72 450SL Project Car

[larracfb]

Are there any aftermarket fuel delivery system that could replace factory fuel pumps, pressure regulators, injectors, etc. for a 1972 450SL? Also thinking of replacing ignition system with electronic (no points) system. I don't intend to do any racing. I just want to bring the car to a driveable condition without having to worry much about buying expensive OEM parts. Any advice will be very much appreciated. FBL

[Richard Wooldridge]

Hi there,
It wouldn't be terribly difficult to adapt the GM throttle body injection used on the 4.3L V6's from the '88 - '92 era- you'd need to use the proper fuel pump, I used an external pump on my '82 Mercedes/GM 4.3L V6 project, you'd have to fabricate an adapter to the intake manifold that would mount the throttle body unit, you'd need to install the GM temperature sensor, you'd need to come up with an ignition signal into the GM ECM, install throttle linkage, O2 sensor, etc, etc... but you'd end up with a very driveable engine. But, the other side of the coin is what's wrong with the original setup? It's possible the car would lose value by altering the original injection setup. Of course, the GM throttle body unit would be much easier to troubleshoot if a failure were to occur. (The only problems I've seen have been defective injectors, bad map sensors, defective fuel pumps and failed ignition systems on the GM V6's. The big advantage the throttle body units have is their sheer simplicity.
Let us know what you end up doing!

[larracfb]

Thanks for the input. In reply to your question - "what's wrong with the original set-up?" - maybe nothing except that MB parts are expensive. Fuel pump for this car lists bet $500 to $600! I know that's part of being a Mercedes Benz owner - "if you can afford to buy the car, you should be able to afford to drive the car". But it doesn't have to be expensive. Ending up with a "driveable engine" is what I'm after. It's a well built car and I would like to own something that I can enjoy driving without worrying too much about down times. I also own a 79 MG Midget. I enjoy driving the car but it requires a lot of work to keep it running.

Right now my plan is to, at least, get the car running using it's original FI sytem (get the pump running and clean the entire fuel system) and get it tuned up. If I decide to go with some aftermarket FI system, I'll let you know.

A lot of work ahead of me - the ultimate goal is to restore this car so that it is enjoyable to drive without worrying about too much breakdowns.

fblarracas

[page62]

Why are you paying list prices for parts? Click on the "Buy Parts" link at the top of the page. This forum is hosted by a very good vendor who will save you many, many $$$ on parts!

[kip Foss]

If you want more preformance and cheaper parts and repair costs install a 5 liter Ford engine in your car. You can easily get 50% more hp and 50% less cost this way. I have a Euro 280 slc that had a 5 lit. Ford installed in it. I bought it as a parts car because the installation was not well done but it did show me that the engine fit into the car with a lot of room to spare. The important thing in this conversion, unlike trying to get a 350 sbc in this car, is that the tramsmission goes in with room to spare. The Ford is a front sump engine which also helps. I am hoping to make this swap in my 1977 450slc.

In you are just starting out with MBs you had better prepare youself for some parts counter sticker shock. The price of things like the fuel pump and the fuel distribution unit will stop your heart.

[Boatjockey1]

Hey Guys,

I have a 1985 380 sl that I want to convert to a big block. Was considering 350 chev 365 hp or earlier buick 401 nailhead engine and of course the 502 Chev big block. I do understand the oil sump problems etc. and I believe to Buick has a front sump system as chev has the rear sump. I am more inclined to stick with the big block engines as I want the HP. Anyway I am open for any info you may have in conversions of the sl's to domestic engines. I did take some measurements of the 380 engine versis the 502 today and the size is about the same. But have strongly considered the Buick 401 or 425 ci. because of size. Plan to couple up with a hydro.

Boatjockey1@hotmail.com

[Richard Wooldridge]

Hi there,
One thing to keep in mind is that whatever engine you use, make sure you will end up with a transmission that is narrow enough to fit between the seat rails. For example, the T700R4 is wide pretty far back on the case. When I installed the 4.3L V6 in my '82 300 the transmission clearance was the biggest problem. It wouldn't be much of a trick to put a 350 Chevy V8 in with a T200 auto, I'd think. You will want an overdrive transmission to get some gas mileage, if you are planning to drive it on the road.
My '82 has a 560SL engine in it, and it has PLENTY of power, even though it starts off in 2nd gear.
The chassis is designed to accept the 110 inline six, so there's plenty of length in the engine compartment for most anything you want to install. It is lacking in width at the steering gear area, also lacks starter clearance at the steering idler post. I cut two inches off the front of the pan on my V6 installation - I'd think that you'd have to do the same on a chev V8 installation.
The Merc 560 engine is a nice, reliable, strong engine, just expensive to work on.

[Strife]

Originally Posted by larracfb

Are there any aftermarket fuel delivery system that could replace factory fuel pumps, pressure regulators, injectors, etc. for a 1972 450SL? Also thinking of replacing ignition system with electronic (no points) system. I don't intend to do any racing. I just want to bring the car to a driveable condition without having to worry much about buying expensive OEM parts. Any advice will be very much appreciated. FBL

There is a guy working on a Megasquirt conversion on another board...but I haven't heard anything recently. I really worried about him because he was going to fabricate his fuel rail in aluminum or copper

There are much less expensive aftermarket fuel pumps; the only REALLY expensive parts (I looked into this) are the injectors, the "trigger points" (not the ignition points, the signal for injection) and the electronics. But there is a company that can rebuild the electronics and it really isn't any more expensive than modern parts.

I think a lot of people go electronic on that era of ignition system, and except to a purist (and a wealthy one at that), it isn't a sin.