Help my brother, for I am his keeper, and his Mercedes 190 hath descended into mechanic's hell...

06HHR wrote: I'm not a professional mechanic and I didn't stay in a holiday inn last night. But, while your basic premise is right, your conclusion is a little off. VCH is correct, incorrect cam timing will have a detrimental effect on compression and vacuum especially on a DOHC engine. What you are forgetting is that when you have an additional camshaft to account for those camshafts have to be in time in relation to each other as well as the crankshaft.

Well, that MIGHT be the case on a DOHC engine, but my 1985 Mercedes 190E is only a SINGLE Overhead Cam, so any change to the cam timing will affect both the intake and exhaust valves opening and closing at the same time and at the same rate. So if you turn that cam a little retarded, it will make the exhaust and intake valves open late and if you advance it, it will make the exhaust and intake valves open early. But regardless the valves shouldn't be open during the compression stroke.

06HHR wrote: Come to think of it, just re-read the first post in the thread, again not sure about benz engines, but I wonder if the valve lash was adjusted properly?

Well, the engine has hydraulic lifters, so there is no real "valve lash" to set on it like on a solid lifter engine. HOWEVER, according to the service manual, there ARE different shims that can go into the lifter mounts in the rocker arms to adjust the clearance of the lifter to the cam and the rocker arm to the valve stem as needed during reassembly of the engine. I'm assuming this is only really needed to compensate for worn components when adjusting the timing on the engine though.

In reply to MailmAn: Bet they mixed the shims up. Even on an engine with a hydraulic valvetrain you still have to set the valve to rocker clearance so you don't wind up with too much preload on the valve (usually what they call "zero lash"). If they did not install the shims in the order they removed them, your valves are out of adjustment and there is no real way to compensate for the different shim thickness.

About the shimming of hydraulic lash adjusters, here's a possibility. Back in my Subaru daze, we got EJ (is that the rocker arm SOHC engine?) heads back from the machine shop with new valves etc which were hard to start, then ran OK, then ran like ass. No amount of fettling would straighten it out. We finally discovered that the valve installed height was not correct and was the source of the problem. How does this change things?

The bleed hole passage in the hydraulic lash adjuster has a limited range of movement. Once it exceeds that movement, either oil can't get in or it can't get out. Either way, the valve lash is now off. This gets worse as the engine runs more, in the Subarus it was holding some of the valves open when hot. The oil may or may not have bled off as the engine cooled, it was pretty random. Sending the heads back to correct the installed height got it straightened out.

I'm not real familiar with the lash adjuster layout in the 190 head, but if the head was sent out for machine work, the installed valve heights were not checked, the shims or lash adjusters were mixed up (or even put back in the same place) it may be having the same issue. How to check/fix? Disassemble and investigate.

Curmudgeon wrote: We finally discovered that the valve installed height was not correct and was the source of the problem. ... The bleed hole passage in the hydraulic lash adjuster has a limited range of movement. Once it exceeds that movement, either oil can't get in or it can't get out. Either way, the valve lash is now off. This gets worse as the engine runs more, in the Subarus it was holding some of the valves open when hot. The oil may or may not have bled off as the engine cooled, it was pretty random. Sending the heads back to correct the installed height got it straightened out.

Good call, Curmudgeon. I was actually wondering this myself as I was trying to wrap my head around how the hydraulic lifters work in my Mercedes engine. I thought they were just oil filled and had some leeway to compress as needed if the valve was already opened all the way but the cam was trying to push it open further somehow. Turns out it is a LOT more complicated than that and there are a lot more factors to take into consideration that can fail. There is actually a test outlined in the service manual for the hydraulic lifters to be sure they will hold pressure for a certain amount of time and then bleed off pressure as well. If they are not doing both properly, then the lifters have to be replaced. If I have a lifter that is either not holding pressure or, conversely, not releasing pressure, when they should be, that could be causing more problems as well!

I KNOW they didn't replace the lifters in the engine because the shop told me it would be an extra $400-$500 to replace them and he said they don't USUALLY go bad and there should be no reason to replace them, so I declined to have them replaced at the time. If I end up having the whole engine redone the right way, I'll probably spend the money and replace them all just to be safe.

So, lets think about this for a minute ...

Lets say you have the timing off, whether it be advance or retarded ... It does not matter.

When the valves are closed, the piston will not be at TDC. Therefore you will not have the same compression ratio. And lower compression numbers.

Run an engine retarded for a while and you WILL mess things up. Your EGTs will skyrocket. Run it advanced and you can break ringlands very fast from detonation.

Is it in my head or a bunch of people are trying to help you understand your problem and you are brushing them all off. It sounds like you know more than everyone else here ... Not even sure you need our help.

Maybe I am incorrect and took it all wrong.

And no, I am not justifying your mechanic.

In reply to Slippery:

He may just be a bit touchy and trying to enforce the fact that he is knowledgeable about the workings of his car, and rightly so. I assume the mechanic has told him repeatedly that the mechanic is all-knowing and he is either misinformed or completely inept.

Slippery wrote: So, lets think about this for a minute ... Lets say you have the timing off, whether it be advance or retarded ... It does not matter. When the valves are closed, the piston will not be at TDC. Therefore you will not have the same compression ratio. And lower compression numbers.

I'm sorry, but that doesn't make any sense to me. To quote one of my links about engine timing, "The diagram above illustrates the conventional 4-stroke cycle of an internal combustion engine. It can be seen that both the intake and exhaust valves remain closed during the compression and ignition phases of the cycle. It is therefore usual for any discussion of valve timing to focus on parts 1&4 of the cycle, that is the valve motion in the periods either side of piston Top Dead Center (TDC) on the non-firing stroke."

So, to me that means that even if the timing of the engine is off by a significant amount (20-30 degrees), both valves will still be closed during the important compression stroke where we are actually measuring the engine's compression. So far, no one has been able to effectively explain to me how it could be any different, besides maybe on a DOHC engine with one camshaft dramatically off by more than 90-100 degrees, but then the engine just wouldn't run at all I wouldn't think. Barring one stuck valve on one cylinder making that one cylinder misfire and having the engine run erratically (especially noticeable on a 4 cylinder), there does not seem to be any way to have an advance or retarded cam timing affect the compression of the engine.

Slippery wrote: Run an engine retarded for a while and you WILL mess things up. Your EGTs will skyrocket. Run it advanced and you can break ringlands very fast from detonation.

Yes, that is true, but for different reasons than have anything to do with compression in the engine. This is due to, in the case of an engine running too far advanced, the exhaust valve opening too early during the power stroke (after combustion) and letting some of the power (and heat) escape from the cylinder early, which will also cost you engine performance and create higher exhaust temperatures. On the other side of things, if it is too retarded, the exhaust valve will open too late and the engine will have to work to compress the exhaust gases for a bit until the exhaust valve actually starts to open, which will cause loss of power as well and will stress internal engine components. On the intake side of things as well, if it is retarded the intake valve will open well after the piston has started going down and it won't get a full intake charge and if it is advanced, it will open before the piston reaches TDC on the exhaust stroke and some exhaust gasses may be pushed into the intake manifold and prevent the intake charge from being drawn in properly.

Slippery wrote: Is it in my head or a bunch of people are trying to help you understand your problem and you are brushing them all off. It sounds like you know more than everyone else here ... Not even sure you need our help. Maybe I am incorrect and took it all wrong.

I'm not trying to brush anyone off. However, no offense to anyone, but the Internet is full of well-intentioned people who don't necessarily know what they are talking about. I just want to be sure that the information that is being offered by people is accurate and relevant to the conversation, that's all. So, I wanted to do some more research myself to back up what people have claimed that the cam timing can impact the compression on the engine, and so far it is not making any sense to me. I'm not saying that I am 100% right, but if what is being said is true, I'm just not understanding it and so far no one has been able to explain it to me in a way that makes sense. Plus, I have shared all the information I have researched so other people can read it and verify the information for themselves as well. I am all about learning new things as I know that I don't know everything, but at the same time I don't want to get mixed up and confused with misinformation either. That is why I have to always check and verify anything I'm not 100% sure on or that doesn't seem to make sense to me.

You will find times when certain subjects are above ones capabilities ... This might be one of them ....

If your timing is off, your compression #s are not going to be as high as if it was dead on. Depending on how far off, it will be more ot less. No ifs or buts about it.

In reply to Slippery:

This is true, though generally speaking, if putting a tablespoon of oil down the bore brings compression up from abysmal to acceptable, its bad rings/bore.

Kenny_McCormic wrote: In reply to Slippery: This is true, though generally speaking, if putting a tablespoon of oil down the bore brings compression up from abysmal to acceptable, its bad rings/bore.

I agree.

They probably suffered from running with the timing off for so long.

MalimAn said: I'm sorry, but that doesn't make any sense to me. To quote one of my links about engine timing, "The diagram above illustrates the conventional 4-stroke cycle of an internal combustion engine. It can be seen that both the intake and exhaust valves remain closed during the compression and ignition phases of the cycle. It is therefore usual for any discussion of valve timing to focus on parts 1&4 of the cycle, that is the valve motion in the periods either side of piston Top Dead Center (TDC) on the non-firing stroke."

Your quote illustrates why variances in cam timing are very important. Even with a single camshaft engine, if your cam timing is advanced or retarded far enough, the variation in cam timing will determine if the valves are completely closed or not during the compression and ignition phases of combustion cycle. If the timing is advanced, the exhaust valve will open during the power stroke and rob you of power, if the timing is retarded the intake valve will be open during the compression stroke and you will get lower compression readings. That's why this statement is true

VolvoClearingHouse said: It's a common trick to advance cam timing to pick up a little DCR in an engine and gain low end torque. Ford actually retarded cam timing in the 70's as a smog trick to lose DCR and reduce NoX emissions (leaving a bunch of power and torque on the table in the process). When de-smogging a 70's Ford engine, the cheapest HP/$ is installing a "straight up" timing chain.

If this was my car, I would take ChandlerGTI's offer and throw in a "new" engine. Then tear down the original one and do some forensics to see what happened.

If it were me, I'd take my advice, get what I could back from the shop, pitch the thing and buy a riceburner.

Bro, no offense, and since I know you in person (unlike everyone else here) I know you're just trying to understand what's going on and are pissed about the whole mechanic thing. So let me just leave it at this, you're wrong about valve timing not affecting compression, but we can discuss that some other time, as there's kindof bigger fish to fry here, m'kay?

What we know:

-Compression is Low -A shot of oil brings up compression, according to the 2nd shop

Thus, we can conclude your engine has excessive ring wear. How did this happen? It sounds like you may have to go back to shop #1 to find out. If he tried to ding you for an entire bottom end rebuild...well, you really need proof he did something wrong during the first round a repairs that caused the engine to now need a rebuild.

Ahem.....

http://grassrootsmotorsports.com/forum/200x-classifieds/parting-out-1984-mercedes-190e/92127/page1/#post1639364

Betting that whole car could be had for cheap...might even make the trip home for dismemberment.

Heck, Bro, your car has rust. Transfer the stick shift stuff into this car and it's nicer than what you've got now!

'It leaks oil terribly...' from the frying pan into the fire?

Curmudgeon wrote: 'It leaks oil terribly...' from the frying pan into the fire?

I kind of agree. Yes, the body is nicer than mine, but it sounds like it has the same mechanical problems with the engine that my car did. I do like the spoiler on it though, I always wanted the 16V body kit, but with the AMG front bumper for my car eventually. I think that would look sick. But anyways, I digress...

Still, DEPENDING on if I can get it cheap enough, it might do the trick to get me by through the winter until I can either get my truck finished or my Mercedes back working again. Then I can use some parts form this car to get mine working again or pull the engine and transmission out of my car and put it in this one since the body is cleaner on it. Whatever works...

Of course, I also just found THIS car locally while I was driving around this weekend:

The guy is asking $750 for it on the For Sale sign...

Domestic wagon for the win!!!

Man, for $750 if it runs and drives reasonably I'd buy it.

Check out the wagon and if it isn't in bad shape cut your losses. I know what it's like to pour money into a car and end up in worse shape than you started, but sometimes you have to know when to fold.

DAMN!!! That sucks... I just called the number on the For Sale sign about the wagon and spoke with a woman who told me that someone came by yesterday and offered her $450 for the car, so she sold it and was just waiting for the guy to come by today to pay for it and pick it up. She said he already picked it up this evening. I literally JUST drove past this car (and took some pictures of it) not 4 or 5 hours ago! Oh well... I guess my search continues...

(And I would have offered to pay her at least $500 for the wagon!)

Assuming it runs and drives, that guy STOLE that wagon!!!

Those things go for at least a grand down here in any kind of serviceable condition. And they're a Chevrolet so you can fix them with a hammer with parts you can find lying under a tree.

It doesn't look rusty, either, which is rare in NY.

He who hesitates...