SL engine transplant. Is that possible?

[tdoriot]

I'd guess most SL pilots don't give a rats ass about rather or not the car gets 12 or 20. We usually don't put more than a thousand or two miles a year on them. I put 20 k on a 107 in 30 years! I put lots less than a thousand on the 600 this year. I cant imagine going thru all that work and money for less power regardless of the mileage. Not to mention the whole resale question. The exception might be the M120 V-12 like Roncallo pulled off! Id be up for that until I saw Joahn draped like a Xmas tree with wiring and computers ! That to me is the mystical part of that conversion !

[Strife]

I wonder how many people won't drive their cars much because of the 12-14 MPG of the early 450's, for example, largely hampered by three-speed transmissions and 1970's-style (i.e., very inefficient) engine management.

I have two SL's, one to drive, and one to "keep". Doing a partial rebuild of the engine and a full rebuild of a tranny for the 380 is going to cost me $2000 in parts alone, and this doesn't include a great deal of sweat equity and tools. I figure that a full, professional rebuild of both (including the bottom end of the engine) would be about 7-8K. For that kind of money, I'd gladly pay $1500 for a kit that would let me put a dirtball GM engine in the car (a la John's Cars with Jaguars) and get MUCH better gas mileage and less expensive, parts-anywhere horsepower. There are always and will always be good numbers of low-mileage GM drivetrains around from totalled cars and trucks.

The hot-rod/restoration community doesn't seem to have a problem with modified "classic" cars, as judged by what people are willing to pay for them. Ordinary, US W107s are NOT RARE; it shouldn't be a "crime" to modify a driver-quality car.

I will say again, that the 107 is so narrow, that modern, four-valve heads of ANY V6 or V8 are going to be very tough to fit because of the sheer size and width of the heads; that may narrow the possibilities quite a bit. OTOH, there are modern 4-cyl engines that easily deliver more HP (and even torque!) than the US 380SL did while giving astounding gas mileage in modern, goodie and safety-laden, 3500 pound cars.

[CA-280SL]

What about smog issues. I would think that replacing engines in a Benz could possibly create a smog nightmare. (unless u are in a state that don't require a smog cert )

[mach4]

Originally Posted by CA-280SL

What about smog issues. I would think that replacing engines in a Benz could possibly create a smog nightmare. (unless u are in a state that don't require a smog cert )

In California, of all places, it's remarkably easy. From my build thread...

Originally Posted by mach4

Had my vehicle inspection with the BAR Referee (Bureau of Automotive Repair) this morning. This is the state entity that does the certification that the swap meets all the appropriate requirements. The next step is just the formality of taking the paperwork down to the DMV to get the title changed from gas to diesel.

The process took all of 30 minutes, with 27 of that being paperwork. The major comments were "that's sure a quiet diesel", "sounds like a diesel, looks like a diesel, smells like a diesel... I guess it's a diesel" and "that sure is a big oil cooler". The only questions I was asked was what were the years of the car and donor and what was the size of the engine.

For everything I was prepared for, it turned out to be painless, simple and quick.

And the most amazing thing was - there was no fee. Imagine, a real, true free government service... in California.

Anyway, on to Phase II, getting everything cleaned up and the basics done on the engine - valve adjustment, diesel purge, pop test injectors, compression check, real air cleaner, air conditioner and some interior stuff like tunes, correct tach, boost gauge etc. Oh, and fix my bad ball joint and refinish the wheels.

I'm looking forward to a fun summer cruising around with the top down enjoying a fine Mercedes car.

It's been a long and interesting journey with a successful conclusion.

...and already thinking of the next project.

Registration on my 380SL with the OM617

[97 SL320]

On the motor swap front, I'd be real tempted to use a 3800 GM supercharged ( Buick 3.8L / 231 V6 ) from a front drive car and some bits from a 3800 normally aspirated rear drive Camaro. The heads on these engines were modified on the exhaust side so the manifolds are barely wider then the block.

These normal and superchargd motors have piles of low end torque.

[mach4]

Originally Posted by 97 SL320

On the motor swap front, I'd be real tempted to use a 3800 GM supercharged ( Buick 3.8L / 231 V6 ) from a front drive car and some bits from a 3800 normally aspirated rear drive Camaro. The heads on these engines were modified on the exhaust side so the manifolds are barely wider then the block.

These normal and superchargd motors have piles of low end torque.

One of the big problems with doing a swap in a 107 is the subframe design of the car. The main structural component of the subframe sits right where most of the sumps sit on most engines. You're either looking at major surgery on the subframe or building a sump from scratch (provided your oil pump/pickup will allow) Another problem is the tunnel which is quite narrow creating potential transmission clearance problems. Another problem is the position of the upper control arm mounts. On my swap I had to abandon the A/C compressor on the 617 because of clearance (even the Sanden won't fit). The steering gear tends to be in a bad position for a lot of engines as well.

I know some guys have swapped in Mustang rack and pinion front ends but that is a whole lot of work as well.

These are the reasons you don't see any "kits" to swap in a small block Chevy or an LS engine in these cars.

A quick look at the Buick engine makes me believe that this would be a very difficult swap... then again, when I embarked on my project to put the 617 in a 107 the consensus was that it wouldn't fit without a hood scoop, it would be too heavy, it would be too hard, don't even bother trying.

Fact is, it fits... and it's as close to a bolt in as it gets.

If you do the Buick swap, document the process so others can learn from the experience.

[Strife]

Originally Posted by 97 SL320

On the motor swap front, I'd be real tempted to use a 3800 GM supercharged ( Buick 3.8L / 231 V6 ) from a front drive car and some bits from a 3800 normally aspirated rear drive Camaro. The heads on these engines were modified on the exhaust side so the manifolds are barely wider then the block.

These normal and supercharged motors have piles of low end torque.

This is an underrated engine. The SC models were amazingly powerful, low-maintenance, and gave really good gas mileage in that era in fairly large cars. I have two M90 blowers from them that someday I hope to fit to an M116.

[irshmerc]

Hi, how you doing

Not many fella's would use the words power and 107 in the same sentence, each to his own i suppose.

I'd drop a diesel in the front of mine in a heart beat, petrol is about 9.5USD here, again if i was only doing 20k in 30 years that'd be fine, but i thought the idea was to drive the shagger, and to date at a rough calculation i'm in for 4-5k in fuel in 5 years.

I think whatever engine is in the front makes little difference to the appearence of the car, and lets face it nobody brought a bog standard 107 for power or speed, just that they look the dogs bollocks.

Now... the one advantage i have over most of you(gas milage wise) is that my car gets lighter everyday and on a real quiet night you can here it rusting away peacefully in the garden.

Good luck
Happy new year to you all.

[meltedpanda]

Originally Posted by irshmerc

lets face it nobody brought a bog standard 107 for power or speed, just that they look the dogs bollocks.

i understand the rest but could you traslate that for us americans lol love it !

[DieselPaul]

Originally Posted by Strife

This is an underrated engine. The SC models were amazingly powerful, low-maintenance, and gave really good gas mileage in that era in fairly large cars. I have two M90 blowers from them that someday I hope to fit to an M116.

I have a 1999 3800 Supercharged swapped into a 1987 Pontiac Fiero.

It is a great motor, makes a lot of power. In a fiero they consistently return over 30mpg. My best fill up to fill up was 38mpg, but I don't know that that's accurate. But it was a purely highway trip and I didn't go over 65, so maybe. Either way, the MPG is really good. And chipped and tweaked in a 2,700 lb car, it moves REALLY well.

[DieselPaul]

Originally Posted by meltedpanda

i understand the rest but could you traslate that for us americans lol love it !

Bog standard means base model afaik

But we didn't get 280SLs with fabric interior here. But a Euro M110 will probably give a US 4.5L a run for its money.

[97 SL320]

Originally Posted by mach4

One of the big problems with doing a swap in a 107 is the subframe design of the car. The main structural component of the subframe sits right where most of the sumps sit on most engines. You're either looking at major surgery on the subframe or building a sump from scratch (provided your oil pump/pickup will allow)

That is a non issue with the Buick motors. The 3800 is based on the 231 and that is based on the V8 that goes back to the mid 60's. ( and as a tangent also related to the mid 60's 215ish aluminum V8 that Rover bought.. )

The older Buick motors have the oil pump and filter sticking out of the front cover. The 3800 has the pump coaxialy mounted to the crank snout. Making a custom oil pick up / pan is trivial as the pan surface is flat not rounded on the ends like other domestic engines. At least some of these engines came with a steel pan, anyone with a mig welder and some sheet metal can modify the stock pan.

It would be only slightly more work to add a single stage dry sump while retaining the stock pump for pressure.

Also , most modern engines have coaxial pumps, since distributors have disappeared this is the best way to drive the pump.

Originally Posted by mach4

Another problem is the tunnel which is quite narrow creating potential transmission clearance problems.

A GM 200R4 4 speed automatic would do just fine and is quite narrow. Even a 700R4 is pretty narrow.

On the manual trans front, The T5 T56 that I believe comes in Camaros / S 10 trucks ( not sure if the 3800 got a MT or not ) is narrow and has an integrated internal shifter.

Originally Posted by mach4

Another problem is the position of the upper control arm mounts. On my swap I had to abandon the A/C compressor on the 617 because of clearance (even the Sanden won't fit). The steering gear tends to be in a bad position for a lot of engines as well.

The 3800 was stuffed in some pretty shallow spaces in GM front drive cars.

Originally Posted by mach4

If you do the Buick swap, document the process so others can learn from the experience.

But then I'd have to buy a R107 , I have a ratty 91 300 SL R129 awaiting some sort of silliness. . .

[97 SL320]

Another bit to add. The exhaust manifolds on many of the 3800 motors are tubular stainless that cuts and welds up very easily.

[mach4]

97 SL320:

The issues I was pointing out, were the ones I came across in doing my research. Not being familiar with the Buick engines I couldn't comment specifically. It sounds like you've thought through things pretty well and have the fitment issues pretty well sorted out.

That leaves the smog issue. In CA an engine must be from the same year or newer and must have all the smog equipment installed and functional that came with the engine being swapped in. The beauty of going diesel is that they are exempt from smog (before 1998) so not anything to worry about once it's done.

It would definitely be an interesting swap.

[DieselPaul]

There are a handful of oil filter mounting blocks for the 3800 motor. There are also multiple oil pans.

The 3800NA was offered with a T5 in the camaro. I've seen people L67 swap Camaros, however the throttle body points straight backwards when an L67 is mounted longitudinally. On a camaro people usually make a J pipe to relocate the throttle body, but it still requires some cowl hacking.


The Holden RWD sedans were offered with 3800s so some solutions exist there but you'd have to import some parts.


The stock 97+ ODB2 ECU is very well cracked. The 96 is proprietary and people don't use it. On fieros people usually ran 3800 series 2, the 96+ L67 with a 3800 series 1 obd1 ECU because the obd1 ecus didn't control the trans so it was easier to manual swap with an OBD1 ECU. However at this point I believe the OBD2 ECU has been cracked to the point that you can run an OBD2 ECU and they can just code out all the transmission functions.

My car runs the 1999 L67 3800SC-2 and the 4T65E-HD so I run the OBD2 ECU.

I've seen CARB legal 3800SC swaps but I don't know how they are getting manual cars certified since the supercharged motor never came from the factory with a manual.

I used Ryan Gick at Sinsiter performance, his ECU reflash is/was $85 and he is a huge wealth of knowledge.