My long term 300E Sleeper Project

buzzboy said:

And those wheels that came on it... ewww.

Yeh, I killed that pretty quick, sold them for pretty much the price of the tires, which were pretty new.

In reply to Kyngfish :

Thanks for the invite. I live in SoCal now, but about to move to Southern Oregon. I was in West Linn for 15 years.

This site for some light EFI reading. I studied this site and all their downloads extensively when I embarked on my first stand alone. I'd also encourage you to look into classes through HP Academy...if you take the EFI class it teaches you the important stuff about calculating some table data that will get your engine started on the first try. All your friends will think you're a genius. 

Mezzanine said:

This site for some light EFI reading. I studied this site and all their downloads extensively when I embarked on my first stand alone. I'd also encourage you to look into classes through HP Academy...if you take the EFI class it teaches you the important stuff about calculating some table data that will get your engine started on the first try. All your friends will think you're a genius. 

Thanks for this, definitely a good resource. Also - found a trigger wheel from a guy at peach parts, more updates to come!

I find myself drawn to these cars lately.  I have visions of rally-crossing one.

I'm very interested to see where you go with your project.

Love me some 124 content.

my current 

they make about the best sub 5k cruiser anywhere.

@chandler love that coupe man, so much late 80s early 90s class.

So a few updates here - over the past few days I've made a few minor changes, even though I am going to go EFI at some point in the next 12 months, while I build that up, I decided to ahead and change the aging injectors and seals in the existing engine. 

Definitely smoothed out idle a little and a little on startup, though I think I have issues with my fuel pressure regulator as it has some issues starting up after sitting for a bit. 

Also - I installed new aftermarket camber arms for the rear wheels, the larger tires were rubbing slightly, so I figured a little extra camber would look a little more boy-racer AND solve my rubbing problem, I also rolled the fenders - using an Eastwood fender roller, a heat gun and some patience.

Last - I went raiding the junkyard and picked up an intake manifold from a similar car - and I figured I'd ask the GRMers here, as I modify the manifold with the intent of switching over from CIS to EFI - is there any advantage on this engine to switch to a larger throttle body? I've noticed that the car doesn't like the revs quite as much as I would like, and wondering if breathing better might help it. 

Obviously I intend to go turbo as part of this journey, but since the first step is EFI + ignition, just wondering how I decide what throttle body size is adequate?

I love me some W124.  Just told Lil Stampie yesterday that he needs to get a good paying job when he's an adult so that he can buy me an AMG Hammer.

this is for you Stampie, we found it in a mobile home park in Indy with 20" chrome wheels lol

In reply to chandler :

I need bigger pants now.

Stampie said:

I love me some W124.  Just told Lil Stampie yesterday that he needs to get a good paying job when he's an adult so that he can buy me an AMG Hammer.

As sexy as that hammer is. A straight six with modern EFI and a turbo might do everything better. 

OK so I guess when I said long term I really meant it. After driving the car around most of the summer last year, I pretty much let it sit all winter. The plan had been to pull the engine over the winter to get it ready for summer but then I bought a trailer cheap that needed a lot of work, so I spent the winter refurbishing that instead since I have a ton of landscaping to do this spring. That said, I finally put the Benz in the garage a few weeks ago to get ready to pull the engine, and I managed to do it without effing up too hard. 

The M103 is just massive in that it's super long, and looks like it belongs on the front of a fighter plane. I only managed to break two things, apparently I forgot to disconnect the speedo cable from the bell housing so I guess I'm buying a new one of those, and I'm pretty sure the linkage to the transmission is bent - so getting a new one of those.

First tasks in order:

1. Gonna remove the head and take it to the machine shop to get cleaned and refurbished. Depending on cost I'll either do part of the job myself or let them do all of it. The engine stand is supposed to support 1/2 ton but when I stuck the engine on it, the stand didn't give me a firm "Yes!" It was more like a whimper. So I want to take some weight off the block.

2. Remove alternator, starter and AC compressor for refurbish/rebuild. Brushes and bearings are cheap, so I might as well. 

3. Measure the bottom end to see if I need to rebuild there.  

Second to last pic there is the transmission fluid. Pretty sure it isn't supposed to look like that. To me that looks like maybe oxidation in the transmission fluid cooler on the radiator? Love some feedback from the knowledgeable folks here to tell me what they think. I have a spare radiator I pulled in the pick n pull so...

Beautiful cars and worth saving.  God bless you for getting rid of those wheels.

Hi, nice work you are doing on that W124. I did a MS2 conversion on my M102 190E. I can help you with your build if you need. 

I would recommend doing spark and fuel at the same time. It's easier to remove all the old sensors off the engine and start over than questioning if every part you remove had some function in the OEM ignition system. Spark isn't that difficult to do once the MS is setup. I used a 36-1 wheel welded behind the crank pulley and used a VR sensor off a Ford Explorer (Standard Motor Products PC250) to read the signal. The ECU drives 4 round type LS coils that I mounted on the valve cover. It even uses the stock LS wires and spark plugs (yay! no more searching for non-resistor plugs). Works flawlessly.

For the transmission, your choice of keeping the 722.3 automatic makes sense and will eliminate a lot of variables. It's stronger than the 717 manuals anyways and it works well.

I find that the regular Mercedes forums have information from 2005 and most likely the users are the same as 2005. If you mention turbo M103 plans on Peach, you'll get this one guy telling you that the 1980's Mosselmann twin turbo kit is the best thing since sliced bread and that all this standalone EFI smoke and mirrors thing is bunk and that the best way to fuel the setup is by using stock CIS with 2 additional injectors under the metering plate, controlled by a splitsecond microcontroller... If you have Facebook, there's one group there called "Benz M103/M104 builds". The information is hard to track on FB, but it seems like the high HP turbo build guys are on that group. And they use real EFI, not 1995 band aid solutions.

Let me know if you have questions. M102 and M103 engines don't actually share much parts, but the "design philosophy" is the same. One guy linked to my build thread on page 1. Maybe you'll find some answers to your questions already 

In reply to Kyngfish :

I might be picking up a 300e with a 5 speed in the next few weeks. If it's rusted to hell I'll probably part it out. Let me know if you're interested in the manual transmission setup.

Rocambolesque said:

Let me know if you have questions. M102 and M103 engines don't actually share much parts, but the "design philosophy" is the same. One guy linked to my build thread on page 1. Maybe you'll find some answers to your questions already 

Hey! Thanks for the offer to help, I've already taken a gander at your excellent thread and do plan on using that as a resource. I already sourced a trigger wheel for the engine from a guy in Australia, the nice thing about it vs. other solutions I saw is that there was no need to remove the harmonic balancer, which I preferred. 

I think my biggest question for MS3X (I found a fully built unit on the Pelican Parts Forum for well under retail) is what sensors I need to keep on the existing ECU vs. what I need to put on MS. Ideally I dont want a constant CEL, so I don't know if I need to send dual O2 signals - one analog and one wide band to the old and new ECU. Other than that I plan on fitting a GM throttle position sensor to the existing TB using an adapter plate I'll probably fab up. I haven't seen a concise description of what sensors need to go where on the M103 and since I'm totally new to this- I may reach out for pointers. I am actually already on the M103 builds group and they've been helpful now and then.

RE: Spark and Fuel, you're probably right, and in the past day or two that's more or less what I decided myself. Turbo is going to have to wait this year, just not in the budget right now and I haven't seen a lot of great intake manifold options. Anyway since this is my first MS experience, I think I want to try to keep it as simple as possible and go from there. 

yupididit said:

In reply to Kyngfish :

I might be picking up a 300e with a 5 speed in the next few weeks. If it's rusted to hell I'll probably part it out. Let me know if you're interested in the manual transmission setup.

Man I would love this car to be manual, but as Rocambolesque pointed out, the manuals in these cars don't tend to be nearly as strong as the auto, and probably better as an auto for this particular car anyway as it's not really going to be my sporty ride. 

In reply to Kyngfish :

That's fair. I have a manual behind the m104 in my 190e and it really wake these i6's up. If there are any parts that you need, let me know. 

In reply to yupididit :

Where are you located?

In reply to Kyngfish :

Northern Virginia. Just outside of DC. 

Question for the crew here, I tore down the engine, and honestly everything looks like it's in good shape exceeeeept. Cylinder 5 has a slight pit and discoloration in the finish - my guess is because it sat for four years, it's sitting slightly above the piston head when the piston is at BDC, so fairly low in the cylinder. It's a really tiny pit. That said, is this something I need to either repair or look for another solution on?

Pics below:

I wouldn't worry about it.

Sendit :)