New member looking for first W201

[s_holford]

I figured it was time to join since I've been lurking for awhile. I've been cruising some of the other Mercedes forums but I'm finding much more technical info here.

Well about me, mid 40's, gearhead since I was a teenager, prior service jarhead (helicopter mechanic), now a maintenance manager for the I&E Shop at a chemical plant. I grew up working on 70's & 80's GM G-body cars and that got me started on engine swaps. I currently reside in Illinois but looking to relocate to Nevada or Arizona soon.

Fast forward to now, I currently own a W208 CLK55 AMG which was my first Mercedes as of 2 years ago. I learned the hard way about buying a cheap Mercedes and performed a ton of needed maintenance myself. It's now a daily driver and one of my favorite cars that I've owned regardless of it being 20 years old.

Lately I've had bug to buy a W201 and I've been looking for about a month. I feel the need to tinker so I'm exploring swaps, updated engine management, and modern EFI. I'm looking forward to learning more about these and I have a good idea of what I want to do. I'm really leaning towards a M104.98 swap but I'm keeping options open while I get familiar with this chassis.

[chuddism]

Welcome. There is a lot of technical info here, does require some digging though.
Let us know what you end up with.

[JoeB]

Well if you're relocating to Phoenix, then autohausAZ will be a local source for your OEM parts

If you're wanting to do ANY engine swap into a w201, then your donor car needs to be the 201.029 (190e 2.6) every VIN you scour needs to read WDB2010291xNNNNNN

The reason is simple. The front end sheetmetal is already configured for the 6 cyl engine. The radiator support panels and front end are different to the 4 cyl, the bonnet is also different, latches etc... all different.

This in itself is enough to change the level of difficulty from 'nightmare' to 'bolt in with factory parts'.

So forget about any 4 cyl body IF you are going swapsies.

While the principles are the same from your G body days, the need to have 'expert level' grasp of the EPC and all the 201/124/129 interchangeable parts, wiring diagrams and a clear understanding of the cross-referenced parts.

i.e. do not attempt to do this without having access to the EPC (offline) and WIS/ASRA. You will spend more time cross-referencing part numbers and looking at breaker-yard donor vehicles than you may otherwise imagine.

Finally.
EFI vs CIS-E.
It's a biggie.
Given the choice, I would personally go for an m104.980 over the m104.99x engines.
The 980 may only be 3L but it doesn't have the sensitivities of the later engines, particularly the 'enlarged' versions (prone to head gasket failure on the 3.6 for example)
Also, it's all-alloy intake. no plastic and no variable flap sitting in the bowels of the intake manifold.
Turbocharging is a little easier, but costs $$$$.
As a daily, an m103 3.0 is a very nice thing (extra low-end lb-ft) and low-maintenance. Performance parts are there, and EFI is straightforward.
Obviously not as easy as the 3.2 m104, but there is a need to understand fundamentally that the m104 is a much higher maintenance engine, and things on it need to be done RIGHT, else cash will flow out the door faster than you can say ferrari f1 failures.
Like everything of it's age, understanding that condition is EVERYTHING and mileage is immaterial, consensus will bring you to the realization that whether you like it or not, the entire undercarriage will need replacement bushes from front to back, including engine transmission and differential mounts, centre bearing and mount, tailshaft couplings, 5-link, CV overhaul, wheel bearings(hub) and rear wheel carrier bearing (outboard LCA)

This is something you need to consider at the outset, because the car will inevitably have handling anomalies and incorrect stance due to sagging rubber (or, non-existent rubber)

Why does it need to be considered at the outset?

Parts quality and prices.

Inevitable differences lately due to the absolute junk brand parts that have infiltrated MB markets is a serious problem. For one, they seem cheaper... they will either be ill-fitting, cause damage or simply not last.

Genuine MB parts carry a two year warranty. know that.

Then know your brands.
I cannot stress this enough - avoid Febi rubber, stay away from anything with URO or trucktec on it, Meyle is mediocre at best, and Lemforder is about as good as genuine boxed OE for rubber bits.

Not every brand carries all the bits though, and so you need to do some deep-dive into where the actual parts are made. because the box has Germany on it means sweet F-A.

For example, Febi tailshaft couplings come from the same factory as the genuine MB ones (SGF), and have the little star scrubbed off.... BUT - they also come from a factory in China, and those are seemingly almost identical, but there is no scrubbed off 3-pointed swastika, instead it looks like a normal aftermarket part. In 6 months time, that 'normal' looking part will have almost torn itself, or at least will show signs of cracking in the rubber, whereas a genuine part will easily outlast the 2 year warranty and possibly go at least another 3-5 before scheduled maintenance interval replacement.

that's just one example.

Corteco engine mounts would be another - they are OE and almost twice the price of other brands..... for good reason... they will outlast the others by a factor of 3.

Graf / Laso water pumps.... take your pick. I prefer Graf and koblenschmidt. cast iron impellers, better castings. also made in germany. Laso made in italy very good. stay away from others.

***/INA (schaffler) bearings are OEM. yes, you will find skf and koyo and others... stick with the precision german parts. Nothing wrong with reputable brands, just make sure they are the big brands - timken, skf, koyo and go for a european or japanese manufactured part.

Tools:
You will need some MB-specific tools to make your life easy.
visco fan hub spanner and lock tool
rear wheel carrier bearing removal tool (https://www.sirtools.com/mercedes.htm)
balljoint tool (for LCA - IF you don't want the non-replaceable angled version where you have to buy a new front LCA each time)
spring compressor
Timing chain link tools (mandatory acquisition if you intend to do *any* top-end work yourself)

I would stop there, because there are a lot of mercedes tools that make R&R jobs REALLY easy, but you could spend more than the car is worth to acquire them.
In which case I suggest you find a really good independent specialist who has these tools - and any independent specialist WILL have them if they are good at what they do, because they know and understand the value of proper tool for the job.

Anyone can backyard hack these things, and we all have had to at some stage - but for some things, there are necessary tools that save thousands of dollars, even where the outlay might be as much as 6-700 dollars in tools.

Over time, the tools pay for themselves time and time again. Others will be a one-time and possibly maybe once more.... but the cost of the tool pales into insignificance of the frustration and problems that arise from not having it.

So, like I said, condition is everything.
Service history is a 100% mandatory examination and if the car has no paperwork to support the maintenance claim, assume it has never been done - and if it has, it was likely not done properly... because MB owners are a tight-fisted whiney-ass bunch of whimps that are too scare to break a nail or do an oil change. ANY time their car cost money to fix, you can bet there WILL be a receipt for it, so their whining is congruent with the amount on the invoice.

Since you've been involved in avionics, nearly everything here will not come as a surprise, and you will likely understand the regime of servicing intervals and mandated service items. So you're unlikely to skimp on replacing what is required, when it is due.
That attitude is pretty much in direct contravention with nearly every mercedes owner I come across. The truly capable are few and far between and I count those I know personally over the last couple of decades on ONE hand.

If you are prepared to sit down and examine the factory documentation and become intimate with the EPC, then you will be miles ahead of those who CBF.
The biggest obstacle is finding a good donor, and then purchasing parts with a view to longevity and quality over 'whatever gets it on the road for the least cost'

Because I can tell you hand on heart that when I drive a vehicle, I can tell the difference. Any cursory glance underneath is ready confirmation. Be it exhaust hangar rubbers or aftermarket spring shims. or cheap crap transmission mounts... The differences are very noticeable.

Also just as a quick aside - if a car has a vibration at idle in drive or a knock, don't be surprised to find out that basic things like replacing the transmission mount and gear shift linkage bushes or engine mounts will solve the problem. These are often neglected or replaced with the junk brand parts.... so if a potential donor has a poor manner at idle, having a look underneath will quickly reveal issues like collapsed engine mounts or transmission mounts, centre bearing hangars that are sagging or split, tailshaft couplings that are cracked..... etc.

It doesn't take a huge amount of effort to make these cars feel like new with an intelligent application of mechanical sympathy.

It does cost some money to do it properly the first time. (in a lot of cases you'll likely only need to do it once - per car...)

Beware of Mercedes-rescue-syndrome.
These cars will breed in your driveway if you don't keep a lid on it.

I'm down to six at the moment, and I feel the twinge in the back of my brain from SWMBO every morning when I wake up...

[s_holford]

I would've quoted you Joe, but that was quite a lengthy post. I appreciate the good info though. I've been doing plenty of research on these for the past couple of months and knew a 2.6 model would be my starting point.

I've come across quite of bit of the same issues in parts quality and replacing neglected items on my W208 so I'm well aware of cheap knock-offs. I'm also one of those guys that can drive a car and feel when something is off. Buy once, cry once.

So far I'm not having a lot of luck finding anything nice so I'm trying to be patient. Unfortunately, once older cars become affordable or passed down they're often neglected. Maintenance doesn't bother me as much structural rust, in which I've been finding a lot of rusted out service jacking points since I live in the rust belt.

The EZL failure/cost/availability that I keep reading about is also one of the reasons I'm looking to go with modern engine management. I'd like to go turbo further down the road but I'm thinking I'll take baby steps for now.

[JoeB]

Best advice is to keep it stock until you are familiar with the systems, the vehicle and the service literature.

A lot of people buy one and get in over their head because they thought stuff was easy, and did not plan their "mods" properly.

You will read a lot of their stories here, and like all fora, they come and go, usually when they leave they are beaten and hostile towards the vehicle / brand simply because of their own sheer ignorance.

No different in VAGworld or BMWland either. But the learning curve with Mercedes is a harsh one. Either you get onboard with their factory service manuals and EPC/WIS, or you will pay through the nose and end up throwing money at a problem because beligerance took you there.
The factory service manuals and EPC are very thorough. Yes there are always alternative means to achieve a similar outcome, but the factory way is actually the most efficient in 95% of cases.

Hold off on your purchase and wait for the best condition vehicle you can find for your budget. a W201 is no longer a cheap car to own and service. But it's certainly a better car than the 202 or 203, and if not for the 204's electronics and the c63AMG, I'd almost say the 201 is better than a 204 as well.

Keep looking for that gem. They are out there. Good luck.

[secretmachine]

Check out this thread for a bit of an idea for what's required when doing an m104 swap - https://forums.190rev.net/showthread...ine-swap/page4

[s_holford]

Check out this thread for a bit of an idea for what's required when doing an m104 swap - https://forums.190rev.net/showthread...ine-swap/page4

Thanks for the link. Im kicking around some future ideas of an M104.98 turbo build. I've been digging through build threads trying to figure out what everyone is doing with the rest of the drivetrain so nothing frags at the 300-400hp level. From what I've read these come with the 722.4 correct?

[JoeB]

Trans will be a 722.6, ideally the v8 unit with the 6 cyl diesel (OM612/3) front bellhousing. Sprag clutch will need attention regardless and that will leave a stress free trans for silly bhp.

driveshaft you will have to measure on the front section. I had a custom made thick wall chromoly unit with a modified universal and weldyoke in the centre, to allow factory fitment of centre bearing and hanger. for the rear you will need the w124 6 cyl diff, preferably LSD, and by LSD you will need to look at options like Drexler, OS-Giken, Quaife or Wavetrac - it will depend on how much you want out of your diff and how hard you're going to pound the thing.

You're going to need to overhaul the CV joints on the halfshafts at a minimum, possibly there will be a need for custom 300M shafts in the CV's, but you will be surprised at how strong the MB driveshafts are. When one goes, it's usually the outboard CV at the spline shoulder (fuse).
Have a look at turbobandit and see how minimal the amount of work is required to achieve big hp numbers - you'll be surprised how minimal the work really is, and to top that off, it's relatively low stress and reliable.

[s_holford]

Trans will be a 722.6, ideally the v8 unit with the 6 cyl diesel (OM612/3) front bellhousing. Sprag clutch will need attention regardless and that will leave a stress free trans for silly bhp.

driveshaft you will have to measure on the front section. I had a custom made thick wall chromoly unit with a modified universal and weldyoke in the centre, to allow factory fitment of centre bearing and hanger. for the rear you will need the w124 6 cyl diff, preferably LSD, and by LSD you will need to look at options like Drexler, OS-Giken, Quaife or Wavetrac - it will depend on how much you want out of your diff and how hard you're going to pound the thing.

You're going to need to overhaul the CV joints on the halfshafts at a minimum, possibly there will be a need for custom 300M shafts in the CV's, but you will be surprised at how strong the MB driveshafts are. When one goes, it's usually the outboard CV at the spline shoulder (fuse).
Have a look at turbobandit and see how minimal the amount of work is required to achieve big hp numbers - you'll be surprised how minimal the work really is, and to top that off, it's relatively low stress and reliable.

Good info. Is there a preferred controller for the 722.6? I'm familiar with it otherwise since that's what's in my CLK. I also happen to know where one is out of an R129 SL500. There's someone parting a '93 300E not too far from me either with 119K on it. I may start gathering parts out of convenience!

Since this isn't exactly something that hasn't been done 100 times already, I think it's just a matter of knowing what I need.

[JoeB]

Okay this could be a win-win.
Grab that SL500 trans and Shifter and linkage. It is the trans you want for the additional clutch packs. Keep the front bellhousing and converter... AND get the flexplate if you can, or at least get the part number. You will need this for reference, and you may even need it to bolt-up to the m104. There are some subtleties in the TQ converter mounting depth, which is not worth getting into right now, but the modus operandi with all conversions is "get the complete unit". So that means flexplate to drive yoke, and even propshaft if you can.... and the Diff - or rear subframe... because R129 brakes and diff and driveshafts are king.
Grab his front LCA, hubs, spindles and brakes as well. that's a bolt-in upgrade right there and the best bang for buck you can possibly get. It may be worth offering him a grand or 1500 for the whole car..... depends on what is in the car or if it is wrecked etc.

I want to hit you up on the bolt pattern for my m117 in the R107 and when you grab an OM612 diesel ML270 trans, you will have the front section. I may want the front bellhousing from the SL, so that would

the 93 300E if it is M104.980 is absolutely the pick of the bunch for toughness in the bottom end. for turbo application you can either use low comp pistons or a thicker MLS headgasket, to drop it to 9.0 / 8.5:1

the M104.980 in EU and AUS is a 10.5:1 compression motor aka ECE motor.

Mines N/A and I shaved the head down to get about 12:1 static. It does make a difference on 98RON. And I can still run 100% standard timing and fueling, a little tweak on the EHA gives me all I need.

Beware of the oil filter housing heat exchangers on SOME M104.980 engines. Here in Arsetraya we got a different oil filter housing with a heat exchanger (coolant) which has a bypass thermostat in it. After about 25 years, the steel line that runs from the back of the water pump housing to the heat exchanger and the little rubber hose from the exchanger to the block fatigues, and leaks, which creates a symptom similar to a head gasket failure (loss of coolant) but also can (if not carefully checked) leak coolant into the oil and kill a motor.

Reason for stating this is that all HFM M104's made after this period came with a similar oil filter housing with a BIGGER heat exchanger and it is prone to failure. i.e. it is a poorer design.
If you are turbocharging, I recommend a remote oil filter housing with bypass thermostat to a radiator in the front left wheelarch. This is the same as the R129 and how AMG did it on the w124 as well. You can use the standard M104 housing and run the cooler lines as per factory (efficient and well routed) or you can go aftermarket with AN lines and a decent radiator with fan (setrab) in the front where you can best fit it.
You're going to need to run water to air intercooling, because there is ZERO space in a w201 front end for a big air to air unit. So plumbing in a W/A radiator will require some strategic planning, especially if you want to keep HVAC, which I suggest you do.
Since you're obviously used to working in confined space situations, and understand how aviation do things, the transfer of this methodology is important to ensuring ease of maintenance and reliability in a Mercedes.
In the w201.029 engine bay, you already have stuff-all room with the m103 that's already there. an M104 has "less" room due to the width of the head and the intake manifold. So things are even tighter.
Let me just state at the outset that working in a 201.029 engine bay is NEVER fun. It's a very tight package. Efficiency in design and well-planned execution will be key for you and the longevity of the vehicle.

My advice would be to start as an N/A swap, then get everything working well, and turbo later.

the controller is simple: ofgear.dk. and Ole's been doing this for years and it absolutely IS a plug and play unit, I speak from experience.

You will need a speedo head from a w124 400e/e420/500e and those aren't easy to obtain. but the 201 has a mechanical drive and the 722.6 has no speedo output other than the internal electronic speed sensor, which is fed into Ole's controller. You can piss around with external triggers like I had to with the 716.6, but ultimately you will need an electronic speedo, which you will then need to 'rehouse' in the w201 speedo plastic, to fit into the cluster. Again, not a 100% straightforward process. Using a w126 speedo head may also be possible, but I found the instrument face to be unsuitable for the w124 cluster. (size) so maybe a VDO instrument specialist is required to make it work for you.

You will need to make some adjustments to the rear transmission mount. For the moment, grab the R129 SL500 trans crossmember AND mount. because you will need this to begin with, and you may be surprised how expensive that rubber isolation mount is - about $110USD new. and yes, they DO wear out. It's also different to normal 722.3/4/5 transmissions and not the same as the w140 style.

For now, focus on getting the parts - even if you do not have a donor car yet. It's really important to have access to a "donor vehicle" and you may even find that you need to go back several times for "little things" like bolts brackets and other silly little trinket items.

for an m104 into a w201, I Absolutely recommend you obtain the w124 VEHICLE complete as a donor for the engine.. It will supply nearly everything you need... except the transmission, which you might also consider the entire R129 for pillaging the drivetrain and front end and rear subframe - you won't need the engine, but could sell it and make your money back on the donor. Same with the 6 cyl transmission... and part out the doors etc then send the shell to the crusher.

Remember, stuff like switchgear in these vehicles is getting expensive, so you will want to pillage everything electrical - connectors, harness(complete if you can) and the R129 SHIFTER and linkage from the SL will be necessary, else you will need to go buying on stealbay... Again, Ole's documented all of this in his 722.6 controller manual.

Having been through this, knowing full-well what you are facing, You are going to need some storage space, and the w201 donor might just be the least of your worries.
But, forward thinking and careful planning....
Ideally:
R129 drivetrain - front suspension/spindles/brakes/LCA's - bolt-in.
R129 rear end hub carriers and brakes - definitely. Diff if you can grab it, along with driveshafts. Be aware of the size of the diff and how it mounts differently to W124 and w201, but the subframe itself is a good guide. observation will lead you to understanding here.
the 722.6 from the 129 - and propshaft if you can grab it. Along with the shifter and the linkage.
w124 - donor engine, all the ancillaries that connect to it - whether that is the entire CIS-E harness with it's MAS, or if it is HFM you are going to need a lot of the engine bay wiring. HFM will almost mandate you move to a standalone EFI setup, which will inevitably cost about the same as the donor parts, or more....
There will be a need for an improved radiator, some careful assessment of the fan shroud - which may mean "different"
There will be a need for a STANDALONE transmission radiator AND oil cooler. Do not use the heat exchanger in the radiator header tanks. the Manual 201.029 doesn't have the heat exchanger in the end tank, so that is the part you want to start with for a straightforward swap - which again is where I recommend you start, before going twin turbskies.

Suspension tweaks are simple. H&R coils and B8 Bilsteins for the road - or better yet, grab genuine sportline coils from mbpartsworld and bilstein b8's from pelican/tunersports.com etc. shop around for prices because they are quite different. You will be surprised how cheap genuine parts are in a lot of cases.

So begin with the EPC, get down and dirty and learn your part numbers, how it is all crossreferenced between models and then go from there.

It IS relatively straightforward. Nearly every swap or conversion I have been involved with has been drastically simplified by referring to the EPC and crossreferencing other model Mercedes, and literally finding parts that enable either a direct bolt-in solution, or one with absolutely minimal fabrication and a "factory fit" look.

m117.958 into w123? yep. Like it was meant to be there.
m119.960 into 124.051? yes, because they never existed in RHD. want to laugh? R129 front crossmember literally is a direct swap into the chassis rails. unpick the welds... new xmember in.... et voila.
False firewall required a bit of massage though, since everything is on opposite sides. Battery to boot was a better solution in the end.
Most transmission swaps are simply a case of working out the correct combination of flywheel/PP/CLutch and input shaft length. with Autos, it's the crankshaft spacer to the flexplate and the TQ converter depth, to ensure correct starter engagement and TQ front seal and pump engagement depth are correct.
Tailshafts are normally a bolt in substitute front section, and carefully assembled noting alignment marks. Occasionally a front shaft needs to be extended, as factory did not manufacture one long enough.
Sometimes the transmission yoke needs to be changed. There may be a need to fabricate a spacer to ensure correct bearing pressure, or make a new one from two different yokes. (splines and depth are critical)

The point I am making is that regardless of your "choices" you have a wide range of available bolt-in parts which can solve your issues and they normally come from the vehicle you are sourcing the donor parts. i.e. w124/r129 in this case.
It is normal practice here to keep those "donor cars" next to the project until the project is complete and the last bolt tightened. That way you know you have everything squared away and all the parts you need, plus in many cases quite a decent haul of low-cost spare parts.

So that's the "long-winded" version.

Careful planning and selection of your choice of engine/box/diff/brakes/suspension is up to you.
then EPC to work out which ones will be best suited for your application.

[s_holford]

I really appreciate all of the feedback. This is exactly the info that I need. That R129 was just a trans and I have a feeling the owner is lying about the mileage, however I'm finding the 722.626 to be common in local wrecking yards. I scour FB marketplace, local U-pull-it's and CL regularly so something is bound to pop up.

As for the W124, it has the 104.99 so I'm going to pass. I did find a nice 3.0 M103 the I can pick up fairly cheap, but the allure of the M104.98's higher redline is what I'm drawn to. I know there's a torque trade-off, but I want something that can rev this time around.

[secretmachine]

722.6's are common in the round bell pattern for m111/2/3 motors, the 722.6 with the m10x/om60x pattern is not very common at all, it came with limited models during the late 90's into 00's. Additionally, any m104 can take the 980's double valve springs and unlock the rest of its revs, except the 3.6 amg, which has a terrible rod ratio and is pretty much limited to stock config.

[JoeB]

The 3.6 is not an engine I would even bother with, TBH.
Yes, great if you want the "AMG" in your non-AMG Mercedes.
Other than that, beyond the rod/stroke issue, the bore issue is far too tenuous a relationship for the headgasket to maintain a civil partnership.

104.99x is a problem for twin turbskies due to plastic intake (toss and fab custom alloy???) and while the extra 200cc makes for a torquey NA motor, it is a bit of an internal-cost-cutting exercise when you look in the guts. The finish on the inside is certainly not MB's finest hour and I've seen a few of them. Pistons are a bit on the weak side for high rpm also, and that is why the valvesprings are also a little weak. The motor was simply not designed to take that extra rpm that the 3.0 can.

Also, the squeeze ratio on the 3.0 is almost a perfect one for turbo. combined with the cam advance it really makes a difference - but a 3.0 m103 is no slouch when tuned.

For shits n giggles the OP could also go OM606.962/722.6 and HX35 and ole's controller and Gorans 7.5mm IP and boom. 500bhp diesel 190e. and low smoke.... Baldur's DSL1 and Ole's 722.6 would make it a tuneable diesel on the EDC pump with 7.5mm elements and possible VNT or a quickspool valve. lots of options. not all expensive or requiring 5 billion square acres of parts cars to achieve nirvana.

Get a 606and trans out of canuckistan or the UK from a 98 w210 E300TD and there's even less to worry about.

The thing with conversions are all the bits you need to replace out of necessity simply due to "unknown" factor - water pumps, thermostats and housings, fan clutch, usually tensioner and damper etc at a minimum.
little stuff like that - engine mounts. maybe power steering hoses. trans mount and crossmember... all those things add up to an expensive conversion.

This month, I've topped 4KUSD in parts for a w124.090 and haven't even got the "important stuff" yet.
convert that to aus pesos and yeah.... could buy a frickin car for that kind of coin.

Keeping a lid on spend is always a big issue. If we start talking about maintaining a 16v..... yeah let's not go there.

[secretmachine]

The plastic tri-y intake will hold more bars than one would assume ;p and sure, there are 99x's to avoid and 99x's to go for, namely I like the last version in the w210, 104997 (no egr, better componentry, bio harness corrected, all the 104's revisions). I'm not sure what you mean by the finish, every 104 motor I've had open still had flashing on the crank windows (where it doesnt matter anyway), and the cranks are all 603 diesel cranks, not much to go wrong there. Where all 104's are problematic is the weak un-girdled bottom. All of them lack the external webbing to make that area stronger, so it is very important to add a girdle if you want big power or to take a 980 or 2.8 94x reliably to 10k rpm. Another weak area, other than the beehive springs, is the rod hardware. The rods themselves will take 500hp of boost before needing to be changed out for I or H beam rods. If you want that 10k rpm, you'd need replace the rods on any version with the pauter rods. The pistons, while not being forged like 16v's, are not actually weak, and can take 1200hp, proven by Roman. Any 99x with the piston squirters would be a great motor to turbo due to the extra cooling, and the 99x's with the lower compression makes it an even better choice. The 980 to me, seems like the best motor to make an n/a screamer with, other than a 2.8 94x, the high compression also means there is more open-engine internal work to do compared to 99x if you desire to go the boost route. I would also highly recommend against using a thicker headgasket on a 104.980 in order to drop the compression, in this case you are fucking with your timing chain length, not advisable if you don't have adjustable cam gears. Boost on a 980 is best accomplished with shorter rods or to forever dedicate yourself to running e85 and never let a drop of pump gas get in the tank.

Another tip on top of Joe's about accessory refreshing, buy yourself a new oil pump and oil filter house (or at the very least a new oil pressure return spring for the house). The oil pump failure while building Macarthur101's m104 taught a valuable lesson!

[s_holford]

So maybe you guys can help me clarify something. I'm finding some conflicting info about the M104.98 and chassis availability. I came across a '92 300SE that I haven't seen in person, but vin says 3.2 MPI. I'm also under the impression that the M104.99 had the plastic intake and was 3.2.

I've gotten info from different sources saying the .98 came in some early S-class, others say it wasn't. Which engine is this?

[secretmachine]

You will only find 980's in w124's, and the 981 in r129's. Early w140's had m104.990's, they used what's called LH-SFI (all alu intake). Intakes are not interchangeable to other 99x 104's. They are 10:1 compression making 228hp. Later w140's had 104.994's, which used HFM-SFI with the tri-Y variable intake (aka plastic intake). These are also 10:1 compression but making 217hp.


I personally would not go after an m104 if it was used in a big heavy car like the w140, unless you intend to fully rebuild. Heavier car, more load, more work, over its life.


This PDF will help you to determine which one you'd like to go after and which cars you can find them in. Keep in mind though, we did not get some of the cars listed in the doc.
m104 variations.pdf

[s_holford]

You will only find 980's in w124's, and the 981 in r129's. Early w140's had m104.990's, they used what's called LH-SFI (all alu intake). Intakes are not interchangeable to other 99x 104's. They are 10:1 compression making 228hp. Later w140's had 104.994's, which used HFM-SFI with the tri-Y variable intake (aka plastic intake). These are also 10:1 compression but making 217hp.


I personally would not go after an m104 if it was used in a big heavy car like the w140, unless you intend to fully rebuild. Heavier car, more load, more work, over its life.


This PDF will help you to determine which one you'd like to go after and which cars you can find them in. Keep in mind though, we did not get some of the cars listed in the doc.
m104 variations.pdf

Thanks for the reply. I actually found this earlier and its basically the same info you provided. https://australiancar.reviews/mercedesbenz_M104.php

That pic is from an auction car that's still awaiting the salvage title. It had a good Carfax history prior to the roof and quarter damage.

I'm still trying to locate a 980 but they don't seem as plentiful anymore. As much as I'd like to find an entire parts car I may fare better trying to locate an engine.

[s_holford]

Are there any other pro's/cons to the M104.990? It seems like it's the oddball transitional engine. I ended up winning the auction for that W140 at the ridiculously low price before fees, so even if it's something that sits on an engine stand for awhile I'm ok with that. The car has a good low mileage drivetrain, but had the rear corner of the roof smashed. The plan is to take anything usable and part out the rest. If this particular engine wasn't a good choice I can always sell it. The long term plan is a turbo with stand alone engine management (obviously).

[secretmachine]

The 990 as it is, you'll have a simpler go at efi, and it's got the 10:1 comp. The mid-range will be a bit lacking without that resonance intake of the later version, but its high rpm will scoot in the light w201 chassis.

[s_holford]

The auction W140 showed up today....without a battery in it! I put a battery in it and it fired right up and idled smooth. It looks like it was a nice car before the roof was smashed. All the fluids looked good and the engine looked clean through the valve cover. I should be able to make my money back pretty easily in parts.