engine swap !!!! - PeachParts Mercedes-Benz Forum

tko619 · #1 12-05-2007, 03:03 PM

hello everyone this is my first post about my beloved w111 250 coupe. im very happy to be a part of this team and i'd like some feedback on a conversion i'd like to do, heres my challenge..... ive got a 1965 250 coupe with an inline 6. i want to take out the 6 and install a motor out of a 1979 450 sel with cis injection system !!! my question to you all is WILL IT FIT ?

Mike D · #2 12-05-2007, 04:07 PM

It'd "shoe-horn" in there but why?

For starters, you'd have to change:
Transmission, front drive shaft, trans mounts, complete exhaust, most of the gauges (the '65 was all manual), probably the steering gear box (hose locations), all the acc. linkage, trans linkage, radiator, fuel tank and lines, the ignition circuit, A/C lines and compressor and possibly the power brake assembly set-up. That's all I can think of off the top of my head but I'm sure there's more.

cth350 · #3 12-05-2007, 10:01 PM

A straight-anything => v8 conversion is usually tough in the cars before 1977's W123 family. You're better off with another straight motor (4/5/6 cylinders). A 111 coupe is a lovely car and can be valuable if it's in good condition and somewhat original, or at least, converted back to original.

A straight-6, carbed motor is probably the simplest to get. A 250se sedan would provide the identical motor to what you already have.

search the archives here and you'll find lots of people that have considered the v8 swap and a few that have actually tried it (good luck finding one that succeeded). You will need to cut out the current transmission tunnel and refit a larger one to get an automatic under the hood. Also the brakes and suspension will need to be upgraded. A donor 280se 4.5 is the recommended way to go for that.

Having said all that, what's wrong with the original motor? They are fixable after all.

-CTH

Tony H · #4 12-07-2007, 11:51 PM

The engine should physically fit just fine as it's physical deminsions are similar to a M116 as installed in a 111 3.5. But as previously mentioned it will be a major peoject. I believe the steering gear box is different on the V8 cars also due to the very close clearance to the left exhaust manifold. And the engine will be running at much higher RPM's that the car it came from.

cth350 · #5 12-08-2007, 12:06 PM

there are two kinds of 111 coupes, referred to as "high grill" and "low grill" models. The 3.5 fits into the low grill ones. That in fact, was the reason for the change. -CTH

Tony H · #6 12-12-2007, 06:23 PM

There were 6cyl as well as V8 low grill coupes(and cabs) produced. The basic chassis was esentially unchanged for the entire production run. The low grill is a minor sheet metal update.
Tony

cth350 · #7 12-12-2007, 07:59 PM

None of my 111 or 112 coupes are handy to measure the inside space between the two frame rails. Anybody have one of each car and a tape measure handy? -CTH

Tony H · #8 12-12-2007, 08:45 PM

Hi,
The engine is presently out of my 3.5 coupe. I can measure it tonight.
Tony

have mercy · #9 12-12-2007, 10:27 PM

Hey cth350 glad to here it from you.You know me i wanted to install 4.5 in 61 220 4 speed .I would have tryed to made it.looked at dog box ,had to replace, change undercarage. Would love to have it like that. know maybe i would not go that way.

Tony H · #10 12-13-2007, 07:07 PM

29.25" at the subframe mount(Width varies depending on where it's taken)
Here's a entertaining page about a gentleman who has done several 111 6.3 conversions.
http://www.m-100.cc/6point3/magazines/carcollector_sep1982/index.html

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