Date registered: Dec 2014
Vehicle: 1991 560SEC
Location: Woodinville, WA
Mentioned: 3 Post(s)
Quoted: 166 Post(s)
Crazy idea. Gen 1 500 into Gen 2 420.
Ok work this through with me. Right now, I have an extra US 500 motor from my euro motor swap project. it's a good running motor, pretty clean (needs typical chains/guides but not urgent)
Meanwhile, I have an excellent running Gen2 420SEL that I've been contemplating doing a motor swap to a 560.
SO here's my question (it's twofold)
First, what's the HP difference between an early US 500 motor and a Gen 2 420 motor. Is there an appreciable difference in performance?
Second, is this swap even possible? Just thinking it through, the only two components that distinguish Gen1 from Gen2 is the ignition distributor and the fuel distributor. Both physically fit on the Gen 1 Motor.
So I'm thinking (again, not in detail) that the only things required to put a Gen1 motor in a Gen2 car is to use the Gen2 fuel distributor (Direct swap) and the ignition distributor, and use the Gen2 electronics.
All of the sensors should be in the same location. I know the water pump configurations but the inlet and outlets are in the same place (no problem). Exhaust should swap over (no problem). The crossover hoses for the injectors are different because the fuel distributor is different shape on the base (no problem). Motor mounts and transmission bolt patterns are exactly the same (no problem).
So physically the motors are the same. There are probably more subtle differences in the intake manifold then I am expecting, but I'm thinking it would be super easy to use the Gen2 420 intake if there are too many other differences.
At first glance this should be a straightforward swap. What am I missing? Is there any reason this is more difficult then I am thinking?
1991 560 SEC Euro
1986 420 SEL
1985 500 SEC (US)
1983 500 SEC (Euro)