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New member getting ready to swap the motor.

523 Views 23 Replies 10 Participants Last post by  Dave2302
Hi everyone! I recently purchased a 2003 SLK230 with an engine that overheated and blew the head gasket. I have another SLK230 motor to install.

A couple of questions. Is there anything I should watch when removing the motor for the swap? Should I pull the engine and transmission complete as a unit? I have replaced dozens of motors on dozens of cars in the past. Just looking for anything unique for the SLK230.

I plan on rebuilding (refresh)

the original motor while running the other motor. Is there anything I should be aware of? 107k miles on the car and motor.

And finally, has anyone replaced an oem motor with a different motor from another car? I have an idea and want to know if the Mercedes Engine ECU is independent from the rest of the car body functions. I think I found a suitable non Mercedes performance motor with a stand-alone ecu and am just wondering how much of the engine controls affect other parts of the car? Or are these completely separate electrically?

Physically, this motor is similar dimensions and mounting, but is a modern dependable 330hp, 420lb-ft motor from a 3600# vehicle.

Thanks for any advice.

Tim
Queen Creek, AZ
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Are you swapping a facelift motor into a facelift model, or a pre-facelift motor in a pre-facelift model?

If so, it should be a direct swap. The transmission on this car sits pretty far forward with the bell housing just in front of the firewall, so pulling the engine and transmission as one unit might be the easiest solution. The transmission is pretty skinny past the bell housing.

While I have experience pulling engines in front-engine rear-wheel-drive cars, it’s for the best that people more familiar with the R170 chime in.

If you are swapping a facelift motor into a pre-facelift or vice versa, I’m not sure about any differences in sensors.
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Both motors are M111.983, so no difference.
Are you swapping a facelift motor into a facelift model, or a pre-facelift motor in a pre-facelift model?

If so, it should be a direct swap. The transmission on this car sits pretty far forward with the bell housing just in front of the firewall, so pulling the engine and transmission as one unit might be the easiest solution. The transmission is pretty skinny past the bell housing.

While I have experience pulling engines in front-engine rear-wheel-drive cars, it’s for the best that people more familiar with the R170 chime in.

If you are swapping a facelift motor into a pre-facelift or vice versa, I’m not sure about any differences in sensors.
If you are swapping a facelift motor into a pre-facelift or vice versa, I’m not sure about any differences in sensors.
Both motors are M111.983
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OP, you should search Dave2302 posts and read about engine ECU firmwares, updates etc.
Different engine in MB cars, with so complicated computer systems...I will just share opinion, if you ask the question, might be having too big of a spoon for your mouth ( without trying to insult or laugh or...) People's problems around here are based on Factory fitted electronics being or getting stupid. Re-educating these electronics might be too complexed task for many.
Ant probably @Alex.M-oneeleven can share his battles with ECU and engines too.
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How to ruin the car !!
Fit any form of aftermarket Engine management ................
Screws up proper functioning of Transmission, Dash Cluster, ABS / ESP, Cruise / LIM.

Motor ECU has to speak the same language as all the rest of the Computers on the Powertrain CAN.
This means that realistically, the only Engine swap that can be made to work has to be a Mercedes Engine from the same era, and even then it's not as easy as some other MB Swaps.

R170 is unique electronically and wiring speaking as it uses Modules and components from different generations of Mercedes, with factory custom firmware / software and oddball wiring for some systems ;)
So lets just say you had a 320 V6 W203 C Class and a 5.4 litre V8 W220 S Class, swap the Motor, Motor Harness and a few other bits, relatively easy, with SDS and KTag needed to virgin and initial start the motor ECU. Job done.

Now try the same M113 V8 swap on an R170 ...................

A world of pain that very few have achieved on their own, hell I'm considered an expert by some, and my core business is repairing MB's, but despite my conversion starting up first turn of the key, and driving with everything working, even I still needed some extremely specialised help on a issue with the Motor ECU Eeprom programming.

Upside is if you successfully do it you have an almost unique Car, I did, I do ;)

If you are wanting to fit another Engine from a different manufacturer, such as any of the plethora of Chevy V8's, Lexus motor, or what ever, I've followed lots of these and they almost always end up scrapped, those that do drive certainly don't work that well as a road car, and definitely not "the goal" which should be that it should look feel and drive as if it came from the MB Factory just one helluva lot quicker, i.e. Supercar quick with handling and braking to match.

That said, don't let me put you off, but please post detailed reports of your project progress here in the R170 performance mods section for all to follow.

I'll leave you with this for a bit of an enthusiasm boost ....





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OP, you should search Dave2302 posts and read about endine ECU firmwares, updates etc.
Different engine in MB cars, with so complicated computer systems...I will just share opinion, if you ask the question, might be too big if a spoon for your mouth ( without trying to insult or laugh or...) People's problems around here are based on Factory fitted electronics being or getting stupid. Re-educating these electronics might be too complexed task for many.
Ant probably @Alex.M-oneeleven can share his battles with ECU and engines too.
How to ruin the car !!

Fit any form of aftermarket Engine management ................

Screws up proper functioning of Transmission, Dash Cluster, ABS / ESP, Cruise / LIM.

Motor ECU has to speak the same language as all the rest of the Computers on the Powertrain CAN.

R170 is unique electronically and wiring speaking as it uses Modules and components from different generations of Mercedes, with factory custom firmware / software ;)
So lets just say you had a 320 V6 W203 C Class and a 5.4 litre V8 W220 S Class, swap the Motor, Motor Harness and a few other bits, relatively easy, with SDS and KTag needed to virgin and initial start the motor ECU. Job done.

Now try the same M113 V8 swap on an R170 ...................

A world of pain that very few have achieved on their own, hell I'm considered an expert by some, and my core business is repairing MB's, but despite my conversion starting up first turn of the key, and driving with everything working, even I still needed some extremely specialised help on a issue with the Motor ECU Eeprom programming.

Upside is if you successfully do it you have an almost unique Car, I did, I do ;)

If you are wanting to fit another Engine from a different manufacturer, such as any of the plethora of Chevy V8's, Lexus motor, or what ever, I've floowed lots of these and they almost always end up scrapped, those that do drive certainly don't work that well as a road car, and definitely not "the goal" which should be that it should look feel and drive as if it came from the MB Factory just one helluva lot quicker, i.e. Supercar quick with handling and braking to match.

That said, don't let me put you off, but please post detailed reports of your project progress here in the R170 performance mods section for all to follow.

I'll leave you with this for a bit of an enthusiasm boost ....

View attachment 628573

View attachment 628574

I guess that I was not clear enough. I am talking about replacing the engine and transmission with a turnkey stand alone independent engine and transmission system without integrating it with the existing ECU or trying to piggy back off of the Mercedes ECU or TCU.
What I am looking for is those items that may take data from the factory ECU to use as an input for a non-drivetrain system and how extensive it is.

For example, is there an ABS input coming directly from the ECU to the ABS computer for calculations to function properly? Or is the ABS system completely independent where the wheel sensor goes directly to the ABS computer? If the ABS system (and most other systems) run completely independent, then there is no issues with a swap.

I do understand that the standard tach, speedometer, cruise, etc. will need dealt with, but beyond that, what
other systems communicate with the drivetrain computers? This isn’t about retaining all the creature comforts as much as making a “kit car” type platform out of an SLK for this drivetrain. My original thought is to use a TVR 280i or a Conquest TSI/Starion ESI-r platform for this purpose but after comparing the Mercedes and donor motors side by side, they are very close to the same physical dimensions.
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Within your welcome post, you have probably got few links 2 much to read all.

I will share few that are going to clear some of your questions SLK Home Page
ABS, roof, gearbox control modules... CAN communication was mentioned by Dave already.

Selecting engine and reading the info tab with this guidance Wiring Diagrams for SLK230
Will clarify the complexity I mentioned.

Yes you can fit engine and gearbox, but they will not communicate with the rest of the systems, that being safely - airbags, traction control...
In my vehicle the ABS sensor signals are going to ASR computer that controls the ABS assembly. ASR has a CAN line to other module(s) and I can't say about yours (links above can).
And another thing, I get the box car, but are you going to be able to make it road legal or not? Because the IC will probably be lit as Christmas Three and that is a sure way to fail safety checks
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I guess that I was not clear enough.
Oh you were !!
Sure you'll get a running engine and transmission, what you are going to do with the rest of the Electronics on the Car .............

Nothing on these cars is fully independent.
Hence my reason for using a Mercedes M113 V8, can get way more power outta one of them reliably than 330BHP.

Good luck ;)
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Perhaps I’m naive, but I really don’t feel like this car as that bad of a black box. I feel like we’re acting like this car is some sort of magic box that is completely impossible to work on.

If all the sensors are the same and you have the proper tools to relearn, what’s the big deal?

This car is just a car like any other car, with systems of similar complexity as other cars of the era. Swapping an engine is no small job, but as long as you have a direct replacement engine with the same sensors and actuators on board there is no reason you can’t get the engine learnt in again.

I happily stand corrected if I’m actually dead wrong here, but in that case I would like to see some examples of why this job is near impossible.
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It's not impossible, but ....

If you are wanting to fit another Engine from a different manufacturer, such as any of the plethora of Chevy V8's, Lexus motor, or what ever, I've followed lots of these and they almost always end up scrapped, those that do drive certainly don't work that well as a road car, and definitely not "the goal" which should be that it should look feel and drive as if it came from the MB Factory just one helluva lot quicker, i.e. Supercar quick with handling and braking to match.
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Not an expert but read their posts with interest.

Can it be done? Probably.
Will there be issues? Definitely.

Read up the pro threads where they simplified ly used another MB engine sourced from the SLK family.
Programming electronics tends to be a stumbling block and need expert help.
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This is gonna be a very interesting project. Pleas keep us advise. I know over on crossfireforum.org some have swapped v-8 in. Have fun.
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Yup, there is more USA Crossfires with M113 V8 than R170's, and even (that I know of) a handful of M113K V8 Crossfires which are in USA and Australia (y)

Still not that many on a global scale ;)

2 or 3 LHD R170's done by Osterle in Germany, but very unique in UK :D LHD is easier than RHD due to the Starter vs Steering Box issue, which involves "manually" boring the Starter location into the Cyl Block on the left hand side, and that has to be done with extreme precision to get the Starter Pinion alignment spot on ;)
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I feel kinda qualified to answer these kind of questions since I have built probably 20 + absolutely mental project vehicles (as well as several insanely powerful Powerboats, one of which had twin 500ci Big Blocks in it), over my 47 years in the Motor trade which also includes owning and driving various exotica too (y)

I feel like we’re acting like this car is some sort of magic box that is completely impossible to work on.

If all the sensors are the same and you have the proper tools to relearn, what’s the big deal?
It is not impossible, no swaps are truly impossible, impractical maybe, i.e. John Dodd, an old Transmission Firm buddy of mine, he built a "Rolls Royce" with a V12 Merlin Engine and drove it on the UK (and abroad) roads. He got sued by Rolls Royce for using their Grille and Baging :ROFLMAO: Impractical, yes, amazing feat of engineering ABSOLUTELY !! ;)

V8's into R170 and Crossfires there are a fair few of us that have done it, fewer who have really got it 100% right, but it is beyond the realms of most DIY'ers and Hot Rodders to reverse engineer Mercedes programming code.

Sensors are not all the same, nor is some of the Hardware and SMD's within seemingly identical modules. Wiring circuitry is also different to the MB norm in certain critical areas, than on many other of it's same era Models, that is the failure points !!
Most who attempt these conversions do not have the correct (expensive) equipment , software and most importantly knowledge to be manipulating and re writing hex code to various Modules !!

Hence there are 100 times the number of abandoned R170 (non standard) Engine swaps, than there are successes.


Almost anyone can cobble together some often awful parts to bung a V8 or whatever into any Car, but the end result is usually something unreliable, not really daily drive-able and often downright dangerous ;)

Several of my previous conversions have been extremely quick, but despite being road legal, they were not a pleasure to drive long term on the road ...................

2 that spring to mind ....

A fun build based on a good mates "that can't be done bet" for £5, and built mainly for a Street Legal Drag Race series !!
A 1972 Fiat 500, 400ci Small Block Chevy with Nitrous, 700R4 Trans, Space-frame, LSD etc etc yak yak yak ......................

Great fun good on the strip, but even a 20 mile road trip on a sunny day was more than enough, despite the fact that the fun there was in cruising along a motorway at 70mph watching for a BMW yak yak yak to come flying towards my rear end, only for me to floor the throttle and leave him in a cloud of smoke and following 2 big black rubber stripes along the carriageway :ROFLMAO:

And then there was the 1999 1.7 litre front wheel drive Ford Puma, (based upon the Ford Fiesta monocoque), another "that can't be done" car primarily built for Special Stage Rallying on gravel forest tracks.
24 Valve Quad cammer 3.0 V6 Cosworth (formula 3000 Engine developed originally by Brian Hart, who sold out to Cosworth), mated to 5MT 4x4 Cosworth Sierra running gear, brakes, steering etc etc yak yak yak ;)

Extensively modified floorpan and monocoque, wide arch Ford Racing Puma body kit, and full Stage Rally spec ................
Absolute beast in the forests and on tarmac, but rearranged your innards and spine plus deafened you when driving on the roads for much more than a 25 mile round trip !!

The Fiat 500 ....







The Ford Puma ....







On the other hand three of my previous monster engined Cars shown below were built purely for road use, very street-able, everything worked and interacted exactly as it should and 2 capable of sustained 170 mph +++ the Firebird was clocked at over 200 mph and ran high 9's / low 10's, even the Range Rover, which is as aerodynamic as a brick would get just over 150 mph with it's 6.5 litre Turbo Diesel Chevy V8 and 700R4 Chevy Blazer Transmission, that Range Rover was built to haul my Powerboats back in the day, and haul ass it did ....







Not forgetting the current supercar on my fleet which has hit 176 so far before my 'arris told me it was time to brake hard before I ran outta tarmac 🤣 ....



Hope y'all enjoyed ;)
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That’s what I was trying to say, but much better coming from those that do and not me that watches.

ps
Dave

Is there somewhere we can launch a modified reliant robin…other than into a loch.
Asking for a friend whose farming project has hit a bump.
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RIP John Dodd :cry:

C'mere there's more ..................
I knew I'd find some linkys somewhere, these will show ya's that didn't know him what an absolute character John Dodd was ....




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Only watch the 2nd thus far.

A grin car, a respectful vid.
Guy was pure genius.

Now, I may be showing ignorance, but if being used then I suspect power steering might be a pita. I’ve hit those wobble pot holes and stones that deflect steering and it’d be the last thing I’d want on an autobahn. As is would it not just sail thru such?
Sure, a 20 zone would be titanic but….

Now, just imagine if the British car industry had engaged with him….

5 x 5.4 = 27!

cold shower time.
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The ideal engine swap would be to take the car to where Mercedes left off, or should have taken the platform. And as Dave has commented, it should have factory fit and finish, to be a reliable vehicle fit for trips or daily use. Like Jay Leno would do on a restomod for example.

I have lived with 5 R170 SLK's, over 11 years, and know them well.
There is a path to modern greatness for the SLK230 if someone with the resources wants to try.

Build an SLK45 AMG.

M139 416hp 4 cylinder AMG engine and trans from the A/GLA45.
Put the car on a diet, carve off a few hundred pounds with lightweight seats, carbon hood, trunk lid, etc. (R170 already lighter than newer SLK models)
Use the SLK32 AMG suspension parts, shocks, springs, sway bars. (AMG tuned, best compromise of ride and handling, why try to reinvent)
Carbon fiber chassis stiffening at strategic points.
Remove unsprung weight with forged aluminum or magnesium wheels (Augment in Canada will custom make any wheel for a price that isn't crazy) and lighter brake calipers on front .
Wavetrac diff.
Get all the creature comforts and instrumentation working like factory.
The result would be pure modern motoring joy in classic form.

Dave's interpretation of the SLK evolution is equally great in a different way, with period correct MB V8 and quality that looks like factory. Just, awesome.

There is a company in the US that puts E55 supercharged V8s (500+hp) into the SLK/crossfire chassis in a quality way, if the v8 path is your thing, use them or their template. Want to Wake Up a Sleepy Crossfire? Drop in a Supercharged AMG V8! (motortrend.com)

If you are going to do it, do it right,.
Happy top down spirited motoring.
R
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Loving this topic 🤪 🤪 🤪
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