benzamino fuel tank relocation help - PeachParts Mercedes-Benz Forum

dark hawk · #1 10-06-2015, 01:05 AM

soooooooooooooo, I am building a ghetto has all hell benzamino (w123 sedan to pickup conversion.) I have seen quite a few people build these and even the really crappy ones have a flat bed with the fuel tank concealed somewhat decently (the factory tank location is between the seats and the trunk vertically.)

So how do you guys suggest I hide/put this tank? I took a look at the fuel line under the tank and the wire (I am assuming fuel pump) in the top of the tank and they both appear to have very little slack. Therefore I do not have much room to move this tank WITHOUT modification.

Am I wrong? Is there more slack than what there appears to be from the factory wires, or are there other options? Or should I cut the wires going to the fuel tank and solder additional ones in to extend there length and then rotate the fuel tank 90 degrees ccw? The latter seems to be the best option but idk.

Thanks, any comments (including negative ones) are appreciated

Rogviler · #2 10-06-2015, 01:24 AM

I would say if extending a couple wires and fuel lines sounds high on the difficulty meter, I might rethink the project... (That may just be the way I'm reading your post.)

Beyond that I would personally look into a wagon tank or just get an aftermarket racing-style aluminum tank made to be installed on a truck. I don't know what the sedan tanks look like, I'm realizing, so they may or may not be able to be mounted flat. Either way it should definitely go under the bed. I suppose another direction to go would be behind the seats like some pickups.

I'm all for it though, I think they look good when done correctly.

-Rog

mannys9130 · #3 10-06-2015, 01:45 AM

Why not put it in the same relative configuration but behind the front seats? Instead of the back wall if the bed being right against the seats, put the tank in between.

mach4 · #4 10-06-2015, 01:59 AM

Just something to think about....

The roof on a 123 is a structural member. When you cut that away, as in making a convertible, or in your case a pick up, you're significantly weakening the structure. Stories abound of people cutting the top off their car to make a convertible only to have them collapse in the middle. The 123 is a unibody (frameless) design where the body itself is the "frame". Cars like my 107 roadster use a beefed up tunnel and side rails to provide the structural integrity to go topless.

I'd be more concerned with this quite critical aspect of the project as opposed to the more trivial fuel tank positioning. Fuel tanks can be welded up out of aluminum quite easily, or even fabbed up using epoxy and fiberglass, in most any shape available. (I made a fiberglass aux tank to fit the spare tire well on my diesel SL but in the end decided a spare tire was more important than 1000 mi legs.)

There is no fuel pump at the tank on a 123. It uses a lift pump on the side of the injector pump to draw fuel from the tank under vacuum. The wires you see are for the fuel sender for the fuel gauge.

You should really consider starting with a wagon - that way you've already got the tail gate and the flat fuel tank. An order of magnitude easier I think. And the SLS as well for carrying a load.

m1tch · #5 10-06-2015, 02:33 AM

Perhaps research into how the aftermarket coachbuilt W210 pickups are made?

t walgamuth · #6 10-06-2015, 06:14 AM

We used the wagon tank in my 39 Studie. It was nearly a bolt in job.

dark hawk · #7 10-06-2015, 11:52 AM

So to clarify some stuff. This isn't really a serious build. This is a beater car that I really like but couldn't really sell it for any more than scrap value so some attention to detail will be abandoned. The reason I want it, other than for fun, is to hall around my dirt bike and do other pickup bed type stuff with it.

Also, would it be effective to reinforce the unibody with a vertical (light/roll bar looking) or horizontal crossmember? I'm an experienced welder so the fab shouldn't be much of a problem.

My fuel gauge is broken due to a shabby wiring job in the dash by the previous owner, so now that I know that the wires to the tank are only for the sender I think I'll just cut them and rotate the tank and have it exposed on the bed.

Thanks for the help. Appreciate it. Feel free to add anything or make comments on what you think. Thanks

mach4 · #8 10-06-2015, 12:23 PM

Anything you can do to add metal to the unibody would help. A roll bar type reinforcement where you've got triangulation fore and aft would really help. Also welding the rear doors. If you welded inner panels to the outer body panels in the bed it would create a kind of holow "beam" structure that would help too.

Good luck with the project.

cooljjay · #9 10-06-2015, 02:11 PM

Why don't you just transfer the driveline into a pickup truck?

You'll pretty much need to create a whole subframe, to sit the body of the car on....

This is like throwing money into a fireplace, the time and money need to properly create a pickup truck out of a sedan is sooooo null n void.....again I would just transfer the OM617 into a beater pickup....

dark hawk · #10 10-06-2015, 04:27 PM

Why don't I put the om617 in a pickup? Because I'm stoooopid duhhhhhhh.

All kidding aside there are more than one, I looked into om617 swaps and though it might not be difficult for some it is out of my league of mechanical expertise. Second of all even if I did have the skills I don't have the space for another car nor the willingness to buy the tools needed.

As for the the it being like throwing money into a fireplace, it shouldn't be. This is not going to be expensive. I already have the tools I need and plenty of steel laying around from fab work from other stuff. The car itself is a $h1tb0x beater and isn't worth anything.

above all though this is really just for fun, laughs with friends, ect. This is not meant or going to be clean. Just silly but functional lol.

cooljjay · #11 10-06-2015, 05:10 PM

Quote:

Originally Posted by dark hawk

though it might not be difficult for some it is out of my league of mechanical expertise.

Well for your safety and everyone else's on the road.....I don't recommend trying to hack apart a w123 and trying to make a pickup....When you don't even have mechanical expertise to transplant an engine....

As was said, this takes a LOT more knowledge then just tack welding on random fence posts laying around the yard...

Why not just get the mechanical expertise to fix up this "beater"....And drive a car that was designed way ahead of its time....That will both keep you and others safe on the road....I know totally wacky idea...

dark hawk · #12 10-06-2015, 06:13 PM

The main reason I'm not so concerned is that after looking into this there have been other people who have done it without much issue at all.

As for doing a swap, the hard part for wouldn't be bulling the motor out of the car. Or even putting it in a compatible vehicle. It would be putting it in a truck that had never intended for it and making it all work. Gauges, wiring ect that detters me.

86_MR2 · #13 10-06-2015, 06:20 PM

So im a big van of the elcamino-conversion but i dont think id do it to a w123, that being said id go for a wagon tank and what someone said above is correct, if fabbing a gas tank and running lines is a concern maybe you should go get an actual elcamino and toss your om617 into it, this would most likely easier (but then again idk). I ve always wanted to do this to a mkiv jetta tdi wagon, or similar era passat wagon with vr6 and 4-motion, now that would be awesome. Another one that always came to mind but isnt something i d be interested in working on is an e38 740il, v8, rwd, and huge. The e38 would look really nice as a pickup too (imho) keep that trunk line and rear lights and make it fold down like a normal tailgate. Basically just cut it where it turns horizontal or an inch back to give your trunk depth then you would only need to fab the inside face of the tailgate.

p.s. even though its a beater dont hack it when you cut it or you ll kick yourself later when the lines dont look good. measure it a ton, get happy with how it ll look and then cut it with some patience. If it were me i would make my line by rolling down the rear window, going to the top front(of car) side and connecting straigh across to this point on the opposite side. then you just cut straight from the bottom of the window around the rest of the car. It ll look better than a flatbed and maybe you can use the rear glass to do your rear window. It d be very easy to make that line look symmetrical too. You kinda need to leave the doors on it and weld them in order to keep some rigidity in the structure. Trucks can have flatbeds but they re also ladder framed.

t walgamuth · #14 10-06-2015, 07:54 PM

If you proceed with this remember that the drivers seat extends pretty far behind the door post.

hockeyboysomers · #15 10-06-2015, 09:19 PM

I can't comment on the wisdom of turning a 123 into a el camino. Regarding the tank, Greasecar makes a tire shaped tank that fits right into the spare tire well. It is readily available for sale on their web-site.