dmac5356

• Sounds like a lifter
• Varies with RPM
• Using Mobil-1 0W-40 oil
• I eliminated accessories by removing serpentine belt
• Indy shop thought it was valve-related on the passenger side
• I ordered new lifters and a valve cover gasket for that side

I took it apart today - very time consuming! The valve train looked pretty clean. No sludge or debris to clog lifters. I had to tap the old lifters out with a drift. They were tight enough in the rocker arms that I can't see how the lifters can possibly function.

To install the new lifters I oiled them up, but still had to tap them into place. Again, I think they are too snug for the springs to extend the lifter to take up valve train slack. The lifters have a small circlip that might act like a piston ring in the bore of the rocker. This clip may be dragging in the bore. I would think that over time the rocker arm bores would wear larger, making the lifters looser. But that is not the case here. I can also imagine carbon deposits in the bore causing the lifters to stick, but the bores looked clean.

After too many hours of work I started the engine and have the exact same tick, tick, tick that I started with. Advice will be appreciated!

samaritrey

How bad is this tick? any way to get a recording of it or is it to quiet? Also how many miles on the car?

dmac5356

It is pretty noticeable when outside the car, especially at lower RPMs. Inside the car it's much more subtle, but I can still hear it.

Video:
The car has 106,000 miles. I just bought it a couple months ago, but couldn't hear the tick over all the racket the water pump was making! I replaced the water pump myself, and then noticed the ticking.

I obtained the service history from a dealer. The prior owners (2) had all service done at MB dealers at the FSS intervals. Those intervals are long for my taste, but dealers should have used the proper oil and filters at least.

I'm really interested in how snug the lifters should fit inside the rocker arms. I read somewhere about putting a little grease on new lifters to hold them in place while installing - implying that they fit loosely in the rockers. But my lifters (both old and new) fit pretty tight. I can't imagine how they can function this way - and maybe they are not.

Do I need all new rocker arms? Is there a way to hone them a little? How did the bores in mine shrink over the years/miles? Perhaps a manufacturing defect and the prior owners never noticed the ticking?

krazzdav

Lifters are supposed to be snug like that. There are different lifters for intake and exhaust. My C320 does the same thing but still haven't isolated the problem after I changed my passenger side lifters. I have since bought engine ears to pinpoint the noise but haven't gotten around to doing it. Lol
Here's my vid

dmac5356

Yours has a similar sound. I hope we can find out the cause(s) soon.

Yes - the intake and exhaust use different lifters. I ordered and installed 3 exhaust and 6 intakes on the passenger side, but they visually look about the same. The only way I could tell them apart was the packaging.

Everything looked fine under the rocker cover. No visible wear on the rocker rollers, nothing unusual about any of the lifters that I removed. No sludge or carbon or other debris.

I may have to bring it into a shop and pay $$$

dmac5356

If the lifters are supposed to be tight in the rockers, perhaps I should focus on something other than lifter/rocker/valve. Could an injector make this noise?

BigN8

Could also be timing chain or timing gear.

Also good to see another Minnesotan here. Coon Rapids is where I am from.

dmac5356

Could be, yet the chain, guide bars, chain tensioner, and cam gear looked good when I had the passenger side valve cover off.

I'll try listening with a piece of tubing as makeshift stethoscope to see if I can narrow down the possibilities a bit.

The engine runs smooth, and has plenty of power. But the ticking is annoying, and could lead to bigger problems.

I live in Eden Prairie.

dmac5356

Yes - I had ordered and installed 3 exhaust lifters and 6 intake lifters in the passenger side of the engine. Different part numbers, although they look identical on the outside.

dmac5356

No additional thoughts on the ticking sound in my video above?

dmac5356

Today I tried the big screwdriver-as-a-stethoscope test. Touched one end to each valve cover while the engine was running, other end to my ear. I highly doubt the ticking is coming from the valve area. Now I'm thinking it may be coming from the harmonic balancer area (big pulley on end of crankshaft). The pulley has a very slight wobble, but I don't think it is enough to hit anything.

Ideas?

samaritrey

You have ran the car with no belt right?

dmac5356

Yes, per post#1

dmac5356

My next step is to replace the harmonic balancer. It has a little wobble, so needs to be replaced anyway - and maybe it is hitting something in it's wobble (but I don't think so). I have ordered the part and bolt, and the holder tool. I just need to get the large socket - 27 mm correct?

dmac5356

My car is still ticking and it's driving me nuts.

I remain concerned that the lifters fit so tight in the rockers. It appeared that this would prevent the internal springs in the lifters from ever expanding them to take up the slack between the rocker and the valve. I would think they should be just tight enough not to wiggle around, but loose enough that the springs can expand the lifters.

I had brought the car to a dealer a couple months ago... they said that either a piston is carboned up or is severely worn causing piston slap. I had already tried Techron concentrate, which made no difference. Also, if the engine had a ruined piston/cylinder wall it should be using oil like crazy - which it isn't. The oil filter has been clean with no metal. I could boroscope the engine to verify, but I don't think the dealer was on the right track.

Possibly rod knock? That would be bad!

Searching the Internet I find people with similar ticking problems, but they haven't posted their ultimate solution.

dmac5356

Any progress?

Redwood415

It's not a lifter.. They are cam followers or tappets
you only refer to them as lifters on pushrod motors with cam in block and push rods. OHC motors don't operate that way.
a little ticking is normal on high mile M112 motors, It is more common on engines that have had incorrect oil type or viscosity during their service life.
We have a M112 in an old E320 with 306,000 miles and it is still as quiet as ever, heads have never been off.

my two cents

Pawel83

Hello. I know it is very old thread but I was having the same issue and I did a lot if searching all over internet. I did change oil multiple times 5w40, 0w40 but that helped olny for few hundred km. I noticed that my cooler fluid is lowering its level slowly so finally I bought some xado cooler fluid anty leaj and added it to the fluid. After aome time fluid stopped getting low and I was astinished to see that the noise has gone. It is about 5000 km and still the engine is calm. Seems like the was a leak of coolant to the oil...