M117 into W114 engine swap?
 

I'm new to this forum and I'm looking for help with my engine swap project. From what I understand after days of searching is that the least complicated option for a V8 swap into the W114 chassis is the M117 engine type. I have access to a complete 1989 560SEL donor car at a reasonable price. I have learned that W114 and R107 engine bays are essentially the same but are the tunnels too?

Specific questions I have:

- is the tunnel on the W114 large enough for the automatic transmission from a late W126 560SEL? If not, what type of modifications are required?

- can anyone confirm if R107 motor mounts will work?

- are R107 exhaust manifolds required?

- can the W126 ECM be used and how would it be wired in? I haven't been able to find a wiring diagram yet.

Thanks in advance for your help!

Lot of work for very little gain. Save yourself the trouble.

Between re-working the fuel, ignition, braking, exhaust, drive train and myriad piddling details you are talking a LOT of work.

Will it fit? Yes. Is it worth the "power" gain? No.

You'd still have a 3000+ pound chassis you are pushing around.

Your car, your money.

you might be right... I'm looking at other options now.

As CTH pointed out in the other thread, the M104 conversion would be a better swap. Still a lot of work but without the added hassle of trying to shoe-horn the M117 into the engine bay.

It has frequently been mentioned that the R107 and the W114/115 chassis share the front crossmember and the engine mount location. The key distinction is that the 107 engine bay sheet metal was designed to accommodate the M117 engine. The 114/115 engine bay was designed for only inline engines; not the additional width of the M117.
The narrower confines of the 114/115 favor the small block Ford (SBF), the slimmest of the US V8s. The SBF with either a T5 manual box, or AOD autobox can be installed without disturbing sheet metal.

The 302 V8 is a very well-supported engine in the aftermarket community. I wouldn't hesitate to use one if you aren't hung up on MB engine originality.

An LS engine would also fit but you will need to modify the crossmember, or oil pan, or both. You will need to cut and re-weld the tunnel, as well, for the transmission. It's more involved, but it's been done / is being done.
http://www.peachparts.com/shopforum/vintage-mercedes/378762-69-230-build-w-lq4-swap.html

In the end the questions are:

1. How easy do you want the swap to be?
2. Do you want more power?
3. Do you want an MB engine or not?

If you want more power, the LS family is the way to go. Not that the 302 is a BAD choice. You can get 500+HP from a 302 with a stock bottom end with a turbo, but it won't last too long - and any more will probably split the block in half - whereas a mildly tuned LS/LQ can get 600+ reliably.
The LS, at this point, is EASIER for me to find than the 302 in junkyards around me. Most 302-powered cars have been crushed already. New LS/LQ vehicles still arrive daily.

If money ISN'T a factor AND power isn't a factor, go with the M104 or if it fits the M110 (I think it does but Frank can correct me). It will be more expensive to find a good MB engine or rebuild a worn one, but you'll have an MB engine.

If you want cheap and easy, 302 with its factory carbies (or find one with the harnesses, fuel pump/injectors etc. from a later car or just find a junked 1994-1995 SN95 GT for $300 at Copart).

If you want something more reliable with more power, the LQ cast iron engines are not that expensive and you can probably pick up an entire Express van for under a grand with fees. For example, there's at least 2 6.0 Expresses on Copart right now with Buy It Nows of $800 and if you wait for auction you can get one of the non-BIN ones for probably $500 plus fees.

If money isn't a factor and you want lighter-weight power, the aluminum-blocked LS engines are the way to go. You can use the factory harnesses and ECU etc... or even aftermarket controllers if you wish. Looks like wrecked CTS-Vs sell for less than wrecked Camaros and Corvettes...

Glad to oblige, Tom. The M110 was the OE engine in W114s '73-'76. Very expensive to make even 300HP w/o boost.

Thanks for the information! What I really want is a reliable engine and transmission combination that gives me a minimum of 300HP and 350-400 lbs of torque. A late 560 M117 would be in the ballpark but barely so. If I used a late 560SL as donor vehicle engine and transmission might fit in without major issues.

On the other hand, an LS engine is easier and cheaper to find and will easily give me loads of torque and horsepower. Originality isn't really an issue for me - an engine swap ruins that no matter which motor I pick.

At this point I'm leaning towards an LS engine. I think it is a much more involved swap but I'll get the power I want and then some. It will also be much easier to source parts etc. Lots of aftermarket options for just about anything.

I don't have time and a space to do this myself so I have started talking to a guy here in the Phoenix area who is specialized in this type of conversion. It won't be cheap but I think I'll have what I want - a W114 coupe restomod. I really like the /8s but I also like V8 power.

Thanks, from what I've learned so far it pretty much comes down to V8 options only.

the M117 won't fit. M116 might fit. You'll have no space for manifolds.

Thanks for commenting. Not enough room between the frame rails or is something else in the way?

yep

The 117 is too wide as Frank and Al pointed out. I doubt a 116 would fit either (I thought the m117 was only like 3cm wider?)

With the work and money you'd spend getting a 5.6 to that power level, you'd be spending triple what a mild LS would cost, nevermind the work to get the bigger 5.6 to fit. The biggest issue is what Frank pointed out - and I'd believe him in knowing - the AOD for a 302 would fit. We know the 4L transmissions don't fit, as the other conversion thread I linked showed. So that will involve fab work, but much easier work than modifying the unibody rails to try to get an m117 in.

Also throwing it out - I don't think it's been done - a Gen III Hemi would probably fit too, and the 5.7 stock is 345HP / 345TQ for the mildest / oldest version (LX Car engine manifolds). The truck engines breathe a bit better and have more.

I've seen a 116 in a W114 engine bay, there's a bit more room but you'll still have to make custom headers.

Forget the V8. M104 is the way to go or get a W123 which will take a 560 motor without too much heartburn.

Thank you everybody, great information! I'll get back to you once my project starts and post project steps.