Project Advice Needed: My W116 - PeachParts Mercedes-Benz Forum

chinny4290 · #1 02-02-2010, 12:48 AM

It's funny...I lose so much sleep over what I can/should/want to do with my 280S.

it's been sitting for several months due to needing a full brake overhaul.

This summer, i am damn sure since I am taking a semester off and working and saving that I want to take the engine out and repaint the whole car.

But that had me thinking...The US M110 carbed which is what I have is terrible...sounds great, but terrible. Abysmal fuel economy, no power, and the headache of consistently worrying about a carb and its tuning. It came with the territory granted, but I would probably be in a much worse situation with either the M116 or M117 from a 350 or 450.

Since I am pretty firm about removing the M110 from my 280S for body work purposes...I am sure I can find a decent M103 from the late 1980s 300 models (300E, 300CE, 300SE) to replace that M110. That would make the car much faster, and have much better fuel economy leaving it to be far more DDable which is what I want.

I originally wanted to convert it to Fuel Injected...but that sounds like a PITA.

I'm sure I want to keep it a 6cyl to keep the agility that I have with the smaller engine. What i can also do is transplant a FI M110 but 280 W116s are nearly impossible to come by here in the states.

Another thing is that my engine only has 90k miles on it. It has so much more to go but I dont think i can continue driving the 400k miles of life it has with the fuel economy and power it has

and the 280Ss here in the states are a needle in a haystack...so I already have low use and rarity along my sides. I'm also seeing that W116s, especially in good condition are slowly appreciating...albeit slowly. This is a long term project so this is good.

I want to DD this car but if I really want to be happy I want to put a better engine in it or make the engine better.

However, what's stopping me is the fact that it's rare, and has low miles and will probably be worth more when I finish working on it. And modding it will depreciate the value.

What do you guys think I should do? I also consider how rare W116s are period in the world, and I feel modding this one would be making it 1 less genuine W116 in the land.

rs899 · #2 02-02-2010, 01:53 PM

Have you considered converting it to a Weber progressive carb, maybe a 32/36 DGV? (if that one fits). Might help fuel economy a bit. I doubt changing the engine is going to help much more (unless you are thinking OM617). The basic problem is weight....

CIS now has got to be very expensive and problematic to keep in good nick.
Webers are very reliable and would suit daily driving very well. You may find it hard to believe, but 99% of all gassers until the mid 70's had carbs and ran just fine.

On the other hand, here's someone who tried it and didn't like it...

weber carb conversion kit

JiveTurkey · #3 02-02-2010, 03:49 PM

Usually if you're really concerned about "future value" it means that you're going to want to sell the car at some point. If thats the case then it's usually much easier to sell a car that still has it's original engine, especially one with only 90,000 on the clock. If you plan on keeping the car until you're worm food (IE me with my 114) then the only person's opinion that matters is your own.

Muscle Car guys usually take that advice to the extremes, they'll have a car that they basically cannot drive because they're afraid of breaking an original part, or they have a car thats so wildly modified it barely resembles anything that ever came down a production line.

With an older Mercedes that was mass produced (like most of ours *shakes fist at 6.3 owners*) you can usually strike a nice balance. For instance, I'm repainting my 250CE in a non-factory color (Bright Silver, but not a shade offered by Mercedes) and swapping the Tobacco Brown interior for a red MB tex interior. I'm never selling the car, so I don't have to worry about pleasing a future owner.

If you plan to eventually sell the car, but still want a fairly easy sale you might want to consider a rebuilt engine (you'd be suprised how good the mileage is when everything is close to factory spec and there aren't 40 years of use showing on every part.) I think www.Adsitco.com sells rebuilt engines. I personally think a Diesel conversion would be *****in' and it would recieve the coveted "JiveTurkey seal of approval."

If you're keeping the car for the rest of your natural days then you're only limited by mechanical ability and budget.

chinny4290 · #4 02-02-2010, 05:29 PM

Quote:

Originally Posted by rs899

Have you considered converting it to a Weber progressive carb, maybe a 32/36 DGV? (if that one fits). Might help fuel economy a bit. I doubt changing the engine is going to help much more (unless you are thinking OM617). The basic problem is weight....

CIS now has got to be very expensive and problematic to keep in good nick.
Webers are very reliable and would suit daily driving very well. You may find it hard to believe, but 99% of all gassers until the mid 70's had carbs and ran just fine.

On the other hand, here's someone who tried it and didn't like it...

weber carb conversion kit

I have considered a new carb but I haven't the slightest clue about carbs.

Some dude on the W116 board switches back and forth from the Solex to a Holley..don't know which one though.

Also..what's set in stone however is at least a custom exhaust and removal of the cat.

I do plan on selling it but not anytime soon because it's going to be a while until i can afford what I really want which is a 450SEL 6.9.

So I wold say I plan on having the car for at least 5 years if not more as a project. And it will be repainted this summer which it needs, full down to the metal.

Also...the engine actually performs decently. I've averaged 17MPG on the highway like the original window sticker said.

JiveTurkey · #5 02-02-2010, 07:20 PM

I hate to say it, but if the engine is in good shape with only 90,000 on the clock then please have some mercy for that poor car and don't alter it significantly. If you're not that thrilled with it sell it now and start saving for what you are really after.

chinny4290 · #6 02-04-2010, 07:07 PM

Quote:

Originally Posted by JiveTurkey

I hate to say it, but if the engine is in good shape with only 90,000 on the clock then please have some mercy for that poor car and don't alter it significantly. If you're not that thrilled with it sell it now and start saving for what you are really after.

I'm leaning towards this too....

wolf_walker · #7 02-04-2010, 09:35 PM

It needs fuel injection, and modern ignition with an advance curve worth a crap.
I'd bet my life there is 20hp and 4mpg on the highway in the M110. I can feel it in my bones. But it ain't happening with a damn solex or any of the other half-assed ill suited carbs out there and not with the slacker smog timing BS they have going on with them.
If I can't talk somebody into buying mine I'm probly going to have to put my money where my mouth is this summer.

That being said, there are a ton of interesting motors that could grace the engine bay, I vote OM617 also, but there are other gassers around that'd work, preferably with there respective fuel and spark control intact and transferred over. No small feat but people do it every day.

Tomguy · #8 02-05-2010, 02:45 PM

The m110 in your car, just like most of these other older engines, suffers lack of HP from "Smog Era" weak cam profiles, low-tech ignition systems, carb or low-tech FI systems, restrictive intakes and exhausts, and inefficient transmissions often without overdrive... All of these factors cost 1MPG each (highway) easily, if not more.

You say you want a 6.9 so it doesn't sound like you care about the fuel economy, it's the power you don't like - either it should have no power and fuel economy, like a diesel or a 4-banger, or it should have power and no fuel economy, like the 3.5 and 4.5 (pre-smog). Your fuel economy is 3.5/4.5 territory in highway driving, but with much less power. Your gas mileage on highway trips is about the same as my '92 Jeep, and worse than my '99 300M (~230HP) and worse than my '06 Charger (~365HP with my mods).

Your options: Buy a newer car to replace this one as a DD, or if you love the w116, start putting money and time into fixing that which is holding it back. A more efficient intake, port and polish the intake manifold and head (intake and exhaust) ports, get headers and a custom exhaust built, throw on a multi-port EFI system like MegaSquirt, put in a Crane or Pertronix ignition system, or maybe have the MegaSquirt control the ignition as well, since it can adjust the spark curve in a more efficient manner than the old-style spring-weighted mechanism in the distributor. Find euro cams and euro heads for the m110. Doing all this will probably add a solid 50HP, and increase your highway MPG to above 20. Find a 4 or 5 speed overdrive trans that will fit in, with a good gear ratio, and you can possibly break 25 highway MPG. Keep in mind that it's a heavy car, with high wind resistance compared to today's sedans, so it won't get 30, but you'll be much happier with what you've got.

wolf_walker · #9 02-05-2010, 06:25 PM

Solid by the book advice. But that is an expensive, hard won 50hp in my opinion. This has kept me from doing anything interesting to mine.

I've seen a few photo's here and there, and I know they modify this motor a lot in europe where it was more common(and sucked less) but I wonder about the merits of a cheap turbo on the thing along with megasquirt? I bet that'd be your 50hp right there with not much boost. Preferably enough to not have an intercooler. It worked for Volvo and Saab.