W114 engine knocking

[kavadarci1]

Hi,

Little bit of background before I ask my questions:

The car had spark plugs, cables, oil replaced and came with upgraded crane igntion and original coil.
Valves were adjusted to 0.003 and 0.007.
The car starts fine, idles fine and has power.
Piston compression:
1. 100psi
5. 100psi
3. 120psi
6. 130psi
2. 120psi
4. 100psi

Oil pressure sits at 10 on idle and increases as the engine rpm increase, nothing unusual there.

The "only" problem I have is "noise" coming from the engine under load, specifically accelerating from 80 to 100km/h.
I called this noise knocking, pinging, flapping, metalic clicks at least multiple times so I don't know if I am describing the noise properly.
I think the best description that I found was a metal can full of marbles shaken violently. That's how it sounds.

One mechanic decided it is the crankshaft bearings causing the noise.
Another engine rebuilder suggested opening the engine as a last resort and suspects it is the timing.

NOW,
on the timing.
Since my three way vacuum valve needed for US emission doesn't work I am bypassing it.
My vacuum lines are as this:

Second carb (closer to the firewall) has the lower vacuum going to the dashpot.
For the first carb (which has excellent vacuum) I have tried three options:
1. plugged (this setup gives the best results with almost no pinging or at least less)
2. going to the advanced plug of the distributor it almost stalls and it pings
3. going to the retarted plug of the distributor, pining is very pronounced.

I have had my timing set to 3 btdc, 8 btdc and 13 btdc as some suggested and the best results I got are at 0 with the first carb plugged.

All of this leads me to the distributor or ignition setup.
i removed the distributor and found to be rusted inside.
cleaned and lubricated, all good

i also confirmed the timing of crane is as per their recommendation.

i have now sitting at 8btdc and the car has power, idles fine, starts fine.

i now have the pinging noise significantly reduced but i also noticed knocking when rpm engine goes down or on deceleration.
it comes pronounced just before the engine settles.

i have no idea what it is nor where to start to look.
Here is a video of my engine.

M130 working - YouTube

I appreciate any input.
Thank you.

[Pooka]

I don't think that sounds like crank bearings. They have a deeper tone, like a five pound sledge hitting a solid piece of metal.

It sounds like your cam is making the noise. Pull the valve cover and check the cam for grooves and check the cam followers for wear. I know you said you adjusted the valves, but if a cam lobe is grooved or a cam follower is dished out you will get this type of noise.

It could be that one of your cam followers is not seated correctly. If one of them looks askew this is likely your problem.

It is also possible for the adjustments of the valve position have worked loose. If an adjusters turns easily then that one needs to be replaced.

[kavadarci1]

Thank you
I have checked (visually) the camshaft and looks good to me
I even removed the oil pipe and cleaned to make sure oil gets properly to the top
Now cam followers, which one are cam followers?
Everything feels tight to me but I might not know how to check properly

Here is a pic of my camshaft with the valve cover removed

[Palolo]

The cam followers are the arm-shaped parts that come in to contact with the lobe and actuate the valves by "following the lobe". You will see one under each cam lobe, and you will also see a lock nut and adjuster screw on the end, which is what you use to set your valve lash...

(Some folks call them rocker arms generically, but since this is an overhead cam engine, the follower is actually in contact with the cam, vs the typical American pushrod engine where the rocker arms do just that, they merely "rock" to translate cam action via the lifters and pushrods, into valve action.)

Good luck with it!

[Palolo]

Originally Posted by kavadarci1

Everything feels tight to me but I might not know how to check properly.

You will need a metric feeler gauge set, and a way to rotate the engine safely, ie, so it doesn't start accidentally. You can remove the coil wire to be extra safe, and use a large socket on the front crank nut. Starter bump-switches typically aren't accurate enough to stop where you want them to, or at least that's been my experience.

There are better guides online, but in a nutshell, you rotate the engine until the valves are closed (TDC) for a particular cylinder, then you slip the feeler gauge in between the cam and follower pad. You may need to try a size up or down to determine what the gap is, then since you're there, you may as well adjust if needed.

You can do some of the other cylinders' intake and exhaust valves at the same time, or just rotate each cylinder through TDC and do both those valves at once.

BTW, when setting valves: too tight is just as bad as too loose. (This ain't spring break. )

Edit: I just watched the video. How many horsepower does the red valvecover add? LOL. sounds like you have knocking on overrun.

[kavadarci1]

Thank you
That's exactly what I did following the Haynes manual
Exhaust is 0.007 and intake is 0.003

By the way I forgot to mention the overrun knocking is not present in cold start
Only when the engine goes above 175

Cold has no knocking at all

My concern is with the 0.003 the feeler gauge is so thin and maybe I have those too tight
In my opinion all were the same tightness

Will too tight cause the noise? I always assumed loose is the reason for the valve noise

[kavadarci1]

Actually,

After reading more about valve adjusting I think mine are too tight.
The feeler gauge requires tons of effort to slide it through and everywhere says slight drag, mine is for sure more than slight drag.

Can too tight valves be the reason for my overrun ticking?

how tight should the gauge be when I'm adjusting?
The 0.003 gauge is really thin to begin with.
Thank you.

[Palolo]

You should feel some resistance as you pull the feeler out, and also be able to slide it back in (against some resistance) without feeling that you're going to bend/kink it.

If you think it will jam and kink, that's too tight.

If you don't feel it dragging on the metal, that's too loose.

Kinda hard to describe...LOL

[kavadarci1]

I understand now
I can picture it
What I did is not how it should have been done
No way to slide the .003 you have to force it
And yes it bends like crazy
I am probably .002 or even 001
I will redo the work and post the results

[Carpenterman]

I guess I'll chime in, but it's just speculation.

IMO, a miniscule difference in valve clearance would not cause the noise I heard on the video.

It appears to me that the noise is high in the engine. Since I don't think it is valve train noise, I would think that it could be a wrist pin, that goes from being in compression to tension as the engine goes into "braking" mode as the rpms decrease faster than the ignition/fuel determines. Think braking horsepower, if you know what I mean. The reason you don't hear it when the engine is cold is because the piston/bushing hasn't expanded enough to cause the excess clearance; hence the knock appearing when it heats up.

Or does the clearance get tighter as it heats up? What does everyone say?

Just a guess. At any rate, if it was me, I wouldn't worry about it until it got much worse.

[kavadarci1]

The ticking is not present on cold start only when it goes above 175
I will adjust the valves properly just do doesn't cause excessive wear

I have tried to unplug the spark plug wires one by one to see if that makes any difference and it didn't

The noise does seem to be coming from the upper engine area and to me feels like it is on the carbs side.

On Wednesday I will adjust the valves and report back


Is there anything I can do to confirm it is wrist pin, thicker oil, Lucas products different gas etc

[Palolo]

Have you checked for timing chain wear?

Is the tensioner verified to be good?

If the chain or tensioner is dodgy, the cam and crank can change their relationship--if that change is large, there might be piston/valve interference. Note that when the engine is accelerating, the crank is pulling the cam (tension on the left side of its chain/gear) vs when letting off the gas and on overrun. Normally a tight and fresh chain would minimize the effects on overrun.

Might be worth looking at since you're in there...

Just another .02 to add to the pile of tuppence on your shop floor.

[kavadarci1]

Here is where the mark is when I have tdc at 0

I don't know how to verify tensioner if its good

[alabbasi]

You're probably hearing pinging (detonation) which can cause piston damage if you don't address it. This is either be cased by:

1) Poorly functioning ignition system (corroded contacts on the cap causing the spark to jump to another cylinder and firing at the wrong time)
2) Your ignition timing being too advanced
3) Using low octane gasoline

Try cleaning the contacts on the cap and switching to premium or adding octane boosters.

[Pooka]

Originally Posted by Carpenterman

I guess I'll chime in, but it's just speculation.

IMO, a miniscule difference in valve clearance would not cause the noise I heard on the video.

It appears to me that the noise is high in the engine. Since I don't think it is valve train noise, I would think that it could be a wrist pin, that goes from being in compression to tension as the engine goes into "braking" mode as the rpms decrease faster than the ignition/fuel determines. Think braking horsepower, if you know what I mean. The reason you don't hear it when the engine is cold is because the piston/bushing hasn't expanded enough to cause the excess clearance; hence the knock appearing when it heats up.

Or does the clearance get tighter as it heats up? What does everyone say?

Just a guess. At any rate, if it was me, I wouldn't worry about it until it got much worse.

As much as I hate to say it... This sounds realistic. I hate to say it because it is so complicated to repair.

It could be low octane gas, but that would be easy to check. Just start running 97 octane and see if it goes away or diminishes. I always try the easy stuff first and that would be easy.

However, during the late 70's when gas was hard to find, I ran some 87 octane in an engine that needed 102 octane. It pinged and rattled but in a random fashion. Top speed was also about 20 mph. (This was in an Olds 455 engine.)

You can isolate the noise with a wooden dowel rod and a length of plastic tubing. Just find a piece of tubing that fits over the end of a 1/8 inch dowel rod and stick the other end of the tubing in one ear. Then place the other end of the dowel next to the engine. It acts like a stethoscope and will let you isolate a noise to one small area.

In this way you could hear inside the valve cover for a cam noise or you could drop it lower on the side of the block and see if it is a piston or other internal noise. You can also find out just which piston it is.