I have a 2014 c300 4matic, which I love and I've determined I'd like to keep forever. My plan is to swap from my m276 to an M157 (along with upgrading suspension, transmission, exhaust, etc.) once my current engine blows. What I'm unsure about is if the M157 will fit. There have been successful swaps to the m278, which is the same platform, but it displaces less than the AMG M157 engine. Does anyone know if the M157 and M278 are much different in size, and by how much? And before anyone says it. I don't want a c63, I'm pleased with my car and I want to use it as a summer/weekend vehicle once the swap is done. Money won't be a problem for the swap either. Just wondering about the size difference between those two engines, or if anyone knows if it's been done already. Thanks

 

Not sure how many miles are on your engine or how well it was maintained or how old you are, but if you're waiting for it to blow, you may be too old to drive when it happens. Just make sure your engine is not affected by this Service Bulletin or has already been serviced.

 

I have no idea. Maybe look around the W212 threads.

https://mbworld.org/forums/e-class-w...7-engines.html

 

I'm in my mid-20s. My car is fully serviced to this point and I got it just over a year ago at 70,000 miles. It is now at 100,000. I drive a lot to work, and I know the m276 can last anywhere from 250-300k. However I have the opportunity to purchase a 21k mile m157 for a pretty good price right now, so I figured I might be best off buying the engine and waiting.

 

If the price is good, then it may be worth it. But you will also need the ECU to match the engine, as well, for fuel delivery and spark timing. I've not done an engine swap on a modern Mercedes, but I do know that the anti-theft features of these cars require a lot of coding when swapping out major components. At your current mileage rate, you'll be looking at five to seven years before a potential engine failure. By then, who knows if the environmentalists will have convinced the government to outlaw the internal combustion engine.

 

Since it’s basically an M278, the bare engine will probably fit. As you mentioned, you’ll need the whole drive train to handle the power. But M157 has different exhaust manifolds and I don’t know if the engine compartment of the C63 is modified to accommodate. The other 2 things that come to mind are the wiring harness, the C63 has additional transmission controls; and the compatibility of the instrument panel and head unit with the AMG software.

 

Yeah, I'll likely take it in to be mapped to better suit my car, and hope all functions are working properly. You're right, I'll probably be mandated to drive an EQE by the government at that point.

 

I'm hoping that if I can manage to fit the engine, the rest will work as well. I'm awaiting a call back from my buddys dad who is a retired master tech and autoshop owner to see what he thinks.

 

Let us know what he says. Back in the day, before electronic controls, a swap was relatively simple. Now, with everything integrated, it’s gonna be a real pain.

I worked with a shop to do an automatic to manual tranny swap on a 1999 Audi A4 and it was a total nightmare. We got it done, but it wasn’t fun. The engines on automatics used a different crankshaft than manuals and the end had to be modifies to fit the tranny. Plus, new mounting brackets needed to be welded to the chassis.

Good luck!

 

First I will say if money no problem almost anything is possible.

However, per MB specs your C300 is 180.8 inches long. The C63 is 185.3 inches long. That extra 4.5 inches is all in the engine compartment as the engine is longer (2 extra cylinders). So, would need extensive modification to entire front end along with transmission, differential and who knows what else.

For what that all would cost I bet you could save money buying a C63...

 

But he wants a sleeper! I think a C63 with a C250 badge would do the trick. Maybe replace the C63 body kit with something more benign.

 

So he says that the engine should theoretically fit, as well as the MCT-7 tranny, and all mechanical components needed. However, I'll basically need my entire car reprogrammed for it to work the way I want, which will require someone with some serious knowledge to do.

 

The m156 is the c63 engine for the w204 series, which is the naturally aspirated version, and has been tuned up to 520 hp while remaining road-legal. The m157 is the biturbo version, which only has a 5.5L displacement vs. the m156's 6.2L. The m157 has also been tuned up to 715hp while remaining road-legal which is a major selling point for me. However, this engine was never put into the c63, and was used for the S, SL, E, GLE, and G class AMG variants. I'm too attached to my w204 to want to opt for anything else, and imagine 710+ hp c300 4matic.

 

Before forging forward, consider what @GunDriver said about under hood dimensions. I thought the extra length was mainly due to trim components. But maybe not. That might require swapping in a whole front structure from a C63. Quite a big chore on a unibody car. Check the location of the front structure brace/radiator mount on a C63 against what you have in your C300.

 

Here's a thought. Get a M276 M30 (3 liter turbo) and upgrade the turbos with Weistec turbos to produce about 540hp. I've considered doing it with my SL400. At least you know it will fit the engine bay.

Mercedes Benz AMG M276 W.3 Turbo Upgrade C43 E43 | Weistec

 

That was my initial thought as well, however, it will no longer be street-legal. Which is quite discouraging to me. Whereas the m157 plan would be.

 

Maybe a stock M157 would be street-legal, but if you plan to tune it to 700+ hp, you're not going to be street-legal either. You really think the inspection station is not going to notice a 700 hp C300? I don't know how they test where you are, but if a 700 hp M157 will pass inspection, so will a 540 hp M276. The Weistec turbo upgrade uses the stock turbo housing/exhaust manifolds, so visually everything looks "normal" in the engine bay. A V8 in the engine bay of a C300 is NOT normal.

 

Arent there additional coolers/radiators with those larger engines that need to fit? I thought this was the C63 front end is longer, plus the larger engine.

 

I'm thinking to do same with w164, and w204 actually fit m156 which bigger size then m157, so should fit, only question in electric parts like ecu and can's, but by my research about w166 everything should works as is cuz first release was almost same as w164 ml 63

 

https://mbworld.org/forums/c63-amg-w...cessfully.html
that actually was already done