Timing chain + guides question

[hnyc]

Hello all.

I got a '94 E420 a year ago. 160k miles. No paperwork or previous owner information besides the service booklet that came with the car and has nothing since 1995. I only drove it around the block before parking it as the brake pedal sank to the floor and gave that feeling that one never wants to get from a brake pedal. I'm guessing that that is how the previous owner got into the tap in the front and wound up totaling the car. I replaced the master cylinder and leaking caliper which caused this.

I had to pull the engine and transmission from the car for unrelated work.
My intent was to address everything that time dictates to do to these cars with respect to mileage. Among it was the timing chain + rails/guides. Only thing is that after I've put the engine at 45 degrees, all the pins line up. Completely with no adjustment to the engine. Which was not what I was expecting. She did sound and drive great both times I did but I was expecting a little bit of stretch which I'm not seeing.

This car has not been abused but also not maintained well. There is so much varnish in the engine that it's obvious that oil changes were not a priority. Everything is original to the engine except for thermostat, lower pan gasket and miscellaneous vacuum lines. I am doing everything that should be done to this engine before I put it in as I do not want to go near this thing (a V8 has no business being in that car) with a wrench for as long as I have to. Without getting into detail, it's over $1k in parts so far and I'm getting another list ready which could total the same amount. So I'm addressing everything that should be for peace of mind and intended operation.

Should I leave the timing chain alone? If it had stretch I'd have no problem with doing it but spending the time and money to do this when it's not showing any signs of wear seems unproductive. I'm doing the water pump even though it's fine and eyeing the rear seal with the same regard so it's not like I'm trying to put work off. I also might only put 50-75k miles on this car. I'm not selling it but it's also not my only car so there will be rotation going on.

Just looking for some opinions from the experts.

Thank you.

 

[gerryvz]

It would be a bit unusual IMHO at that mileage not to have ANY stretch at all. I'd at least expect a couple of degrees, even with a well maintained engine with regular oil changes. With that mileage, and since you don't have records, it could well be that the chain was replaced in the not too distant past, which is why it is not showing any stretch.

As long as you double-check and confirm that the chain is not stretched beyond a reasonable amount (or in your case seemingly not much at all), then I'd leave it alone. I'd be more concerned about the chain rails' condition, as well as the tensioner. Did you check the rails' condition when you checked the timing chain stretch? As long as the rails aren't too dark, you are probably OK at 160K miles. Then again, it could well be that the rails were changed out if the chain was, previously.

Are the brakes all good now?

Also, you mentioned the "rear seal" -- are you talking about the rear main (crankshaft) seal of the engine? That isn't a super common leak on these engines, and if you did need to replace it, the job would require removal of the transmission to access it. The front crank seal is MUCH more common as a leaker/seeper on these engines than the rear -- tell me about it, I've been putting off doing my front crank seal on my E500 for the past few years.

If you're not talking about the rear main seal, which "rear seal" are you speaking of?

The water pump at that mileage is a prudent thing to do. Definitely replace the thermostat with a new Behr or Wahler unit while you're at it. Not sure if your fan clutch is original, but if it is, may not be a bad thing to also replace at that mileage. You can go factory ($$$$) or aftermarket ($$), but as noted here the aftermarket requires a different center bolt, which you can get at any hardware big-box store.

 

[hnyc]

Thanks for the reply Gerry.
I was thinking the same thing but the chain has varnish on it too. And the reason that I spoke of its originality was because of its seemingly untouched state which means that I didn't see any socket/tool marks on any of the fasteners that would indicate this work was done. I believe that this car has been largely untouched since it was new.
All the pins line up. The rails look ok. Dark but all there. The tensioner I haven't tested. I'm assuming there's a method for this?
The water pump is a Mercedes. I was going to put in a Graf one but I was told that the V8 should get an original unit.
And yes I was talking about the rear crank seal. It's dry which is why I'm wondering if I should leave that alone but it's already exposed so that question arises as well. The front seal I replaced earlier this year as that was certainly leaking.
The engine is on a stand right now and the transmission is on a bench. The only reason for this is that I had to originally do the reverse clutches on it and I snapped a bolt in the d/s manifold trying to get the crossover pipe off in attempting the transmission removal. I couldn't remove the manifold while on the engine. I know there's a WIS for this and trust me I couldn't do it with the mount disconnected and engine tilted opposite etc (that's why I commented on these engines having no place in this car) so everything came out. That's why in this state I'm addressing everything actual and potential because I don't want to go in there again sooner than I absolutely have to.
The fan clutch is original to the car. I was debating its functionality but reasoned that since the car was in the desert that if it was not working it would have necessitated a change by now. But maybe it does need to be replaced.

 

[gerryvz]

Aaah, I didn't know you had the motor out and on a stand. That changes some parameters.

At that mileage, seeing as you have the rear main seal exposed, I'd go ahead and do it. It's cheap, and an easy "while you're in there" job.

Replacing the M119 timing chain is a bit of a PITA, and there are some special tools that make the job go easier. Since the front of the motor is exposed, I'd go ahead and replace the chain, tensioner, and rails as a matter of course then. You will never have things easier to get at, than right now. And I'd also consider (seeing as the motor is out) doing the lower rails as well, though this requires removing the front timing cover.

Since the transmission is also out, I'd go ahead and re-seal it externally. @gsxr and @JC220 have posted a lot of info very recently on this very topic.

The good thing about the fan clutch is that it CAN be done with the radiator in the car, but it's much easier if the radiator comes out. But seeing as your have the engine out, and if money is not a big issue at this point, then I'd go ahead and replace it. Otherwise, if you think it's still got life left in it, it's certainly doable with the engine in the car, at a later time.

I think you can get away with a Graf water pump, unless you want to pay the bucks for a factory unit. I believe the factory units that you can buy are rebuilds/refirbs at this point -- they are not available as "wirgin" units. They are about double the cost of the Graf units, but perhaps double the price is worth a bit more peace of mind as opposed to going aftermarket with the pump.

Other things I'd consider checking (for replacement, if needed) would be the belt tensioner and various pulleys on the front of the engine. Also the motor mounts -- you'll NEVER find them easier to replace than now.

Personally I tend to be more of an "overkill" guy than just doing the bare necessities required, but if you are going to keep the car then it is worth doing the extra work. If you don't plan to keep it, then I'd just do what you need to and put it back together. You said you are inclined to keep it and drive it for the foreseeable future, so I'd err on the side of doing the work now.

 

[gsxr]

If all the cams pin simultaneously at 45°, it's likely that the chain and/or guides were replaced. I would leave the chain alone, but inspect the rails/guides visually. If intact, leave them alone also. Drop the lower oil pan to inspect for rail debris, and while the pan is off, replace the O-ring seal for the level sender that pokes through the side of the block (common leak). Or replace the entire sending unit (Hella/VDO), it will come with a new O-ring.

Otherwise, while the engine is out: replace the front crank seal (photos here), all vacuum tubes/hoses, all power steering hoses (ESPECIALLY the straight hose along the frame rail hidden by a heat shield), check the steering box for leaks, check the idler arm for excess play (0.5mm is limit). If the rear main is bone dry, I'd be tempted to leave it alone, it's a moderate-size can of worms if you go there... find the old thread on the forum discussing this in detail.

Don't forget new copper seals for the valve cover bolts, torque to ~10Nm and go over all of them several times with the torque wrench - only OE/Genuine gaskets, no sealant applied. Re-seal the cam solenoids while it's apart, replace the PCV tubes if not soft (this can be done with engine in the car later). If the engine mounts are not good/recent, new OE only, yes they cost a small fortune but you won't have to touch them for another 100kmi with new OE installed. Aftermarket are all Chinese junk now. Also remember that some bolts need anaerobic sealant applied or you'll get oil leaks, specifically the bolts for the air pump bracket (photo below), possibly one or two others I'm forgetting.

Transmission - replace EVERY external seal. Every single one, including front pump O-ring and output shaft seal, and selector shaft seal. This is a breeze on the workbench, a nightmare in the car. Remember the trans should pull up flush against the block with fingers only, if not, the converter isn't fully seated. If you use bolts to pull them together it will destroy the pump. Converter bolt flange face should be 35mm in from the face of the trans bellhousing.

Brown varnish on everything isn't terrible, it just means the engine likely lived on dino oil for most of its life. What you don't want to find is thick sludge, which is bad. Seach the forum for "Hollyweird" for photos of severe sludge. Fan clutch, leave it alone for now and see how it works in summertime. There are thread upon threads discussing fan clutch operation; worry about it later if the engine runs over 100C frequently.

There's another old thread on the forum where someone (Ricardo?) asked the same question you did - what to replace with the engine out of the car. Might find more info in that thread.

 

[hnyc]

This is tough. I want to change the chain and I wish it had given me some misaligned marks so I could justify it. Now it's just replacing something that shows good. And who knows for how long? There are engines out there with over 200k with the original chain and rails on. If I do it though, I'm going to do the chain and the upper rails and leave the lower ones alone. I already did that front seal and don't want to remove the cover and fuss with the head gasket's placement. I also can't remove that crank bolt/hub with it on the stand. 1/4 of the force needed to remove it would tip the engine over!
I'm going to mull this over. Thanks for the advice.

I might have been a little confusing as I already have a water pump. It's a Mercedes unit and it is indeed remanufactured. Right down to some very small pitting on the mating surface!

 

[hnyc]

GSXR just saw your reply. The power steering hose you mentioned was indeed leaking. I removed the old one with the engine in the car and couldn't imagine this being done normally. I had to double nut a clamp just to loosen it from the underside as I couldn't get a socket or screwdriver from the top. Clearly installed at the factory pre engine installation. I'm redoing everything you said including the p/s heater hose as I couldn't get to that clamp with the engine in place either.
The mounts were replaced in '06 (I'm assuming going by date code) with BOGE units, and while I'd like to keep them, one of them has a small tear in it so I'm replacing them.
I've seen some good posts for engine assembly and will refer to those as I can find them.
If I can't, I will ask for sure.
Thank you.

 

[gsxr]

Chain failures are exceedingly rare. And if it isn't stretched, it doesn't need replacement. IMO, a lot of people replace the chain when the real fault is broken guide rails (which will show chain "stretch", and the cams not pinning at 45°). There are M119's out there with 300-500kmi still on the original chain. Don't lose sleep over it.

If the front crank seal was already replaced, and is still dry, great. Otherwise, to remove the 27mm nut on the engine stand you use a high-torque impact wrench. Re-installing would require the final torque to be done after the engine is back in the car. But if the seal isn't that old you could skip this. It can be done with the engine in the car.

 

[JC220]

The important thing to understand is having the m119 V8 out of a w124 chassis is an opportune time to get a lot of deferred work done. That is parts that commonly fail and require replacement. Given this car has 160k miles and is 26 years old this is why it makes sense to do some additional work with free and open space to work on the motor VS spending much more time and frustration in the car or not being able to do some items at all without having to pull the motor again.
These are the items I would advise on doing with the motor removed;

Updated Oil filter housing check valve
Updated Oil pickup tube
Clean out sump pan (Very likely to have timing guide shrapnel)
All 4x upper timing chain slide rails (I see you have no stretch – and as Gixer states these are common to fail. I would renew them anyway when in there. Even if not currently broken) The guides behind the timing cover do not break and generally do not require replacement unless very high miles.
Front & rear engine main crank seals (If front is less than a year or two old then leave it)
Oil level sender O ring
Inaccessible power steering hoses
Re-seal Power steering pump if weeping
Water Pump + T Stat
Fan Coupling
Alternator brushes
Belt Tensioner + belt
If oiler tubes are plastic – replace them with aluminium versions
PCV Valve + Hoses
Valve cover gaskets
Camshaft Magnets (Suggest a look at - How To on this)
Valve Stem oil seals can only be done with the motor outside of the car. These WILL be hard and not doing much sealing at this stage, mine were bad. Big job though! (Can be done with the heads on)
Distributer Insulator Cups
Engine and Transmission Mounts

Transmission Pump seals
Transmission re-seal – see recent “How To”
Shifter rod bushings
Flex Disc with SGF only

PS I have done this and more myself recently. Refer to my owners thread and How To on 722.3 transmission re-seal.

 

[gsxr]

I think by 1994 they came with the updated oil filter check valve. A new rubber oil sump pickup would be nice if the original one is there (likely fossilized, if never replaced). You'll find out more when you drop the lower oil pan for inspection.

 

[hnyc]

Hello all again.
Small update.
I got the lower pan off and there is not one piece of plastic from the guide rails. I am really tempted to leave them alone but I don't know. Everything on the car is pretty undisturbed which makes me think that they haven't been touched. But still this isn't typical to see no wear. The plugs look ok although the electrodes look a little low, so normal wear. It took a bit of work to get them out almost to the point where it was concerning me but I see the threads look ok.

Thank you all for the help in this and I know this is somewhat repetitive of a thread but you always feel like your situation is different.
I am taking into consideration everything that was mentioned by you all and will address it as the reassembly proceeds so if it's not mentioned here, it's not because I didn't read it.

And now for the questions.

1) The rear seal is leaking from the case/carrier where it meets the block. So that has to get done even though the rubber itself is dry.
Do I replace the upper pan gasket since "I'm there already"? And I'll assume I can get away with replacing just the seal without getting a new carrier? I got a new carrier for the M104 but that was under $30 and this one is over $300

2) Can I re-use the exhaust manifold bolts? Usually I just get new ones but these are ridiculously expensive. I could get ARP fasteners three times over for what these list for. Not to mention the deep washer ones that sit in the middle which are said to be NLA. Keep in mind that not being able to access a manifold bolt is why the engine came out in the first place so I'm definitely not replacing it or able tighten a couple of them it once it's back in.

3) Any leads on tools for doing the chain rails? I don't see anything from Sir, Schley Samstag or Baum. And while on that topic, I might do the valve stem seals. I unwittingly blew some sand in the d/s cam area thinking the valve cover was sitting squarely on the head and it wasn't so... yeah. All that has to come out for some cleaning. So, anyone have leads on tools for that too as I don't see anything for the spring depressor and I'll assume the stem seal is a typical replacement.

Parts sourcing

4) Does anyone have the part number for the PCV hose holding clip at part number 140 on the EPC? It clips into the fuel rail housing. All hoses are getting replaced btw. I thought I could save the connectors but those are just snapping off (where is that throwing money emoji??)

Also for the alternator brushes mentioned above? The alternator has been replaced (Remanufactured Bosch stickered unit) but I might as well do it again to carry it forward a little longer.

5) Any good wiring/hose conduit that is available that is of good quality? Anything near the engine is disintegrating.


I think that's it for now.

I will be redoing the transmission resealing. I should be ok on that as I redid the other W124's transmission when it was out last summer and so far no leaks and it's still somewhat fresh in my head.

 

[gsxr]

#1: MB does not sell the carrier with seal pre-installed. You install a new seal and use MB black sealant (Loctite 5900?) for the carrier to block. Since the engine is out you could replace the upper oil pan gasket to block but that's a ton of work and probably not necessary.

#2: Don't see why you can't re-use the bolts...

#3: MB FSM shows the chain being replaced with wedges. It sucks. BT, DT. Photo below.

#4: Photo attached below.

#5: Click here.

 

[hnyc]

So it seems that the guides (and chain) are indeed original to the car. I tried to unsnap the top rail apart and that’s exactly what happened to the plastic teeth holding it together. So its brittleness along with other telltale signs tells me that this is the first time that this has been opened.
So upper guide rails will be replaced along with the tensioner (most likely). Needing to get the manifold off though led me down a path that perhaps I shouldn’t keep going on.
Seriously considering replacing the valve stem seals (25+ year old rubber etc) and removing the intake manifold has showed me how “dirty” this engine is. There is carbon/oil caked on everywhere in this intake passage.
Normally I’d just say ‘screw it’ and pull the heads off and have them cleaned alongside everything else. But someone whose experience and ability (especially with these engines) far eclipses mine told me to just leave it alone. These are dirty engines and they run well even with caked on deposits.
But it bothers me, and the time I’ll spend cleaning whatever a long stemmed swab will allow me to might be better spent removing them and having them hot tanked for a thorough cleaning.
Or do I just clean up the spark plug holes and threads as well as mating surfaces and be done with it?

 

[gsxr]

If the deposits will wipe out with minimal effort using solvent and rags, sure, clean what you can. Otherwise, listen to the person who gave you the advice. The photo shows a thin layer of deposits; nothing that would restrict airflow enough to actually affect performance. It's mostly aesthetics.

The valve stem seals could be a complicated job, I've never done it personally (yet). Be careful if you go there, worst case if you accidentally drop a valve, the head may have to come off to retrieve it.

Since you have the intake manifold off, might as well replace the rubber donuts between the upper and lower halves.

 

[hnyc]

If you’ve never done it, no reason for me to touch an engine that wasn’t smoking to begin with.
It does bother me to close an engine up that dirty, but if I did this as ‘work’ it certainly wouldn’t be the first time so I’ll live.
The reason the manifold came off was because of those same doughnuts - which led me to see the buildup of carbon in the passage which led me to...
What a web this is

 

[JC220]

So it seems that the guides (and chain) are indeed original to the car. I tried to unsnap the top rail apart and that’s exactly what happened to the plastic teeth holding it together. So its brittleness along with other telltale signs tells me that this is the first time that this has been opened.
So upper guide rails will be replaced along with the tensioner (most likely). Needing to get the manifold off though led me down a path that perhaps I shouldn’t keep going on.
Seriously considering replacing the valve stem seals (25+ year old rubber etc) and removing the intake manifold has showed me how “dirty” this engine is. There is carbon/oil caked on everywhere in this intake passage.
Normally I’d just say ‘screw it’ and pull the heads off and have them cleaned alongside everything else. But someone whose experience and ability (especially with these engines) far eclipses mine told me to just leave it alone. These are dirty engines and they run well even with caked on deposits.
But it bothers me, and the time I’ll spend cleaning whatever a long stemmed swab will allow me to might be better spent removing them and having them hot tanked for a thorough cleaning.
Or do I just clean up the spark plug holes and threads as well as mating surfaces and be done with it?

When you are already in that far and the motor outside of the car it's really not much more effort to pull both heads and have a machine shop properly clean the heads and manifold. There are EGR tracts in the block which were plugged solid in mine too. With the heads off I could properly clean them out.

Don't attempt to replace the valVe stem seals with the heads in place. It is way too much time and trouble trust me - and the carbon in the cylinders will come loose with the compressed air and stop valve(s) from sealing. This means that mid way you will not be able to remove a valve collet and thus the heads will need to come off anyway.....

This is how the original valve stem oil seals will look like in 99% of m119s by now:



(The only people I know of who has changed the m119 valve stem oil seals on this board are me & Eno FWIW) Seeing the state of these I know it was very much worthwhile to replace them. These are not making an effective oil seal on the stem. Indeed the valve stem was not even touching the rock hard seal anymore. Did it burn oil? Don't know as it was a used motor I bought but again - the picture says it all IMO. From your photos all you need to do is remove the head bolts pretty much and the heads are off....

 

[gsxr]

If the engine is out of the car, you're right, it's not much more work at that point.

One hassle with the engine in the car is pulling the exhaust manifolds. Dunno how much fun that is - never tried!

 

[JC220]

PS if you look in the past few pages of my owners thread you will see many posts and photos of that m119 getting restored

 

[hnyc]

That’s how this whole thing started.
I snapped off a crossover pipe bolt in the d/s manifold end. So the manifold had to come out.
Try as I could I couldn’t get to all the bolts even with the engine mount disconnected and engine tilted all the way to the other side. I have no idea how anyone can do this as I have enough tools to give me the access that I would need. So since I was removing the transmission for the reverse clutch job, I figured pulling everything out wouldn’t be anywhere near as bad as trying in futility to get that manifold out. I replaced the leaky front crank seal before all this because I had no plans on pulling this engine.
JC220 I have seen your thread on the engine work you’re doing. I’m not going that far for sure but maybe maybe will be coming close. Still undecided about the heads. And every single part that had any type of pliability to it in 1994 has snapped or crumbled in my hands upon handling.
Why should the stem seals be any different?
I might just flip a coin and stick to that decision.
Hopefully, no matter what it is.