A Class slight Engine Wobble at tickover solved but how?

[Submariner1]

as reported at tick-over, which was a tad slow say 550 rpm , the engine wobbled slightly.

I changed the oil to 5W50 (from 0W40) and the rather old air filter.
The tappets got instantly quieter, and the chain noise I would normally experience for about the first 2 minutes after the first start up of the day, (and then went away), seemed very much quieter.
But the engine still wobbled.

5 or 6 start ups later, the next day the engine wobble was 95% gone!

OK I expected a quieter tappet noise with thicker oil ... and got it.

As the new air filter didn't instantly speed up the tickover, and cure the wobble. I assume it wasnt a chocked air filter causing slow tick-over, and hence the wobble.

My only deduction is, after changing the oil; gradually as the leaking Tensioner leaked more 0W40, which would be replaced by 5W50, everytime it started the percentage of 5W50 oil in the tensioner rose.
And the thicker oil made the seal more and more effective. To the point, at tickover the tensioner was working well enough to deliver proper timing and the engine is now smooth.
( note at higher revs the engine always went smooth before ).

Looks promising for the Monday Tensioner replacement, and the air intake and breather clean up

 

[L John]

Maybe the new air filter did the trick but the software took it's time to adapt to the airflow and lambda sensors? Assuming it has them?

 

[mattkh]

Looks promising for the Monday Tensioner replacement, and the air intake and breather clean up

thank you for the feedback. What brand oil is it?
Once I get my hands on an old tensioner, I am going to investigate if it has a one-way valve in it for the oil. I am inquisitive as to how the engine oil gets into the tensioner through that tiny hole as well.

 

[Submariner1]

as reported at tick-over, which was a tad slow say 550 rpm , the engine wobbled slightly.

I changed the oil to 5W50 (from 0W40) and the rather old air filter.
The tappets got instantly quieter, and the chain noise I would normally experience for about the first 2 minutes after the first start up of the day, (and then went away), seemed very much quieter.
But the engine still wobbled.

5 or 6 start ups later, the next day the engine wobble was 95% gone!

OK I expected a quieter tappet noise with thicker oil ... and got it.

As the new air filter didn't instantly speed up the tickover, and cure the wobble. I assume it wasnt a chocked air filter causing slow tick-over, and hence the wobble.

My only deduction is, after changing the oil; gradually as the leaking Tensioner leaked more 0W40, which would be replaced by 5W50, everytime it started the percentage of 5W50 oil in the tensioner rose.
And the thicker oil made the seal more and more effective. To the point, at tickover the tensioner was working well enough to deliver proper timing and the engine is now smooth.
( note at higher revs the engine always went smooth before ).

Looks promising for the Monday Tensioner replacement, and the air intake and breather clean up

Just come back from the A Class specialst he fitted the timing chain tensioner.
Mine was leaking down overnight, so took about 2 mins to pressure up the piston. Then it was fine.

Verdict new Tensioner ... absolutely sweet coupled with the 5W50 engine sounds like she did when she was 2 months old. Seriously.
Even the specialist said it sounded excellent! As good as they get.

 

[Submariner1]

thank you for the feedback. What brand oil is it?
Once I get my hands on an old tensioner, I am going to investigate if it has a one-way valve in it for the oil. I am inquisitive as to how the engine oil gets into the tensioner through that tiny hole as well.

I used Mobil1 5W50 MB 229.3 5L £46 delivered Engine Oils Direct (official distrubutors .. checked with Mobil) recommended by Mobil and my specialist.

Quote “5W is almost as free flowing as 0W in the UK climate, and the 50 ensures the oil film stays intact at very high temps, like a 50 grade will, so ideal for “non perfect” engines. “

All I can say is it delivered a dramatic result. I am sold!
Absolutely made the engine sound like it did when it was 2 months old, the specialist also said it sounded excellent.

He left the old Tensioner in the box ... hmmm looks like one top nut with a seal/washer ( available from MB ).
I was going to undo it, and see if one could replace the seal .. just out of interest, as we have the new one fitted.

The oil gets into the small slant cut hole by oil pump pressure, and there is a one way valve in there. So once full of oil it is ****** hard (impossible) to press, whereas the new (empty of oil one) was easy to push in the spring loaded piston.
Definitely do not prime this Tensioner with oil prior to fitting ... you would have it at full extension, rock hard and never be able to fit it!