1974 SEL, Rebuild or Replace engine - Mercedes-Benz Forum

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post #1 of 3 (permalink) Old 09-25-2015, 05:45 PM Thread Starter
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Date registered: Sep 2015
Vehicle: 1974 450SEL
Location: Kona, Hawaii
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1974 SEL, Rebuild or Replace engine

Hello all,

I recently received a sight unseen 1974 450 sel. Unfortunately the driver's side exhaust manifold is cracked and the engine is running on 7 cylinders. I know which cylinder is bad, and I can see the spark arcing when I remove the wire. I have yet to replace the spark plug or do a compression test. Those will be done next, but I'm researching my options if it's not an easy fix.

I'd most like to fix/rebuild original engine, but have seen posts on here talking about dropping $5K easily.

I've found a 1977 560 SL on my island with 99k miles for $1800. Will this engine fit in my car?

Also, the car came with 5 real knock off wire wheels. The seller called them Zeniths. I have included a picture of them. Are they desirable? I prefer the Bundt myself.

A thousand thanks for all responses. I'm hoping my Mercedes ownership will get less rocky moving forward.

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post #2 of 3 (permalink) Old 09-25-2015, 07:42 PM
w108,107 Parts Hoarder
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Date registered: Jun 2010
Vehicle: 4Keep:450slc5.0cab 280sl5sp 280se4.5 500seAMG 2sell:500sl92 380se83 300se86 350sl4sp 75slc MorInSig
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Usually it's not too hard to figure out why a cinder isn't firing. It sounds like it's a spark issue. Cap, rotor, plug wires, spark plug. I guess it could be distributor wobble, but that would be rare.

You've got a d-jetronic and the 107 (SL roadster) forum has a lot of knowledgeable guys there that can help with a d-jet. Fuel, air, and spark are what you need. If it's not spark (mentioned above) it could be fuel, and if it's only one cylinder , it's probably a simple fix since the ECU and trigger points would both affect more than one cylinder.

Most likely you are looking at an easy fix there.

The deal on the 560sl sounds like a good one, and if you've got the space, it might not be a bad thing just to snag, but virtually none of the parts are common between the two vehicles. I don't know if the exhaust manifolds for the 116 and 107 are the same, but I've got two pairs of 72-73 r/c107 manifolds I'm looking to sell, and I'm certainly not the only guy parting out 107s.

If I were you, I'd probably go the easy route and fix the existing engine. The 560 engine is a whole different and more complicated animal in my opinion.


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Click for list of my 34 MB since 2010. If, you want 70's-80's Mercedes tuner wheels, let me know.
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post #3 of 3 (permalink) Old 09-26-2015, 04:53 PM Thread Starter
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Date registered: Sep 2015
Vehicle: 1974 450SEL
Location: Kona, Hawaii
Posts: 2
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(Thread Starter)
Thanks for the reply.

Well it turns out it was just a spark plug. Good news for sure.

Now on to the cracked manifold and interior.

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