Swapping the 6 for a 4.5 v8 in 114

Hello. I just recently came across this forum. I was wondering if anyone has heard or seen a 4.5 in a 114 chassis coupe or know if it is possible given that the engine compartment is a little smaller than other coupes with v8 engines. I know that the sub-frame is the same as a 107 chassis. Does anyone have any dimension statistics about the 4.5 v8?

Mark

[wbain5280]

You might try searching in the forums for previous entries. The consensus seems to be that you cannot do it.

If money is no object, you can.

Although it would have nice to see a Mercedes V8, it does at least show what can be done. This is in the confined space of a w123 engine bay!

[psfred]

No go unless you also replace the front suspension with something narrower -- the exhaust and upper control arm will occupy the same space.....

Peter

It would be less expensive and more effective to sell the w114 and buy a w108 or w116 with the engine already installed.

Well it's not going to be very expensive because I already have a shop and a mercedes mechanic to work with...without the high cost. I am just trying to find some information and do some prep work before I try this. Also the car has some sentimental value and it is in very decent shape and has undergone some changes since the factory. A sunroof was put in. as soon as i track down the pictures i will post them.

Mark

[300SDog]

Can understand your logic...... if the straight 6 and V-8 are interchangeable in the larger sedan, they could also be swapped in the smaller coupe - yet this only tells us motor mounts and tranny bell housings might be compatiable.

What about the gear ratio at the final drive..... probably the pumpkin from 107 or 116 will fit, eh?

Undercarriage exhaust system is just one item to consider.

Also think about the size and shape of the sump, space for stuff like power steering and A/C compressor.

And the fact you are replacing carburetor engine with fuel injection. Electrical system?? Vacuum line system?? Fuel delivery and return lines??

This sounds like ambitious project that should not be attempted unless you've got an entire 107 donor car for all the miscelaneous fiddly bits.

If it was me, I'd park the car next to an approximate year 450 SL or SLC..... then take lots of detailed photographs and measurements - better yet get opportunity to examine the 6 and V-8 engines, side by side, out of the car.

[ctaylor738]

There are a bunch of Chevrolet V8 swaps into these coupes. Try an e-Bay or google search. I have never heard of a 4.5 swap. If you are going to pursue this, a 3.8, 5.0, or 5.6 engine might make more sense since they are all auminum and therefore lighter.

IMHO a M103/M104 (3.0/3.2 six) swap would be simpler and yield excellent results.

That is a fine looking coupe!

[73MB280SEL]

I agree with CTaylor, there are alot of V-8's in other vehicles. I don't think a V-8 is much larger than a I-6 and it certainly need not be heavier. I-6's are wonderful engines but they are darn long, big, and heavy. That's the main reason they are not used anymore.

I'd think that a MB V-8 from the same era would give you a head start in conversion over a Chevy small block due to the front oil sump. You'd still have to deal with hooking it up to the radiator, driveshaft, motor mounts, exhaust, and clearing the steering gear.

Sholin

p.s. My favorite conversion of a 114 coupe (preferably 250C that has the prettier bumpers and wing vent windows) is a Diesel with a manual tranny. The thing I keep seeing is a mint looking and perfectly stock 114 coupe with either a Sprinter engine or one of the new Jeep Liberty Diesels installed.

Of course a Chevy LS1/T56 would be pretty cool to as far as swaps go.

[psfred]

I repeat:

It is physically impossible to put ANY V engine into a W114/W115 chassis unless you cut out the brace rods and remove the front suspension -- the upper control arm inner pivot occupies the space where the head and exhaust manifold are on a V8.

You could, of course, remove the front subframe and cobble up some sort of a front end that doesn't use an upper control arm, but you will then turn the car into a piece of junk. The coupes are fairly valuable, unlike the 4-door sedans.

Peter

this has been done already by Derek Jettmar from Florida who in my opinion is a mad scientist with crazy talent.

Just look what he did with this sl.
http://www.ritzsite.net/280SL63/01_SL63.htm

and what he did to this 114 coupe.
http://groups.msn.com/Mercedes300SEL63/madmandereks280sl63.msnw?Page=2

There is his email on this page so give it a try. He sure should know how to do it.

[psfred]

Yipes! And I thought a 4.5 was a close fit in a W108 chassis!

One thing is certain -- you will have to remove the two tubular braces from the center of the firewall to the front frame section, and this will SERIOUSLY weaken the frame, to the point that I would expect front end vibration problems (as you get in most GM 70's midsize cars -- you can see the front fenders bouncing independent of the rest of the body).

You will also probably have overheating problems, as there is no place for the air to go around the engine, and I suspect you will have to use maifolds off of a W116 chassis -- that's what is in the pic. Considerable custom exhaust work, too, to get the engine to run properly, and there isn't much room underneath for the dual pipes.

However, anything is possible if you want to pay for it.....

The article does not mention suspension mods, or hood/fender mods, either -- that 4.5 is pretty wide and tall.

Peter

If you are talking about the black sl it looks like the hood is modified to open from the windshield side. I don't know if sls open like that. Also he had some issues with the hight of the engine and had to do some work but overall what he did is just freaking amazing. I don't remember if he also transplanted the air suspension but I doubt it. Once on the m-100 board he mentioned how the rear goes sideways when you try to show of some rubber burning. Search the archives at www.m-100.org for some old threads on this sl.

SWEET! Now that is what I wanted to see. Now I can start my mission. Thank You 300se6.3.

Mark

[Tomguy]

Mark: The reason the guys here really dont want to see you do it is because it WILL lessen the value of the coupe! A coupe, especially one that looks as nice as yours (ESPECIALLY if that's the original paint job) is worth a considerably large amount of money. You could sell it and buy at LEAST 2 108's (w/4.5) in near-mint to mint condition with cash left over! But the conversion will make your coupe have well less than half that value!