Engine Swap Questions M120 into 380SL
 

I have a few questions about the possibility of putting an M120 into a 380SL

1) Will a 380SL transmission phyisically bold to an M120 Engine.

2) If so are there any ways to strengthen the 380SL trans.

3) Is a 560SL trans built stronger than a 380SL trans.

4) Assuming I have to get a transmission out of a S or SL 600. Is it likely that this transmission 4 speed or 5 speed version, will bolt in place and mate up to my drive shaft.

5) For the electronic controls on the S or SL 600 transmission, are they a seperate wire harness and computer. Or are they integrated with the engine controls.

6) Does anyone know the rear end ratio of an SL600 or S600

7) Is there any easy way of matching the speedo gears for mismatched rearends.

8) Does anyone have any dimensions for an M120 Engine.

Thank You
John Roncallo

Sorry for not getting back to you sooner. Here are a few of the answers.

1) Wrong bolt pattern. You could have a custom bellhousing made, but it would shred the trannie.

2&3)I would use the new 4/5 speed from the donor car, as the electronics would be the limiting factor for you auto. Not to mention it would also be the stronger candidate for you.

4) Custom driveshafts are cheap to get built. You just need toi make sure it is balanced that way you will not have any excessive vibrations.

5) It is seperate, but I think that the computer may just trip out without the computer. (I am not 100% about this, but that is what I was told by the mechanic.)

6) It is discussed that the SL600 has a rearend somewhere in the neighborhood of 2.65:1 or somewhere around that. I was considering looking fir something around a 3:1 rearend so I can get 0-60 in under 5.5 seconds.

7) Yes there is a little box that will allow you to recalibrate the electric speedo so that is read correctly.

8) I have those measurements for you. Sorry I haven't posted this earlier, but we had to move everything out and back in fo some carpets and walls to get put it. I know that the paper with the info is in the garage. Ill look take a gnader and see if it still exists, or if it has disappeared.

Let me just say "BAD IDEA" alltogether. The M120 engine is huge and every aspect of installation into a 107 chassis would be completely custom as nothing would bolt up to anything or fit within the existing spaces. Assuming the impossible, that chassis is so under engineered for the weight and power of an M120 that it would be a death trap with one installed. You could easily buy a fleet of 129 600SL's for the cost of retrofitting M120 into a 107 chassis and making it even remotely safe enough to drive.

i dont have hard info
 

but i would think it should fit. we are talking of the v12, right? that engine is just two sixes on a common crank more or less. the 107 came with a six in europe which i suspect is longer than the newer sixes, and it came with a v8 which i suspect is no wider than the v12. now granted the top side of the v12 will look very massive with the twin cams etc, but i think the interference points are lower at the inner fenders. so before dismissing it out of hand, unless the previous poster has actually measured it or tried to put one in and it didnt fit, i would put a 107 next to a v12 eqiupped car and carefully measure everything.

now the question of chassis integrity is another issue. although it is certainly not likely to be as strong as the newer car, that chassis came with some pretty potent v8s expecially in europe, so bigger diffs and brakes should bolt right on.

the question of electrical compatability is something i have no knowledge of.

so if you are really interested i would continue to explore for hard info.

tom w

Trust me, the M120 is a very wide engine top to bottom, the 380Sl has a very narrow engine bay. My co-worker had to hammer on the frame rails to swap a 5.0 into his 107, originally a 380. Hey, I'm not saying it can't be done, money will do anything. I'm saying that if you strap a 1 liter 145hp, 14k rpm engine onto a moped, it's not gonna be even remotely in the same class as a FZ1, now change moped to 380SL and FZ1 to 600SL and you get my meaning. By the time you re-engineer the moped to be competitive you've spent way more than an FZ1 costs.

so you're
 

saying that a 5 liter wont bolt into a 107?

they came from the factory with 500s and 560s, do you suppose they completely redesigned the frame to fit in the later motors? also the 350 and 450 are 116 and 117 engines too. so i bet the 450 is dimensionally identical to the 500 and 560.

i still say measure both and see what you find.

it might not be practical for many reasons, but i would be surprised if the engine being too big is one of them.

tom w

This is my take on it with only seeing pictures of the engines so far.

1) I estimate the engine will be about 7" longer, which means it wont fit lengthwise without moving the radiator. You have about 1" to move the engine back. If you take the one 1" you should now have a shoe horn fit. Radiator may have to be removed and replaced with a thin single core unit along with two small electric fan cooled radiators on each side.

2) It looks like the intake manifold may hit the brake booster. The brake booster may have to be moved under the fender and actuated with a bellcrank and linkage.

3) Where the engine bay in the 107 gets narrow is down about exhaust manifold level. The M-120 has wider heads but it is also a 60° V instead of a 90°. Hopefully these two facts wash out.

4) Totally unknown to me is the placement of the oil pan sump in relation to the sub frame. These can be modified but I'd rather not. There are also 2 oil pans for the M-120 one for the SL and another for the S. This widens the choices. But I belive the SL one (Forward Sump) is more likely a better solution.

5) Engine height unknown

All the reast of the stuff is the standard swap engine problem.

John Roncallo

Thanks Justin, I will be looking.

John Roncallo

pretty
 

excititng project.

hope it works out for you. you will keep us posted right?

tom w

I actually find this encouraging. I assume you are talking about an M119 5.0. Without measuring I would assume the M119 is wider in the exhaust manifold area where I am most concerned. The M119 is a 90° V8 with 4 cams and larger boars. With all other things being equal in design the 119 should be wider in this area.

As far as weight of engine, I am not too concerned because earlier 107 used iron block engines which I dont see being much lighter. Also I have already put a 302 CID Ford engine into a Pinto and a 350 CID Chevy engine into a Ferrari 308. Handeling takes a beating but they both worked well. To me the M120 installation into a 107 is a reasonable fit because it really is as much power as I dare push through a stock rear end. I'v also considered an AMG 55 engine, but with 100 extra HP over the M120, I have to be concerned with the rear end.

By the way do you have pictures of the M119 in the 107. This is another option I,v been considering.

John Roncallo

i woulndnt be
 

surprised if the 120 engine is lighter than the iron 4.5

tom w

The 5.0 that took hammering on the frame to fit was a 117 not a 119:(

I stand corrected. I conferred with the tech who put a 5.0 117 into his 380SL, no hammering, just had to cut 4 inches out of the frame to fit the 5.0. So yes the chassis has to be modified to fit even the larger V8. The V12 dwarfs those V8's in comparison.

As fas as upgrades for brakes suspension ect. Every vehicle that M/B sells with a V12 option has brakes that are much bigger on the V12's than even on the V8 cars. So yes there are upgrades for the 107's brakes and yet they will still come in as inadequate for the massive amount of power and weight of the 12.

I'm sorry but my BS meter is pegged hard over. When the 380SL was being sold over here in the USA with a 116 3.8L V8, it was also being sold in Europe with the 117 5.0L V8. I doubt they had two different chassies.:bsflag:

John Roncallo

me too
 

the only plausible thing that might require that is if he didnt have proper sl exhaust headers and tried to use sedan's.

could you submit pics of the car with the cut frame? i would be very interested to see which 4" he is doing without.

tom w

Sorry but I don't have pictures of someone else's car. The area in question is near the idler arm, that I am sure of. And yes the 5.0 was offered but there was more room engineered into that area for those cars, which yours is not. I'm not trying to B/S you. I am a 10 yr M/B tech. On any given day i can be working on both 107's and V12 cars. Heck, there is a 380 SL in my shop sitting without an engine in it. I know exactly how much room you have. I also mentioned the idea around the shop (mercedes only independant) and everybody chuckled and then agreed, "no way in hhell"

I'm sorry that I'm the only voice of reason here but I am trying to tell you that you have no idea what it will take to put a m120 into a w107. I can promise you it will exceed any notion you have by an enormous percentage. As a rough guess I'd bet you'll have to re-engineer at least 50% if not 75% of the entire car. If it were even remotely feasible don't you think someone would have done it by now? Hell, I've seen V12's stuffed into a C-class but you're talking about a 6 figure price tag on the conversion. Are you really serious about dropping that kind of scratch on one of the lamest of all SL's?

Sorry I dont mean to start a flame war here. But so far you have given me no useful infomation. If you want to help give me the number in inches or pounds that you feel is going to knock this project out of the relm of practicality. I have also worked on MB for 10 years from 1978 to 1988 so I have never seen an M120 engine except in pictures. I have done some challenging engine swaps including Chevy 350 into a Ferrari 308 GTS and Ford 302 into a Pinto. I have recently seen an artical on the web of and M100 6.3 iron block engine installed into a 113 280SL. I'm sure that engine is much heavier than the M120 and the car is smaller than the 107. I am now an Areospace engineer and quite well acustomed to such challenges. I also have a full machine shop at my house.

Numbers please, "no way in hhell" is not a number

John Roncallo

The best "useful" information I can give you if you are determined to pursue the project: Get rid of the 380 and get a solid 560 SL and start from there. The 560 is the better enginered and built of all of the 107's and is where any serious attempt at a V12 W107 should start. Take that to heart. I'd really would love to see you pull it off. (I've built a V8 pinto myself.)
I think it will require an extensive front suspension and subframe modification. The tranny tunnel is really low in that chassis and getting the 12 to sit low enough is gonna require a lot of room that isn't there to start with. The 107 doesn't have the typical "firewall" space so you have to get all your "extra" space low and forward. You're likely to have interference at the steering gearbox, idler arm, and possibly upper control arm inner mounts, as well as the subframe, drag link, and damper. The subframe ties the front suspension together and any serious modification will essentially require a redesign of the front suspension. As mentioned before, the brake booster is gonna interfere with the intake which is huge. You're gonna have to get creative there. Something like a hydraulic brake booster maybe? A rack and pinion may just solve the gearbox, idler arm drag link issues. The 560SL has a diff I believe strong enough to hold up to a 12 and hydraulic rear shocks. The hydraulics in the rear have a "ladder bar" affect in that it lifts the rear of the car during a squat, (ie hard launch)
No flame war intended. I should have realized that "trust me" wouldn't suffice for a reason "why not" :D If you are up to the task, then kudos,:D go for it. But as you may start to realize it will be a major undertaking. If you're emotionally attached to the 380 SL then build up a V8 and concentrate on upgrading the chassis to 560 specs. You'll find that to be much more rewarding. You'll be able to upgrade different things along the way and be able to enjoy the car in the meantime. The option is to strip the whole front end off the car, position the engine/tranny, and re-engineer the understeering, stoplight terror around it.

if the booster
 

is a problem, and i can see how it may be, i bet 107s were offered in some markets with manual brakes. i know the big bimmers (euro) were at least around 1980. i drove one. it worked fine. i suspect that the non power master may run a smaller diameter piston for more mechanical advantage.

tom w

I actually do not have the car yet. The 560SL is the chassi of choice if I can find one.The 380 was mensioned as a worst case starting point from the possibility of using a modified 380 transmission. But since it wont bolt up to the M120 and the are no B&M performance parts available for MB transmissions use of the stock transmission has become a moot point. At this time I am looking at a 560 with 200K miles on it. A straight body is my biggest concern.

The tunnel area I belive I should be able to be enlaged and still use the stock console. Keeping the car stock looking inside and out is one goal. The subframe is one part that may make the job somewhat easier. The subframe can be completely removed and redesigned allowing me to work arround obsticles.

The power booster I'm not in the least concerned with. But I belive the radiator will have to go and finding a safe place for those might be challenging.

John Roncallo

just a quick aside, but the 560SL is standard suspension, @ least all the varients (including my own) that I have come across. An SL w/ SLS sounds interesting though!

You might want to consider, given the space limitations, installing the euro spec oil and transmission coolers. They sit off the side, typically under the front fender wells. Going this route might make it possible to cut down on the overall size of the rad you will need. You might talk to Ron's radiators, the work they do is first rate.

Just to add some more conversion work fuel to the fire I'm waiting on a C36 driveline to show up so I can start adapting my 64 Austin Healey to run it...Should be fun:)

Best of Luck!
Jonathan

This elegant debate is more interesting than my 280C with American v8 ponderment. Can the previously otherwise mentioned Mustang II front end solve the problem, or are we looking at the Ford assembly being too light, or is it a MB manhood issue? If I was gonna stuff that beast v12 somewhere, it would have to go mid-engine for center of mass. gravity, and inertia. Sure wouldn't want to enter a wet road under yaw and power with it hanging out the front of a "moped". I'm going with the souped v8 and suspension improvements.

i doubt
 

that the v12 weighs much if any more than a 617 turbo.

but if you want to go with the ford, i am pretty sure they were available with several sump locations. check bronco and truck listings and see if you cant find one that fits a benz.

tom w

280C engine swap??
 

Hey Bobsterman,
Sorry to depart from this interesting discussion on the merits of the V12 swap, but I have to ask the Bobsterman about his "ponderment"! I have a nice '75 280C, and have considered installing a GM 4.3L V6 to replace the very tired 110 engine now residing between the front wheels. I have also considered just installing TBI injection on the 110. My only problem is that I'm getting too many Benzes, and I'm not sure my '75 is worth hanging on to. I already put a 4.3L V6 in my '82 300D, which worked out REALLY well, and made a wonderful car that gets great mileage and has plenty of power.
http://www.freewebs.com/rwooldridge/mercedes.htm
Have you considered the 4.3L V6, or do you just want the cubes of the 350? The V6 makes a goodly amount of power, and is thrifty on gas.

Richard... this "choice" is not exactly as it appears... I was, for the purpose of the thread's author, imaginatively "choosing" from the interests here in this thread. Please toggle over to my post "Newcoming..." for the specifics of my "ponderment"

http://www.peachparts.com/shopforum/showthread.php?t=148793

An M120 engine is on it's way along with the rest of a wrecked 96 SL600. I still need the doner 107 chassie. Anyone have a lead on a 560SL with a good body but blown engine.

John Roncallo

say roncallo
 

mind saying what you paid for the wrecked car? pm me if you like.

tom w

Yes, how is the interior of the SL600, would you be willing to part with some of the parts if they are the right color?

The car I bought sight unseen as an insurance wreck for $6900. Plus about $1200 shipping from CA to CT and 300 Ridesafely.com fee. It has 46K miles and was hit on the left front. I hope the engine is OK, there does apear to be some damage at least to the intake box on the left side. The car is either blue or black with a grey or blue interior. Everything aft of the firewall looks excellent. Depending on how I evaluate the car, I will either part it out or just borrow the engine and trans for sizing and research for fitment into a 107. If its worth rebuilding I will rebuild it.

I missed on a 97 flood car that appeared to be in a very minimal flood and went for $9900.

J. Roncallo

cool
 

i would prob go for a wreck if not too extensive over a flood car.

i find your project very interesting and i will be very interested in hearing about it if you go ahead with it. i understand that rebuilding the wreck probably makes more sense financially, though.

tom w

You can buy my 560SL with a working engine for less than $7 grand. The body is not perfect, but very nice. Higher highway milage car. It'll be in New York in a little more than a month.:)

There has been a bit of discussion in regard to engine weights in this thread , so I thought I would clear the air with my 2 cents worth .

1. Mercedes SL600 ...........................581 lbs

2. Mercedes 450SL Iron Block..............540 lbs

3.Mercedes 500SL Alum Block.............452 lbs

4.Ford Boss 429 Iron Block Alum Heads..680 lbs

5.Chevy Small Block V8 in 60's 70's.......575 lbs

6.Chevy Big Block V8 Mark IV ..............685 lbs

As can be seen the SL600 is about the same weight as a small block Chevy, so should not have weight issues transplanted in a 380SL .

Some one made a comparison between the SL600 and the SL55 .

The SL600 is a twin turbo V12 and the SL55 is a blown V8 , they have almost the same power ratios except the 600 has more torque but with more weight and a turbo, instead of a blower .

Den Downunder 1982 500SL Euro Red .

Thanks for the reply Den. I was looking for this info, where did you get the numbers.

I just got the SL600 doner car and the 560SL will be in from California in about 2 weeks. So far my measurement show this engine to be physically smaller than the 117 engine both in length and width, at least down below where it counts. I expect to have difficulty in the power booster area and the AC compressor and PS pump may also have to be relocated on the engine. The 5 speed transmission also looks bigger so the tunnel may have to be modified.

The biggest problem I'm having right now is that the SL600 looks repairable and I may just want to fix it. In any case the engine will have to come out to do the repairs, so I may just borrow it for a bit.

John Roncallo

cool project.

keep us posted.

on the engine weights it is hard to imagine that the 600 weighs 130# more than the 500. is it a four cam engine? if so, i suppose that is where all the weight is.

tom w

Guy's,

The weights were obtained from a few different sources on the net , in particular the SL600 was hard to find , however I had verication from two seperate sources off the web.

The SL600 engine is amazing when you look at all the area's of engineered weight savings , they used magnesium and aluminium extensivly and many areas are hollow where you would expect solid metal.

as I said I got most of the info from one source , but had to do a seperate search for some including the SL600 and 500SL weights.

The main source http://www.team.net/sol/tech/engine.html

Or Engine weight FYI

It was a bit of work but interesting to come up with the numbers.

Den Downunder 1982 500SL Euro Red .

Sounds like a plan, man!

M120 107 Update
 

I have begun the project of fitting the M120 engine into a 1986 560SL

Attached is a picture of the M120 engine sitting on a 560SL subframe. As expected there will be modifications required to the fit the engine to the subframe correctly involving cutting the front cross brace and moving it forward about 1 inch as well as making the rear cross member more shallow to drop the engine low enough to put the crank axis at the same height as the 117 engine.

Prelimiminary indications are as follows

1) Interfearance will exist between the master cyl and left hand air intake boot.
2) The oil filter that I originally belived I would have to mount remotely appears to fit snuggly.
3) A special manifold will have to be made to acess the oil cooler lines.
4) I originally thought the AC compressor would not fit at all. At this time it apears more promising, however a special manifold will have to be made of a narrower compresser will have to be found and adapted.
5) Preliminary measurements indicate the engine front edge will hit the hood. The hood line may have to be worked. This is one modification I did not want to do as the 107 hood is the most beautiful body part on the car. The possibility of droping the engine an inch makes the situations 2, 3, 4 worse
5) Exhaust routing is too difficult to evaluate at this time but it does apear that is is an area where I will have to cut into the chassi.
6) Any rumors you read on this thread about this engine being extreamely heavey and might flip over the engine crane are false. The engine was very easy to remove with the transmission attached. I did it unassisted by myself. Any one who thinks this engine is heavy has not removed a big block Ford FE series engine.
7) I will have the engine weight shorltly
8) Nothing impossible or overwhelming yet however I will have to be carefull to avoid a situation where removal of the AC compressor requires removal of the engine

John Roncallo

sorry for my ignorance....is that a four or two cam engine?

clearance for the brake booster might be had by twisting the engine a bit.

i did that on my q-jet carb conversion on my 74 bavaria. shimmed the engine mounts about 3/8" or so on the drivers side.

it also might be possible to move the pedal assembly over a little.

cool project!

tom w

4 cam. The engine cannot be twisted or the oposite corner will come through the hood. This is a 60° engine with manifolds coming over the heads. It is very tall engine.

John Roncallo

Remote booster? Read on Lancia Scorpion or I belive MG B's? I'm not the one under there, but worth checking out, maybe put the MC in the car, then route the lines underneath, then into the booster, then out to the brakes. Kind of a PITA but it works.

i figured you were way ahead of me but couldn't resist suggesting it.

you might also be able to fit a smaller booster.

tom w

FYI, the GM LSx series engines (LS1 - 345 HP, LS2 - 400 HP, LS6 - 405 HP, & LS7 - 505 HP) are all Small Block Chevy sized and weigh approximately 434 pounds complete (LS6 value). These are all aluminum engines and very recent designs. The oldest one in the list (LS1) came out in 1999, the LS7 is about a 3 year old design.

More HP, less weight, better fuel mileage than an MB engine.

This is my LS6, silver and blue since my 560SEC into which it's going is a silver car with a blue interior. This engine has a cam and some valve train work and has been measured at 410 RWHP, about 475 HP at the crank. It's about 1/4" wider than my M117 engine and 3/4" longer, and since the intake is on the front of the manifold, it's lower than the M117.

YMMV

If you were doing a 4.3 V6, why not just go with a LS series V8? The 4.3 is just a SBC 350 with two cyls lopped off. So the width would be fine and the depth should be ok too. Wonder if a LS series engine would fit into a w114/5? Hmmmm...

I looked into an LS7 $15,000 for the engine. then I need a trans (The idea of a 6 speed standard was apealing). Then I need all the wireing harnesses. Then I need all accessoris. And on top of all that just as much work for the install. Approximatly $22K for all the hard parts less any custom fabricated stuff. I got a complete SL600 wrecked delivered from CA for $8300.00. Its got all hard parts I need. From that point on the cost is approximatly the same.

The MB SL600 engie advertises only 389 HP however it has been my observation over the years that MB uses a bigger horse.

When I am done I will have a Mercedes with a Mercedes engine a 12 cylinder MB engine. Also the engine is not too over powered that I will have to be concerned with the rest of the drive train. I will have the weight of this engine shortly.

John Roncallo

[QUOTE=Roncallo;1397218

.... however it has been my observation over the years that MB uses a bigger horse.


[/QUOTE]

What do you mean by saying it? There are more horses than the factory says? ..or.?

good luck with the project, I hope you take a lot of pictures.
:)

yes.

i never heard that before, but i will say this....my 185 hp rated with 250 torque 500sec weighs 3650# and it will scoot pretty well!

i have beaten much newer vettes at the autocross. but the driver may not have been as experienced as i am.

tom w

Good points all. The LS7 is "only" $13K now, I got my wiring harness for $500, the custom tuning in the PCM was $350, and had a custom heavy duty 4L60E 4-speed automatic built for $1500. My engine was used (~5K miles) and didn't have most of the auxiliaries but it cost $6000 ("friend price" for a built up engine). A crate LS6 is around $7500. Yours will cost less, mine will have more HP, yours still say's Mercedes on it. FYI, I'm thinking of getting a set of blank engine covers and have "Mercedes" added to them, just to confuse the uninitiated. Gonna be fun for the both of us.

I already put a rebuilt 3.07 limited slip differential in there, so, with fingers crossed, I should be fine as long as I don't put on too wide rear tires and just let them spin.

3.07 LSD ? where did you get one? I mean from which car? Or is it a full custom?

Full custom from Barry Taylor Enterprises in Richmond, CA.

It has just been my observation that cars of equal weight and advertised power from USA and Germany are not so equal in performance. I have always found the German cars to have more performance. So I would really like to see a stock LS7 vs a stock M-120 in equal weight cars. It may not beat it but you may find the 120HP advantage to be somewhat questionable.

John Roncallo