight 50. Pour in 4-5 litres. Run the engine 10 minutes at idle to mix it up nice and good. You'll get a blend that's thicker when hot - should fix your problem. Drain out half of it and set it aside for your next oil change. Leave the rest of it in there, ensure there is enough oil. Finish.

All engine oil is a blend.

Or add 3 litres sae 50 oil. Not multigrade oil. That will fix your problem immediately. At the usual oil change interval, don't change the oil, just change the filter. Then wait another 50% of the usual oil change interval and then change the oil and filter together. Switch to 20w50 oil. At your mileage you should be doing that. Ask Shaffer, he will tell you that BMW recommends that for higher mileage M50s.

IF these solutions don't solve your problem, then its time for you to change the lifters.

I see you have once again seized upon a gullible audience(sorry Drew) to pontificate your gibberish to. Aren't you needed at the E36 forum?

[R Shaffner]

When I thought back on this it reminded me of old Kung Fu movies where the Zen master says "The path to enlightenment is rarely straight. It has many twists and turns." (Or something like that.)

Drew, I understand about the rod knock you heard. I don't disagree -- when it's bad nothing will hide it. But when bearings are worn, the classic symptoms are more noises and low oil pressure. It's reasonable to suspect that's what you have with a high mileage car.

In other words, of course the bearings are worn. Some bearing are probably worn more than others. And in that case, thicker oil usually helps. (My brother has the same car. He used 10W30 religiously until it got over 200,000. Since then I've been telling him to use 15W-40 or 20W-50. It slows down the leaks and burning, helps the compression, runs quieter, and helps maintain oil pressure throughout the system. His engine now has 280,000 miles, still without a major repair.)

I (and some others) just focused too much on the lifter issue instead of the generally worn old engine issue.

And I personally wouldn't rule out the different/wrong filter as a contributing factor, because you said the change was sudden and 10W-40 is the same thickness as 15W-40 at 100C. So the oil isn't thinner at operating temp, and is barely thinner below that. In any event, you'll get to figure it all out over time.

About STP -- since I suggested it I wanted to follow through. I knew people who used it with every oil change many years ago, so I don't think it would cause long term damage so long as the end result, meaning the overall oil viscosity, is good for that engine.

But I don't think STP is multi-viscosity -- I think it's more like a real heavy single weight oil. And I don't know whether it has any detergents that old engines need. So my personal recommendation would be to change it to a high mileage 20W-50 oil pretty soon. I'd also try the same in synthetic every now and then (different oil and detergents) to help clean things out. And frequent changes, of course.

That's all I got. Good luck!

[Thomas525]

I see you have once again seized upon a gullible audience(sorry Drew) to pontificate your gibberish to. Aren't you needed at the E36 forum?

Hmm. Lets see. Someone essentially follows my advice in substance, and it works for him, and you don't understand that. Maybe you think that pouring molasses like that stp treatment in there is a good idea. Worked well in the old carby days I suppose.

[drewusmaximus]

[QUOTE=ross1;30241613]I see you have once again seized upon a gullible audience(sorry Drew) to pontificate your gibberish to. Aren't you needed at the E36 forum?[/

Gibberish? pontificate? Once again? E36 forum? Please elaborate. It's never wise to accuse without the proper backing.. It adds strain to one's self awareness...

[ross1]

[QUOTE=drewusmaximus;30242021][QUOTE=ross1;30241613]I see you have once again seized upon a gullible audience(sorry Drew) to pontificate your gibberish to. Aren't you needed at the E36 forum?[/

Gibberish? pontificate? Once again? E36 forum? Please elaborate. It's never wise to accuse without the proper backing.. It adds strain to one's self awareness...[/QUOTE]
What?

[drewusmaximus]

[QUOTE=ross1;30242088][QUOTE=drewusmaximus;30242021]

I see you have once again seized upon a gullible audience(sorry Drew) to pontificate your gibberish to. Aren't you needed at the E36 forum?[/

Gibberish? pontificate? Once again? E36 forum? Please elaborate. It's never wise to accuse without the proper backing.. It adds strain to one's self awareness...[/QUOTE]
What?

It is safe to conclude you can't. Thank you all for your insight and advice. Everything done to my car, I've done myself with the little knowledge I know about the E34, hence utilizing the forum. Although luck is never on my side, I will continue to do what I can to make the car what it once was, with no fancy tools, or garage. Since we all live in a binary system, the judgmental will always be around, because without them humbleness cannot exist. Needless to say, those who lack self-awareness have forgotten where they once were.

Thomas525.., I will pull the belt and test at low idle for a few minutes and adjust the oil accordingly this weekend. Thanks for the advice!

[drewusmaximus]

When I thought back on this it reminded me of old Kung Fu movies where the Zen master says "The path to enlightenment is rarely straight. It has many twists and turns." (Or something like that.)

Drew, I understand about the rod knock you heard. I don't disagree -- when it's bad nothing will hide it. But when bearings are worn, the classic symptoms are more noises and low oil pressure. It's reasonable to suspect that's what you have with a high mileage car.

In other words, of course the bearings are worn. Some bearing are probably worn more than others. And in that case, thicker oil usually helps. (My brother has the same car. He used 10W30 religiously until it got over 200,000. Since then I've been telling him to use 15W-40 or 20W-50. It slows down the leaks and burning, helps the compression, runs quieter, and helps maintain oil pressure throughout the system. His engine now has 280,000 miles, still without a major repair.)

I (and some others) just focused too much on the lifter issue instead of the generally worn old engine issue.

And I personally wouldn't rule out the different/wrong filter as a contributing factor, because you said the change was sudden and 10W-40 is the same thickness as 15W-40 at 100C. So the oil isn't thinner at operating temp, and is barely thinner below that. In any event, you'll get to figure it all out over time.

About STP -- since I suggested it I wanted to follow through. I knew people who used it with every oil change many years ago, so I don't think it would cause long term damage so long as the end result, meaning the overall oil viscosity, is good for that engine.

But I don't think STP is multi-viscosity -- I think it's more like a real heavy single weight oil. And I don't know whether it has any detergents that old engines need. So my personal recommendation would be to change it to a high mileage 20W-50 oil pretty soon. I'd also try the same in synthetic every now and then (different oil and detergents) to help clean things out. And frequent changes, of course.

That's all I got. Good luck!

I understand now. My wife's friend's car was probably at the worse stage, whereas mine could be at the beginning stage and the sound might be minimal to where I can't really notice it. I will try Thomas525's advice by pulling the belt and let it run at low idle. That will help with determining the sounds. In the meantime, I will switch the oil so at the very least, it will help with protection.
Thanks for your input!

[Thomas525]

Drew,

Firstly ignore Shaffer's advise. He overthinks due to a lack of experience, and comes to the wrong conclusions.

Second, don't add and change the oil as I suggested. Since you've already dumped in the stp mollasses and it works to your satisfaction, leave it alone.

Third, you have new oil in there. It is not impaired by the stp. So all of its "detergent " properties are still fine. Some people seem to think that the detergent properties of engine oils should be like the detergent properties of laundry soaps - produces whiter than white cams. No. The whole idea of detergents - this has been increasingly understood to be a marketing gimmick. Hardened carbonised dirt in the engine can only be scrapped off manually. Solvent engines flushes have sporadic success with hardened dirt . Softer carbonised sludge will be dissolved out with repeated exposure to clean oil alone - most sludge is gone within 3 oil changes. They dissolve out even faster with solvent engine flushes. That's all there is to dirt and detergents on the engine.

The best way to protect your engine is to use fully synthetic oil of the correct ratings, and change it on time. Fully synthetic oils burn at higher temperatures than dino oil and are thus less likely to form carbonised dirt, that's all. It is NEVER going to get more complicated than that.

Fourth, leave your current oil filter alone. It is obviously compatible with the E34. But in future please use the mahle ones. Just get a whole bunch and keep one in the car at all times.

Fifth, remember to remove the rad cap when you take out the belts. And have a watch in your hand, or a countdown timer, and at the 4 minute mark go into the cabin and check the temp. If it has not passed the 12 o clock mark, continue your investigations but check every 40 seconds. Ideally, have someone sitting in the car to alert you to this. And don't bother to take any videos etc. This is purely for you to use your ears alone.

Sixth, if you have a long rubber hose, like a fuel hose or something, you can put it through the slats of the intake manifold onto the engine roughly where each piston is in turn, and your ear at the other end. You might hear some sound variations. Practice doing this on a hot engine first until you get the hang of it.

Seventh, you will be leaning over the engine alot. Make sure your long hair and chains are out of the way. Make sure your footwear has good grip and your feet are firmly planted and will not slip - test this first. And put a gloved hand on the opposite side and lean against it. This way you will not slip and hurt yourself.

Eight, remove the fuel rail's and valve cover's plastic covers. It may help make the noise clearer.

Ninth, listen to the sound from the exhaust manifold side as well, but of course the main spot for you is going to be infront of the throttle body.

Tenth, before all of this, listen to your own hot and cold videos on youtube with the speed at 50%. Get familiar with the secondary sound I was talking about. Then goto your engine.

Eleventh, after all the belts have been removed (don't bother to reinstall the cluth fan just yet), spin all the pulleys by hand and see if you can get any odd sounds. If you do, video that and post it here. Also stick the rubber hose on it and spin as well to better identify the sound.

Twelfth, IF in the unlikely event that the bad sound totally disappears after both belts are removed, then a. Stop the engine. b. Sing ave maria c. Install the ac belt first and run the engine and see if the sound reappears, if it doesn't, install the alternator belt and see if it appears.

[R Shaffner]

Drew,

I believe Ross1 was speaking to Thomas525 with the gibberish comment, not you. He was trying to tell Thomas to stop bothering you.

You'll get some odd opinions and suggestions on this forum. Some people know a whole lot. And many think they do, whether they do or not. Fortunately you can decide whom to listen to and whom to ignore. And you can find other threads that address almost every issue and questions you might have.

[drewusmaximus]

I see you have once again seized upon a gullible audience(sorry Drew) to pontificate your gibberish to. Aren't you needed at the E36 forum?

My sincere apologies. For some reason I didn't see this portion of the thread at all. What I saw was what I posted below. Odd that I didn't see this part.

[ross1]

My sincere apologies. For some reason I didn't see this portion of the thread at all. What I saw was what I posted below. Odd that I didn't see this part.

No apology needed, sir.
It's been clear you've had some struggles with this car and that is the sort of customer thomas525 prefers to "coach". He's been banned perhaps half a dozen times here and only God knows how often elsewhere. If I put my mind to it I could come up with close to ten user names. It always boils down to his preaching methods and procedures that range from dubious yet harmless(50 weight oil in your crankcase for example) to outright absurd and dangerous (running your engine at 6000 rpm for 15 minutes).
When confronted he gets disruptive and then the hammer falls, again. This last visit it seemed for a little while that perhaps they finally got his meds right but no.

[ross1]

Drewusmaximus: Please excuse this diversion on your thread. And please forgive and forget my comments about moisture. It shows up in the crankcase every time we start a cold engine, but let's not bother with that and the lifter discussion.

Ross1: I respect and agree with many of your helpful posts here, but I can't agree with most of this last one. Perhaps what I read isn't exactly what you meant.

For example, you said the thinner oil might not be heavy enough to handle the compression load... Surely you don't mean that. Generally, oil isn't compressible. Jack oil is usually 10W, and 0W-30 oil works in many lifters just fine. So both thin and heavy oils will handle the compression forces.

And you said that oil with a higher bottom number works better than others when the engine is hot. I gather that must be your experience, which again I respect, but that's hard to explain. The first number shows the viscosity at freezing, the second shows it a boiling. The oil engineers are telling us that 0W-40 and 15W-40 have the same viscosity at 100C (the same as 40 weight oil), which is the temp of these engines when hot.

My experience is different. The spec oil for my '97 540i was what you like: 15W-40 Rotella. That's all the car ever got until I changed the chain guides at about 200,000 miles. After sitting with the oil drained for most of a week, most of the lifters made noise when I started it back up. All but one got quiet within a minute. But one lifter just kept ticking. I revved the engine as BMW recommends, drove it hard and easy. Even added some cleanser at the next oil change. No luck. So I tried a round of 10W-30 synthetic oil -- a little thinner, different detergents, and synthetic. The lifter got quiet before the next oil change, when I went back to 15W-40 Rotella.

In short, I agree that thicker oil can help make many internal parts of the engine quieter. But when it comes to forcing oil back into an old lifter, my personal experience (and logic) is that thinner oil will flow into that tight/partially clogged space easier.

That's all from me on this topic.

Just to clarify a bit and return to the topic of Drew's noisy engine.
When I say the oil is too thin what I'm meaning and perhaps didn't express well is that is too thin given the clearances in a worn lifter. Lifter gets the squeeze and the oil gets past the piston, a heavier oil which flows slower resists this better.
I understand exactly what you correctly stated about the lower W(winter) # and the top #. I do not pretend to be a lubrication engineer, my statement is based solely on my own experiences. For whatever reason, unknown to me, oils with a lower bottom # seem to also fare better when warm. Again, my experience, ~40 years worth.
The thing that a lot of folks seem to discount when changing oil is that you are now using fresh oil, regardless of weight. I suspect your experience with that single lifter quieting itself is more a function of the additive package at work than the viscosity of the oil used.

@ drew I heard nothing in that clip that sounds like bottom end noise but it is very hard to judge from these clips. I strongly advise you not to be running that engine with the water pump disabled as has been suggested. Accessory noise don't resemble bottom end noises so it's another futile exercise suggested by that fool. In several previous incarnations he'd have been having your topping of the crankcase with diesel fuel.
A noise that DOES often resemble bottom end noises is a loose spark plug. Typically, it can be felt by simply holding your hand on the ign coil of the suspected cylinder.
From some of your other posts I gather your car has not led an easy life. A succession of short interval oil changes just may free up those sticky lifters over time. Other times they are just shot and you'll need to live with it or spend for the repair.

[drewusmaximus]

Just to clarify a bit and return to the topic of Drew's noisy engine.
When I say the oil is too thin what I'm meaning and perhaps didn't express well is that is too thin given the clearances in a worn lifter. Lifter gets the squeeze and the oil gets past the piston, a heavier oil which flows slower resists this better.
I understand exactly what you correctly stated about the lower W(winter) # and the top #. I do not pretend to be a lubrication engineer, my statement is based solely on my own experiences. For whatever reason, unknown to me, oils with a lower bottom # seem to also fare better when warm. Again, my experience, ~40 years worth.
The thing that a lot of folks seem to discount when changing oil is that you are now using fresh oil, regardless of weight. I suspect your experience with that single lifter quieting itself is more a function of the additive package at work than the viscosity of the oil used.

@ drew I heard nothing in that clip that sounds like bottom end noise but it is very hard to judge from these clips. I strongly advise you not to be running that engine with the water pump disabled as has been suggested. Accessory noise don't resemble bottom end noises so it's another futile exercise suggested by that fool. In several previous incarnations he'd have been having your topping of the crankcase with diesel fuel.
A noise that DOES often resemble bottom end noises is a loose spark plug. Typically, it can be felt by simply holding your hand on the ign coil of the suspected cylinder.
From some of your other posts I gather your car has not led an easy life. A succession of short interval oil changes just may free up those sticky lifters over time. Other times they are just shot and you'll need to live with it or spend for the repair.

Thanks for the clarification. I won't take the risk of pulling off the belts. I will check the coils, manifold bolts, and maybe injectors. I never suspected a failing bearing because I've been under the car to pinpoint the taping/knocking and I don't hear it at the bottom, unless it's at an early stage. I don't want a band-aid fix because, eventually the engine will fail, especially driving 60 miles a day. I wish I had the time to replace the lifters. My vacation isn't until 4th of July week and it's only going to get warmer from this point on. I will have to make-do until vacation but, in the meantime, I will inspect the mentioned areas. Thanks again. I misread your post and didn't see what you quoted on that post.

[drewusmaximus]

My plan for this weekend:

Change oil to 20W50.
Pull VC, inspect plugs, reseal half moons.
Install driver side brake shoes.
Retighten inner dogbone nuts.
replace water pump
replace coolant temp sensor
coolant flush while I'm working on the cooling system
Differential flush

I think that's good for now.

Thank you all for the support and patience..

[fo3]

The majority of your noise has gone away right? So why fix something that isn't broken? The STP has probably thickened up your 15w-40 so why change it?

Besides, your next oil change would be due when heading into your winter so you'll be best off with a 10w40 or a 15w40 later on in the year. I know what you used last brought on the noise but I'd try with a diesel oil like ross suggested before next winter. Diesel oils are commonly used in noisy old euro motors that need thicker grades as they have a lot more additives than petrol motor oil does so you might not get the same noise with a diesel 10w40.

So keep what you got for now, 6mths from now try 15w40 caltex delo or shell rotella mineral, or 10w40 rotella synth in winter and see how it goes. Then keep using it or switch to 20w-50 high additive petrol oil for summer 2020

[drewusmaximus]

The majority of your noise has gone away right? So why fix something that isn't broken? The STP has probably thickened up your 15w-40 so why change it?

Besides, your next oil change would be due when heading into your winter so you'll be best off with a 10w40 or a 15w40 later on in the year. I know what you used last brought on the noise but I'd try with a diesel oil like ross suggested before next winter. Diesel oils are commonly used in noisy old euro motors that need thicker grades as they have a lot more additives than petrol motor oil does so you might not get the same noise with a diesel 10w40.

So keep what you got for now, 6months from now try 15w40 caltex delo or shell rotella mineral, or 10w40 rotella synth in winter and see how it goes. Then keep using it or switch to 20w-50 high additive petrol oil for summer 2020

After driving to work and back home the next day, the sounds are back. it seems the additive doesn't help after I drove about 70 miles. If I rev the engine to 2500 - 3000, it goes away. when I stop at a light, it slowly comes back. When I start the car, it's quiet. After about 10 minutes of idling, the taps/ticks gradually surface one at a time. Then it's several. Then I can hear one tapping stop and another start, then stop/start, stop/start, etc, etc.

I think it's time to change the lifters. Worse case scenario, I might have to change the rod con bearings. I think I can do that from underneath but, there are two sizes according to realoem .50 and .75 and I don't know which one my engine takes. What do I have to lose by changing the bearings? Turn the crank to move a cylinder to TDC, remove the two bolts, remove lower bearing, push up piston just enough to remove old bearing, apply engine lube on the bearings, put cap back on, and tighten new bolts to 35 ft. pounds. At the very least, the engine will have new bearings and last a bit longer. Since I am planning to replace the oil pan gasket, might as well attempt the bearings. I think I have to get the connecting rod bolts since, they are one time use. This is new to me but, I will do what it takes to keep Grandpa running. It's a great car but, it's 24 years old.

Last 7 of my VIN for realoem = GB38765

Sorry. Those aren't the bearing sizes. These are:

04	Connecting rod bolt	L=44MM	X	09/1994		11241739728	$4.12		ENDED
04	Connecting rod bolt	L=44MM	X	09/1994		11241739729
05	Bearing shell, blue	45,00MM(0)	6			11241284850	$15.98
05	Bearing shell, blue	44,75MM(+0,25)	6			11241284852	$21.31
05	Bearing shell, blue	44,50MM(+0,50)	6			11241284854	$21.31
06	Bearing shell, red	45,00MM(0)	6			11241284849	$16.49
06	Bearing shell, red	44,75MM(+0,25)	6			11241284851	$13.27
06	Bearing shell, red	44,50MM(+0,50)	6			11241284853	$13.27

[fo3]

Yeah, you know you can't get the sump off without either lifting the engine out or suspending the engine from strut tower hangers and dropping the subframe out right?
You also know that you need to check the crank and get wear/clearances etc which is why there are different bearings available. It's not something you should do with the engine still in the car and working from underneath.
Also if the noise is piston slap then you may have not achieved anything doing crank bearings the hard way. Forget about that.

Do what is suggested, buy a second motor on the cheap and rebuild that properly. That way you can do timing chain, guides, checking the piston and ring wear, rod bearings, reboring and stroking in your own time.

[drewusmaximus]

Yeah, you know you can't get the sump off without either lifting the engine out or suspending the engine from strut tower hangers and dropping the subframe out right?
You also know that you need to check the crank and get wear/clearances etc which is why there are different bearings available. It's not something you should do with the engine still in the car and working from underneath.
Also if the noise is piston slap then you may have not achieved anything doing crank bearings the hard way. Forget about that.

Do what is suggested, buy a second motor on the cheap and rebuild that properly. That way you can do timing chain, guides, checking the piston and ring wear, rod bearings, reboring and stroking in your own time.

I guess you're right. Wishful thinking on my part. Oh well, I will work on my list and cross that bridge when I get there.

Thanks!

[bigsixe34]

Besides, your next oil change would be due when heading into your winter so you'll be best off with a 10w40 or a 15w40 later on in the year.

6 months? Heading into winter?
He said he drives 60 miles (95km) a day and this is conventional oil we’re takking about. At Dino/3k interval he’ll be due for a change by early June. Which is when we enter our hottest season up here...
I had good results from using 15w-50 in the warm months. 20 cold would be fine too.

[bigsixe34]

Also Drew, I admire your desire to restore your current motor but I really think you’re better off using all those goodies you have (lifters et al) on a second motor that you can build easily on a stand. Drop it in when you’re done and voila. Ready for a road trip.

[bluptgm3]

…I still believe you need to check oil pressure in hot state condition.

Keep in mind that there are several formulations of 10W40, Mobile 1 has two that I am aware of and I am currently using the High Mileage variation.


Sent from my iPhone using Tapatalk

[drewusmaximus]

…I still believe you need to check oil pressure in hot state condition.

Keep in mind that there are several formulations of 10W40, Mobile 1 has two that I am aware of and I am currently using the High Mileage variation.


Sent from my iPhone using Tapatalk

I'm trying to figure out how to perform an oil pressure test. I assume I need to tap into where the oil pressure sensor is, or the oil pressure sending unit is? I found a couple of videos but, it doesn't show where to connect a gauge and how to connect it.

[R Shaffner]

I suggest going to realoem.com. Click the link to seach Classic BMW models. Specify your car and look for the oil pressure sensor or sending unit on the diagram. Then the process would be to pull the sensor, take it to an auto parts store to match the treads with something that will go in the hole WITHOUT hurting the threads. Rent/buy a pressure gauge from the store and test the pressure, especially while the engine is at operating temp.

Now that you've replaced the questionable oil filter with the right one, and thickened the oil, you're moving away from oil as the problem, and instead you're looking at what the various noises are, how serious they are, and what you can/should do about them.

Ticking valve lifters can be annoying but they won't hurt anything (not themselves or anything else). They could be ticking because they are old and somewhat dirty inside. Or they could be ticking because the oil pressure is low. Personally I'd give fixing them them a lower priority while looking into the causes of more serious noises.

Remember the procedure you were going to do to check for worn bearings, with a dowel or screwdriver in the plug hole? I still think that's worth doing. And remember how one of the knocks seemed to go away or get quieter when you unplugged that coil pack? I'd start your test with that cylinder and then try others. Repeat the tests as needed until you'e confident you've noticed any play and keep track of the results.

Again, all bearings on a car that old will be worn somewhat. The question is how worn -- whether they are worn enough to knock and let oil escape from the pressurized oil passages so fast that other parts aren't getting enough oil under pressure. (If you find that you have play in one or more bearings, then the life of that engine is more limited unless it gets major repair. If you can't find any play, some might still be there of course, just hard to notice. But that would be encouraging and make me want to look at other causes for the sounds.)

The videos you posted of the sounds helped. I suggest posting some new ones too, preferable after those tests. Move the camera around to different parts of the engine so we (and you) and see if/how the sound changes as you do.

And of course, if any sounds are coming from a belt-driven component, that would be good news at this point.