M104 Tappet noise after rebuild - PeachParts Mercedes-Benz Forum

Boinkers · #1 08-05-2008, 07:49 PM

Hi all.

I have been reading a lot of threads w/regards to noisy tappets. Alas, I haven't really found a good answer as to why my engine sounds like someone has put gravel in it, so I'll give it a try here and see what you might think. The engine in question is a Brabus m104.98x 3.6.

Story so far: Decided to replace valve guidances, engine was smoking badly under acc. and not running very well in general. Took the head off, sent it to a local firm for new valve guides and the usual planing and so on. Put the whole thing back together and started it: klack-klack-rattle-bang, crash...let the engine run warm, no improvement.

Ok, so I thought, fine, I'll need new tappets, bought them (expensive little buggers) off with the cams again, changed them, managed to snap the exhaust cam off into 3 pieces (actually, it wasn't me who did that, but anyway) when rebuilding, again...looking for info on what cam is used in a Brabus engine, thankfully Brabus told me it was a standard exhaust cam, only inlet cam is modified, so, bnought one from a junkyard and assembled the whole thing again.

Klack-klack-rattle-bang, crash, well, you get the idea...

Oil pressure is good, changed oil 2 times lately, not using any fancy synthetic stuff, but it should be ok once the engine warms up, right? Well, no. Noise is still there after warm engine. It is a BAD noise, not subtle at all.

It is not the deep clacking noise from a bad crankshaft either, one thing I WILL check tomorrow is if the noise might come from the timing chain, although I don't think so.

A question: where and how is the oil supposed to enter into the tappets? I know they have a little hole in them on the side, but how does the oil gets there in the first place? Any hoses I might need to check?

Any/all ideas will be accepted with gratitude.

/Pontus

bobs · #2 08-05-2008, 08:54 PM

I'm sure others will add to this, but I believe there's some kind of reset procedure you have to do on the timing chain tensioner on the M104. You might want to check the tension on the chain.

OzC36 · #3 08-06-2008, 11:48 AM

Quote:

Took the head off, sent it to a local firm for new valve guides and the usual planing and so on.

Planing? I hope you didn't shave the head?

Is it possible that the timing chain is one cog out?

(As an aside...Why aren't you using the best quality synthetic oil?)

david s poole · #4 08-06-2008, 12:00 PM

the timing chain tensioner has to come apart as it is a ratchet,you have to take the piston all the way forward and then put it in from the rear of the tensioner and as you tighten it back down the tensioner will set itself.

Boinkers · #5 08-26-2008, 07:15 PM

Thanks all for your input. I have bought a new timing chain tensioner, chain was not tense enough, the old tensioner was a bit limp (even after reassembly the correct way). We'll see if this'll help.