Engine/transmission swap recommendations

[GazEddy]

Hi all,

I recently managed to pick up a 1985 SEC 500 AMG for a bargain price. It's been sat for 10+ years, original engine is high mileage and an impractical lump these days.
Instead of going the repair/straight swap route I'm wanting to swap in something newer/more powerful and economic if possible.

Has anyone performed a swap like this, and have any advice/recommendations? As it's automatic, I want a manual swap too. A friend has recommended a turbo k-series from a Honda due to cost and weight and ease of sourcing one, but this would surely involve a lot more custom fabrication to make it work.
I'm open to any advice/recommendations. Thank you

 

[ray_hennig]

lot more custom fabrication to make it work.

I'm no expert but, from reading many forums, the project you're planning is inherently complicated and costly. But possible.

I'm sure that a modern Mercedes V8 plus a manual gearbox and all that goes with it would be stunning. Or what about the 600 V12? I've seen those in a W201 and W124.

So, an interesting project but prepare yourself for serious, 5 (?) figure investment.

RayH

 

[Petrol Pete]

Hello and welcome . a N/A M113 V8 would probably drop right in . Quite a few used ones for sale out there. Chasing economy is going to be expensive IMHO.

Go on YouTube and find Anderzén , he is (by his own admission) just a young bloke working out of (what appears) to be his dad's garage and trying stuff out on various old MB cars.

He put a manual transmission in a C55 (M113 V8)

 

[grimupnorth]

I'd check out what's been done in the states. GM LS engines are very popular swaps in loads of cars over there. This link starts with a R107, but moves on to others. I suppose it comes down to money, ability and time.

Engine swap options for the R107

www.benzworld.org

Or closer to home Dyno Torque in Birmingham

Dyno torque

 

[Martyn_n]

Just out of interest, what makes it an "AMG" car? If it is fully fettled by AMG at the time of delivery I would have thought it would make it a pretty special car and any changes to it (putting a Jap engine in) would devalue it far more than you'll benefit by improving the fuel economy. If it just has an AMG badge on please ignore my post!

 

[Petrol Pete]

Asking 'what makes it an AMG car ?' on here usually opens a oil drum of worms. I see my own AMG as 'pretty close' It's a petrol V8 built in Germany with a hand assembled motor.

Purist might argue that the last true AMG was built the day before AMG sold it's last shares to Daimler Benz. One thing is for sure MB (just like all the others) have diluted the 'AMG brand' to the point of almost being pointless to all but the people who 'know' what a real AMG is.

Mercedes-AMG - Wikipedia

en.wikipedia.org

 

[BaldGuy]

@jaymanek @ Mercland is the man to speak with.... His personal collection of Mercedes includes many conversions all done better than new and with incredible attention to detail....

 

[Bellow]

If you are considering a transplant, the first thing you need to get on top of is the final drive ratio. It seems that for V8 SECs 3.07: 1 is a low ratio and that a numerically lower (but 'higher') FD is likely. Not surprising as AFAIK the 4sp auto box has a direct drive (not over-driven) 4th gear. Any manual box you intend using will inevitably have over-driven upper ratios and with a smaller engine will be unusable. The lower ratios with a high diff will also be high and 'gappy'.
Unless you intend using the car for high(ish) speed M-way, A-road cruising (and get appropriate) gearing you may find no economy benefit from a smaller engine as it will be working so hard it will probably be running rich (self preservation) a lot of the time and a turbo motor will likely respond best to high octane (read - expensive) fuel.

If this car was mine I'd be considering refreshing its own engine and converting it to LPG (a single point system could be put together for under £1k, compatible - I think - with the standard KE Jetronic system). My 260hp 2-2.5 ton truck on LPG is returning the fiscal equivalent of 35mpg. By comparison, a transplant - any transplant - will be a carnival of pain.

 

[Martyn_n]

Asking 'what makes it an AMG car ?' on here usually opens a oil drum of worms. I see my own AMG as 'pretty close' It's a petrol V8 built in Germany with a hand assembled motor.

Purist might argue that the last true AMG was built the day before AMG sold it's last shares to Daimler Benz. One thing is for sure MB (just like all the others) have diluted the 'AMG brand' to the point of almost being pointless to all but the people who 'know' what a real AMG is.

Mercedes-AMG - Wikipedia

en.wikipedia.org

I would agree with everything you say.

I specifically asked about what made this particular car an AMG because it predates the dilution of the AMG brand (It's from an era when AMG was a brand, not just a trim level) Therefore, in order for it to be called an SEC 500 AMG (not AMG Line!) it should have some special tweaks, performance and / or cosmetic, that makes it stand out from a contemporary cars that didn't pass though Affalterbach. I was just interested as if it does have some AMG provenance any engine change would be detrimental to it's value which, for me would help with making a decision on how to progress.

 

[Bobby Dazzler]

How about dropping the 560 engine in? It ought to be a relatively straight forward job as the SEC came from the factory with the option of a 560 engine.

 

[tonysmb]

Just out of interest, what makes it an "AMG" car? If it is fully fettled by AMG at the time of delivery I would have thought it would make it a pretty special car and any changes to it (putting a Jap engine in) would devalue it far more than you'll benefit by improving the fuel economy. If it just has an AMG badge on please ignore my post!

If it was a 'genuine' AMG there were mechanical and body changes: lowered suspension, new dampers, bigger wheels/tyres, camshaft changes, head work, a body kit (spoilers fr & rear, sills and, IIRC, a different steering wheel.

I can't recall whether you could order just the styling kit as a stand-alone option but I might be confusing that with other similar looking body kits that were available at the same time.

 

[Bobby Dazzler]

If it was a 'genuine' AMG there were mechanical and body changes: lowered suspension, new dampers, bigger wheels/tyres, camshaft changes, head work, a body kit (spoilers fr & rear, sills and, IIRC, a different steering wheel.

I can't recall whether you could order just the styling kit as a stand-alone option but I might be confusing that with other similar looking body kits that were available at the same time.

Back then you bought the car first and then chose what you wanted AMG (or their agent) to do to it - so it could be anything and everything from the AMG list of parts/services, or something bespoke.

It would be possible to order body styling only - and some did - or order mechanical upgrades and keep the exterior completely standard for a more subtle look. Some ordered the full monty.

 

[tonysmb]

I had a feeling it was done that way but couldn't remember; I do recall that back-in-the-day AMG were more akin to Alpina than they are now and there certainly weren't many genuine ones around.

 

[GazEddy]

Thanks Ray, although that would be a great swap, the engine is definitely too big for what i need.

Im hoping (and being clearly foolish) to keep the build under 10k. to get it roadworthy anyway. Im sure it will be an even bigger money sink over time.

I'm no expert but, from reading many forums, the project you're planning is inherently complicated and costly. But possible.

I'm sure that a modern Mercedes V8 plus a manual gearbox and all that goes with it would be stunning. Or what about the 600 V12? I've seen those in a W201 and W124.

So, an interesting project but prepare yourself for serious, 5 (?) figure investment.

RayH

 

[GazEddy]

Hello and welcome . a N/A M113 V8 would probably drop right in . Quite a few used ones for sale out there. Chasing economy is going to be expensive IMHO.

Go on YouTube and find Anderzén , he is (by his own admission) just a young bloke working out of (what appears) to be his dad's garage and trying stuff out on various old MB cars.

He put a manual transmission in a C55 (M113 V8)

Thanks Pete, after a bit of research that is top of my list currently, as they are relatively cheap to source and buy. It being a direct drop in would be ideal also, I'll continue to research this.

 

[GazEddy]

Just out of interest, what makes it an "AMG" car? If it is fully fettled by AMG at the time of delivery I would have thought it would make it a pretty special car and any changes to it (putting a Jap engine in) would devalue it far more than you'll benefit by improving the fuel economy. If it just has an AMG badge on please ignore my post!

From what I can see, just a styling body kit and alloys. I don't know if the engine is a slightly higher output version over the original.

 

[Petrol Pete]

Gaz . Not sure of the accuracy of this but I did hear there was just one brand new M113 5.4 AMG engine in stock ....35K Euro !! .

Could just be an urban myth.

 

[Petrol Pete]

Alex at Legitstreetcars is an ex MB technician . His earlier content includes a load of 'older' Mercedes Benz cars. He has posted 2 videos on this 'Pre' AMG car. Look for the bit where he checks out the camshafts to see if the engine is a 'real' AMG.

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[GazEddy]

Gaz . Not sure of the accuracy of this but I did hear there was just one brand new M113 5.4 AMG engine in stock ....35K Euro !! .

Could just be an urban myth.

Hey Pete, I think i'm probably going to go for the 5L M113 due to its price at the moment. And after a bit of research, it seems the manual transmission from the M112 will fit it too, so that may be the best option going forward.

That is stupid money for that!

 

[GazEddy]

If you are considering a transplant, the first thing you need to get on top of is the final drive ratio. It seems that for V8 SECs 3.07: 1 is a low ratio and that a numerically lower (but 'higher') FD is likely. Not surprising as AFAIK the 4sp auto box has a direct drive (not over-driven) 4th gear. Any manual box you intend using will inevitably have over-driven upper ratios and with a smaller engine will be unusable. The lower ratios with a high diff will also be high and 'gappy'.
Unless you intend using the car for high(ish) speed M-way, A-road cruising (and get appropriate) gearing you may find no economy benefit from a smaller engine as it will be working so hard it will probably be running rich (self preservation) a lot of the time and a turbo motor will likely respond best to high octane (read - expensive) fuel.

If this car was mine I'd be considering refreshing its own engine and converting it to LPG (a single point system could be put together for under £1k, compatible - I think - with the standard KE Jetronic system). My 260hp 2-2.5 ton truck on LPG is returning the fiscal equivalent of 35mpg. By comparison, a transplant - any transplant - will be a carnival of pain.

I never even considered an LPG conversion tbh, but due to the state of the current engine, it has to be a swap at this point.

hopefully with the M113 engine, and the fitting m112 transmission, gearing and ratios wont be an issue, but thank you for the advice, I definitely wouldn't have thought of that.