Excessive wear on rocker arms

[sens]

Hello Pagode friends!

My engine was producing again some smoke on acceleration and hesitating a little during acceleration on my last trip.
I checked the valve clearance and discovered that it was way out of spec after only 1000 km! Inlet 0,15 mm and outlet 0,3 mm. (double!)

The engine is overhauled 2000 km ago and the FIP has been checked by a professional.
Oil pressure is OK.

I found out that there was excessive wear on all the rocker arms. Up to 0,5 mm of material disappeared, explaining the huge valve clearance.
A high valve clearance may explain bad "breathing" of the engine, I guess.
The oil pipe above the rocker arms is clean.

On the (new) cam shaft you can see some traces of the bad rocker arms, but fortunately no big wear.

I attached four pictures. The first two showing one of my rocker arms. The third picture is of a rocker arm on the website from SLS-hh having the same identification number. The last one is the cam shaft.

It looks like the heat treatment of my arms was much weaker than the ones sold by SLS-hh.
Could a bad heat treatment be the reason of the excessive wear?
Or is there a lubrication issue? However engine rebuilt 2000km ago; oil pipe clean... No dry cam shaft.

Thanks for your support, Pagode friends!

[mdsalemi]

What kind of oil did you use and what kind of break-in procedure did you use after the rebuild 2000 km ago?

[Pawel66]

I am not an expert on this, but it seems to me that this kind of damage after such a short distance may not be due to slight difference between two types of oils that may be in question here or by wrong camshaft run-in procedure (20min at 2500rpm or so, do not remember exactly).

If I saw it on my engine I would have thought something was fundamentally wrong there, as if valve movement was restricted or something (piece of metal) got between camshaft and rocker...

Also, I am not sure what clearances you set. On cold engine it should be 0.08mm and 0.18mm (230/250SL) and 0.1mm and 0.2mm (280SL), so not exactly double...

Sorry to say, and again, I am not an expert, but the camshaft may be gone... maybe engine needs to be flushed to get rid of metal particles form rocker and shaft...

[sens]

I use 10W30 oil in the engine.
I set the valve clearance at 0,08 (in) and 0,18 mm (out).

I did not follow a specific break in procedure, but I put some oil on the camshaft before starting it for the first time.

What do you think of the rocker pictures? Could there be a heat treatment problem?

I sent the rocker arms to my engine builder and I will report back what he thinks.

[Pawel66]

You are right, there are no heat treatment marks on your rocker...

[sens]

That was my observation.
So badly hardened steel, so excessive wear, so valve clearance problems, so a bad running engine ...

It is a theory...

[MartinK]

I see you are sitting in NL. I recommend to ask at Motoren Ritterbecks in Heinsberg, is is close to NL. He is very experienced with Pagoda Engine family and has knowledge to improve the oil flush on the camshaft and he uses a camshaft cover with a plexiglass "window" to see if the cam is lubricated as it should be. Good luck, but your camshaft needs a rebuild, too.

[sens]

Thanks Martin, good suggestion!

The wear on my camshaft looks minor.
On youtube I see some posts of repolishing the shaft by hand in the engine.
It looks like a do-able method.

The shaft is just 2000 km "old". Worth a try?

Thanks!

[MartinK]

I do not recommend a DIY solution because the camshaft needs to be hardened after treatment. I have good experience with "Campro" for overhaul.

[sens]

I will bring my Pagode to the engine builder.
He will remove the cam shaft and rockers and inspect them.

Probably cam shaft overhaul and new rocker arms, I think.
And check the oil pressure I guess.

I will report back as soon as possible.

Thanks so far for your advice!!!

Halvor

[wwheeler]

Michael just wrote a post with good info on oil and oil that needs to be used with these older engines. It was stated earlier in this post that the oil used was 10W-30, but not if it was one made for older engines with high ZDDP. That would be good info to know.

With heat treating, only a very thin outer layer is hardened. Once that is worn through, the softer base metal is exposed and will wear very quickly.

15 years ago, my original rockers were starting to show very small spots on the wear surface and I didn't want to destroy the cam. I replaced my rockers with an aftermarket brand and do not remember which now. I used the original cam though.  Within a 1000 miles with using the aftermarket rockers, I noticed an unusual wear mark on one cam lobe. I took all of the rockers off and discovered on at least two that there was accelerated wear. See attached.

Yes, I was using Valvoline VR1 20W-50 (Texas) and has a high ZDDP content. After the discovery, I bought rockers from The Mercedes Classic Center and haven't had a problem since. My conclusion is that for high stress components in the engine or elsewhere, I use Mercedes parts. I tried to save some money on the aftermarket and almost destroyed my cam in the process.       

[MartinK]

Yes. Some aftermarket rocker arms are known for their weakness. With or without ZDDP.

[sens]

Thanks for this information!

It looks like I had a chance to try the weaker rocker arms…
Gone after 2000 km…
And a seriously damaged cam shaft…

Attached the engine oil I use.

I’ll keep you posted.

[wwheeler]

That's a bummer. I was lucky that I just happened to spot the rocker arm issue just in time. That was a learning moment for me.

[DaveB]

It's a good learning moment for us, unfortunately at your expense. But it's disgraceful these parts cannot perform their basic function. Can you name the manufacturer?
Not a problem for me, luckily I found these new and cheap years ago.
Does anyone know what the 1J and 9J mean? Maybe just a batch number and not significant?

[DaveB]

I realised there are no blueing marks on mine either but I presume they are genuine and good.
This aspect is certainly something to look out for.

[wwheeler]

Those rockers are long gone. No idea where I got them and that was 15 years ago. It may possible to get rockers with the exact same spec as the ones with the Mercedes logo, but how will you know until its too late. Not worth it to me. Ornamental parts are fine aftermarket. But high stress parts, nope.