Interesting hot rod project idea - Mercedes Meets Nissan

[Oldfisti]

I like yours the best. 

[NAKID]

She's a bit nipply in that pic...

[lethe]

74 280C isn't worth a lot. Ours (72 W114 with 2.8L twin carb) is worth MAYBE 7K, if someone were willing to pay that (not many are), and it's considered more collectible than the later models (probably because it is prettier). We've invested over 15K in restoration. In other words, we will be keeping it for a while. We paid 1500 for it originally, and that was probably too much.

Not sure if it has flex discs. I swapped out the driveshaft years ago and I don't recall anything other than a beefy driveshaft on U-joints. I may be wrong. The axles are pretty spindly though, just a thin steel rod on CV joints. They will probably the weak point.

The Q tranny is auto, unfortunately. It's also a mediocre design, if we had unlimited funds I would have it rebuilt with stronger internals, new valving and a performance torque converter. Nissan never made a manual that fit the VH45 (the only car it was ever put into was the Q/President) so that option is out.

It doesn't have anything in common with stuff like the FX45, M(?)45 or Titan engine? Although, I'm not even sure any of those are manual either.

[NeufUnSix]

The VH45DE was a unique design found only in the early Qs, later "4.5" models were completely different. Cost saving was put into effect in the mid 90s and the more recent engines are built to a price. The VH45DE was a cost-no-object V8 at the time, with polished internals, heavy duty rods and crank, sodium filled valves, variable valve timing, and all sorts of goodies. People who have rebuilt them say it's like opening a race motor. They are pretty durable, but they had one fatal flaw - plastic timing chain guides that would disintegrate. Mine has already had the guides and timing chain replaced; aside from that it is original with 250 000 kms and it still runs damn strong with zero oil consumption.

[Monsterlover]

Great project and a big +1 to all the

If you're converting to fuel injection, don't forget the fuel system.  You'll need to add a return line (or use the existing supply line as a return), properly sized supply line (with filter) and a pump.  If it were me, Id pull the pump/sender unit from the donor and figure out how to graft it onto your existing fuel tank- top mount style.

You'll for sure need the ECU, TCU and all the associated wiring but that's all plug and play.  A wiring diagram for the donor will be worth it to procure.

If you have a big engine bay, can you use the nissan radiator in the Merc?  That's the easy way out if it fits, as far as cooling the motor goes.

Exhaust shouldn't be too hard.

Keep the original drive shaft.  Once the engine and trans are in you can measure for your custom one.  They can chop both shafts and put the Nissan front with the Merc rear section.

Cool idea

[NeufUnSix]

I think we could use the Nissan rad, maybe. The engine bay is spacious, to say the least. It fits a big straight six with about 8 inches free space at the front and a good two feet of open air on either side. It would certainly make things easier, with regards to coolant sensors in the rad.

Fortunately I have a complete shop manual for the Q so sorting the wiring will be simple. It even details how to remove the engine and transmission properly, which will come in handy. I just need to figure out what needs to be bypassed. Keeping it simple is the goal, so if it is not needed to run the engine and transmission, it won't be tranferred.

I'm a little worried about the fuel pump assembly; the Q uses an upright tank (mounted behind the rear seats) with the pump inside the tank, bolted in from the top. It's cooled by being submerged in the gas, so using it externally it not possible (it's probably a flat pickup too, as opposed to a tube pickup). But it might be too tall to fit into the Mercedes tank. Does anyone know of an aftermarket fuel pump that can be mounted externally? I've seen it done but I have no clue what to chose, or what kind of flow rates I'd need.

Here's a question for hot rodders - the Q uses an independent suspension of some kind, while the Mercedes uses a swing axle at the rear. How much trouble would it be to move the Q diff and axles into the Mercedes? Would it screw up the suspension geometry? Can some sort of hybrid (Q diff, Merc axles) be fabricated easily?

[Duck-Stew]

My $.02 & experience:  Using an external pump will be noisy.  The submerged pumps run quieter and cooler too.  Figure out the psi and flow needed to run the Q45 motor and just find a cheap pump from another car with a similar tank as the 'Cedes.  Buy the other tank and take them both (other car and the 'Cedes) to a competant welding shop to have the other cars fuel pump flange mated to the 'Cedes tank.  All the wiring the fuel pump needs is a fused, switched on 12V power source and a ground and it's happy.  No need to try and make the Q pump work if it's going to be a nightmare.

Also, figure out if the TCM and ECM talk to each other.  If they don't (transmission control module completely seperate of the engine control module) it may be possible to have a different transmission adapted to the ass-end of the Q45 motor (I know at this point I'm sounding like I'm made of money but I'm just offering options...) and therefore it may solve problems like space/torque capacity/# of gears/etc...

Oh, and Derby?!?  I never said smokin' the tires was a bad thing!!!!

I think we could use the Nissan rad, maybe. The engine bay is spacious, to say the least. It fits a big straight six with about 8 inches free space at the front and a good two feet of open air on either side. It would certainly make things easier, with regards to coolant sensors in the rad.

Fortunately I have a complete shop manual for the Q so sorting the wiring will be simple. It even details how to remove the engine and transmission properly, which will come in handy. I just need to figure out what needs to be bypassed. Keeping it simple is the goal, so if it is not needed to run the engine and transmission, it won't be tranferred.

I'm a little worried about the fuel pump assembly; the Q uses an upright tank (mounted behind the rear seats) with the pump inside the tank, bolted in from the top. It's cooled by being submerged in the gas, so using it externally it not possible (it's probably a flat pickup too, as opposed to a tube pickup). But it might be too tall to fit into the Mercedes tank. Does anyone know of an aftermarket fuel pump that can be mounted externally? I've seen it done but I have no clue what to chose, or what kind of flow rates I'd need.

Here's a question for hot rodders - the Q uses an independent suspension of some kind, while the Mercedes uses a swing axle at the rear. How much trouble would it be to move the Q diff and axles into the Mercedes? Would it screw up the suspension geometry? Can some sort of hybrid (Q diff, Merc axles) be fabricated easily?