W108 - Bouncing some project ideas around - Page 2 - PeachParts Mercedes-Benz Forum

Tony H · #16 12-16-2014, 10:16 PM

If you are looking for more power your biggest bang for the buck would be a 560 V8 and transmission-I doubt there are many cost effective mods you could do the the 6 cyl. You are embarking on a long process(don't ask me how I know) and if you are not attached to a manual trans a 560 engine+trans would be the ticket. You might want to buy an engine from a driving car or a guarentee since the aluminum engines suffer blown head gaskets and striped head studs if overheated. You will also need to consider a 3.27 rear axle to lower your RPM with the larger engine.
I think the 560SL exhaust manifolds will fit the chassis and give a true dual exhaust.

Tomguy · #17 12-17-2014, 07:05 PM

Quote:

Originally Posted by mosu

Reading, reading, reading, I have settled on a game plan. I will refresh my existing setup. I want to stretch the budget as much as possible since I won't be doing most of the work.

2) Fuel delivery will stay carbed for now. The Zeniths are missing some pieces such as the anti-stall diaphragm and are in generally poor condition. I'm leaning towards a set of Webers, but can't seem to find consensus in past threads if they are a definitive win over the Zeniths or an improvement because someone's setup was worn. Any final words?

The thing with this is that honestly, by the time you're done with a carb rebuild, an engine reseal (and likely a rebuild of at least the top end), and any performance work on the engine (which wouldn't be much you can really do to it) you can buy a good running 560 engine & trans and pop them in. It'd likely cost under $500 for the 560 combo from a good running donor (and say another $500 or so to do the timing chain, rails, and valve seals for sanity measures). This is assuming you get a good compression low-leak (or leak free) donor engine. Worst case would be if Toronto is like NEPA, you can buy an entire 560SEL in good running shape for $1500. That would give you the engine, trans, all ancillaries for the engine & trans, and then you can part the rest out or scrap it.

Remember, to do the engine resealing, it's gotta come out anyway, so you're only paying someone else extra labor for someone else to pull the engine/trans for the 560 if you went the parts car route.

AramSL · #18 12-17-2014, 10:41 PM

I vote for a fuel injected M129/130 engine. The main point of emphasis here is good ol' rock solid mechanical fuel injection. The V8 4.5/3.5, stay away. Not worth getting mired in electrical issues, and some of the bits for that early electronic FI system are very very pricey and difficult to get right. The M130 with fuel injection typically only has one temperamental part: the cold start valve located on the intake manifold. Other than that, it's very straight forward, and is simple to tune and adjust. One of my all time favorite mercedes engines...with the M110 being my least favorite.

mosu · #19 12-19-2014, 06:19 AM

Interesting that you dislike the M110 - I loved that engine. Such smooth power and nice sound. Easy to work with as well.

I'd love to do the bigger motor swap from a parts car. Up here it's not economical (a crappy mid-80s 560 is ~3k).

Converting from a carbed to FI M130 requires a new fuel pump, some electronics and wire harness changes and adding a new fuel pump, correct?

Another idea I've been toying with was to Megasquirt this car down the line. Read that someone had good results on a W115 with the GM throttle body injection. If the M130 had port fuel injection (i believe that DJet was port), I'd love to try to 'squirt it down the line and see how it behaves.

Tomguy · #20 12-19-2014, 02:33 PM

That's a shame when you consider what ~$3k is here in my area.
1987 Mercedes Benz 560 SEC

Mega-squirting an M110 would be worthwhile, I am unsure about an M130. The W115 that was squirted was almost surely the M110. I've seen a few posts from users who have done it.

mosu · #21 12-19-2014, 03:42 PM

Yea, the market is completely different.

The posts I've seen regarding the squirting were for the 4 cylinder model IIRC. Don't quote me on that.

I think I'll head down the path of stretching out my current setup while I clean up the body and interior. I'll try the MegaSquirt next summer and see if improves things to the level of a factory injected model. Will be a fun project and if it works out I can have a DIY for others to follow.