Misfire at idle, ignition components replaced

[JDAMG]

 

[JDAMG]

Sadly it has been a long time, but as the pictures above support, it is time for timing chain tensioner, guides and a chain. Ordered my parts. Should be in tomorrow and car will be back on the road soon. Has been sitting in the work parking lot since September. Can't wait to get it back and running properly.

 

[gsxr]

The plastic chain rails are definitely toast and all should be replaced.

Have you measured each camshaft to see where each one pins (1 at a time) relative to the indicated degrees at the crank/balancer? If not, you should do this BEFORE taking anything further apart.

While it won't hurt to replace the chain & tensioner, is there any evidence the chain is defective or excessively stretched? You can't measure chain stretch without either removing and comparing total length with a new one, OR measuring degrees of cam error with new guide rails installed. I assume you know that rolling in a new chain is not for the faint of heart. It isn't a simple job like on the inline 6-cyl engines.

 

[JDAMG]

Yes we have measured, three of the four cams are out of time. Three are missing the marks at 0 degrees, one is still in time (the very furthest passenger side). Admittedly this is where my knowledge ends, fortunately my friend/coworker/MB technician has done a few of these so I am leaving it in his capable hands.

 

[gsxr]

Hmmm. The cams should pin at 45° BTDC. If they pin (for example) at 40° BTDC, that would indicate 5° out of time.

One tooth on the chain translates into 20° at the crank, so (for example) if a cam was 1 tooth out of time, they would read 25° BTDC at the crank, etc.

Maybe see if he can explain how far out of time they were. It would take multiple teeth off (40+ degrees) more than one tooth off (40 degrees or more) to cause a real difference in engine operation. Edit: As described below, the engine may run almost normally with one or more cams only 1 tooth / 20° out of synch.

 

[JDAMG]

Based on the conversation I was listening to, as my tech and shop foreman were discussing, two of the cams were about 1 tooth out, one was a bit more or less (not sure sorry) and one was lined up correctly through the holes on the camshaft.

 

[JC220]

... (snip) It would take multiple teeth off (40+ degrees) to cause a real difference in engine operation.

It's funny that in reality it actually does take an old mercedes engine to be off timing by several teeth to cause running issues.

Compare that to modern cars where the tolerance is so finite they require timing chains & guides replaced as low as 25k miles.

 

[gsxr]

It's funny that in reality it actually does take an old mercedes engine to be off timing by 40 degrees or more to cause running issues.

Compare that to modern cars where the tolerance is so finite they require timing chains & guides replaced as low as 25k miles.

I learned this the hard way. I bought a car years ago where it seemed one of the cam adjusters was not working, the idle did not become rough when one was energized, but the other worked normally. After pulling the valve covers it turned out 3 of the cams were ~20° out of time.

I was thinking they were 2 teeth off (40°) but checked my records and nope, it was "only" 20° max. Not sure if 40° would cause piston/valve interference, but also don't know how common it would be to have skipped more than 1 tooth? I'll edit the previous post to clarify!

 

[JDAMG]

So getting ready to get started on this project: Any input would be appreciated as always.


We plan on replacing all of the timing chain guides, so the front timing cover will be coming off. I have been reading some slightly horrific stories about this, and it is making me second guess replacing the lower driver side guide. But at the same time, seeing the condition of the other guides, I would rather have everything be new. So I think our plan is the correct decision.

Any tips I should pass along to my technician? He is excellent at this kind of work but it has been quite a while since he has been this deep in an m119. Of course he will have access to WIS and all the other available MB data and diagrams.

I also ordered the cam seals, crankshaft seal and a new water pump. The thermostat was replaced recently so not doing that again. Is there anything else I should consider?

And i guess beyond that... wish us luck! Hoping to be back behind the wheel in a couple of weeks.

 

[gerryvz]

RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh | Member Roadtrips and Project Journals

What with the current "self quarantine" imposed, I thought it a good time to begin a very long-standing project -- the complete refresh and cleaning of the top end of my M119 engine. Note that my E500 has 143K miles on it. There was ZERO issue with running, other than the following small...

www.500eboard.co

 

[JDAMG]

Thank you Gerry. Amazing detail in that post, extremely helpful as always.

 

[gerryvz]

Thank you Gerry. Amazing detail in that post, extremely helpful as always.

I didn't do the front cover nor lower rails on my car, but as I found one of my upper rails was broken. I'd definitely do the front crank seal, the cam seals, and any other soft parts including vacuum lines, intake manifold donuts and such. The cam solenoids are also an excellent replacement, as they do weep and then leak. Also things like your throttle cable, if that is original. All hoses and boots. I got into what was originally mostly a front crank seal, and it spiralled into a 5-month project and the replacement of everything that wasn't metal under the hood, essentially. Definitely do a new water pump if yours is original. Also the smog pump hoses will be fossilized, so good to do them as well as coolant and heater hoses if not replaced. I even replaced the foam squares under the headlamp buckets and foam strips around the headlamp buckets (which @Jlaa needs to do on his car).

Good luck on avoiding scope creep. I was not successful at that.

 

[JDAMG]

Fortunately I have done quite a bit of that already. But I am sure it will snowball. I have replaced in the last two years, the intake manifold gasket, injector seals, distributor caps, rotors and insulators, all coolant hoses, all of the breather hoses, thermostat, coolant reservoir, belt and belt tensioner.

I am sure there is more, and definitely added some parts to the list thanks to your project post. I have also replaced some of the vacuum lines but will do doing the rest. Didnt even think about the throttle cable, or smog pump hoses.

Just hoping all goes smoothly, I really miss driving the .034. I did pick up a 202 chassis to daily drive recently, much less robust but I visit the gas station less. When the .034 first went down I was daily driving my r129 sl600

 

[JDAMG]

 

[JDAMG]

Making progress. Here are some of the items that we will be replacing during this teardown.

Timing chain, timing chain guides, cam bridges (oil tubes), oil filter housing seal, front cover o rings, dipstick o ring, lower oil pan gasket, ac compressor seal, power steering reservoir seal, crankshaft seal, water pump, cam seals.

Also going to clean up the engine from the years of caked oil and grime, as much as possible but it certainly wont be to @gerryvz standards.

Not related to the timing chain repair, but also replacing my old steering wheel with the nice sportline wheel from member @duuder . Also replacing the air intake sensor that has a broken clip.

Each day that list is growing. We finally got the timing cover off without incident but took a few hands to get it off properly. Hopefully it will start going back together soon.

We also went the remove the camshafts route to do the chain fyi.

 

[gsxr]

Here are some of the items that we will be replacing during this teardown.

Timing chain, timing chain guides, cam bridges (oil tubes), oil filter housing seal, front cover o rings, dipstick o ring, lower oil pan gasket, ac compressor seal, power steering reservoir seal, crankshaft seal, water pump, cam seals.

I'm seeing factory aluminum oil tubes in your photos - why would you change them? They don't wear out.

 

[JDAMG]

I'm seeing factory aluminum oil tubes in your photos - why would you change them? They don't wear out.

See I had this argument with my MB techs... I said lets leave them, they are aluminum. They argued that Mercedes revised to the plastic that can collapse but were revised for a reason.

Is there a rubber seal on the aluminum tubes that can also be brittle and cause an issue after 30 years? I dont know bc we have not removed them yet... that was also their angle on replacement.

 

[JDAMG]

Ok… just went into the shop. We are leaving the aluminum tubes. This has been well documented on this forum.

 

[gsxr]

Phew. Good call! And yes, you can replace the O-rings on the tubes if desired. I have yet to find any that were brittle or fossilized though.

 

[JDAMG]

Phew. Good call! And yes, you can replace the O-rings on the tubes if desired. I have yet to find any that were brittle or fossilized though.

Thank you @gsxr . They will stay right where they are! Was also going to replace the oil pump but it is on galactic back order. So no go. I don’t believe it is a high failure part and was not having any issues.

 

[JDAMG]

Okay so we have run into an issue. Could not get the timing correct due to a seized left side intake cam adjuster. We removed the camshaft, took off the adjuster, it does not move freely within itself. It also will not go back on to the teeth of the camshaft. Not sure where to go from here.

 

[JDAMG]

 

[nocfn]

Is that a broken sprocket? Did it happen due to stretch of the chain, jumping time or guide breakage?

 

[gsxr]

Okay so we have run into an issue. Could not get the timing correct due to a seized left side intake cam adjuster. We removed the camshaft, took off the adjuster, it does not move freely within itself. It also will not go back on to the teeth of the camshaft. Not sure where to go from here.

I can't tell from the photo if the adjuster is damaged or repairable, but worst case, get a good used one and swap that in. Never heard of one failing before. Weird.

 

[JDAMG]

Ordered a new one from Mercedes. Coming from Germany so it will be a week or three.

 

[JDAMG]

So it has been a while, but the job is done. I have some progress pictures I will try to post but now I am dealing with a new issue that I will post separately. The job was a success. Full front cover reseal, new chain, all chain guides, cam adjuster on the driver side, fixed a trans leak, replaced cam seals, air intake sensor, upper oil pan gasket, water pump, crankshaft seal, ac compressor seal, dipstick o ring, oil filter housing seal.

It also had new coils, injector seals, distributor insulators, beru ignition wires, caps and rotors and plugs as a part of the diagnostic process.

It has been a tough run with the 400e, and now I just have one nagging issue left, for now....