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2003 Mercedes SL, 1964 Corvette StingRay Sport Coupe, 1992 Mercedes 300 SL, Porsche 911 Twin Turbo
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Discussion Starter #1
Or to say as easy as i can.
What is the most easy way to have the M104 cylinder head on a M103 engine??

Or is it better to swap the M103 engine for a M104 engine?

I suppose that the engine harness must be changed?
 

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Sith Lord
72 280SE 88 560SEC 92 E500 6.0 95 SL320 14 GLK350
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The M104 is a double overhead cam with 4 valves per cylinder - you only have 2.

Different setup.
 

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Discussion Starter #3
I just saw that i have asked that question here before :eek:

Is it a big difference on the engine harness between the M103 and M104 engines?

I am sure the engine mounts and stuff must be the same?
 

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SL's & 500E's
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103?

Or to say as easy as i can.
What is the most easy way to have the M104 cylinder head on a M103 engine??

Or is it better to swap the M103 engine for a M104 engine?

I suppose that the engine harness must be changed?
My USA 92 300CE has a 104, who would have thought Mercedes would put a 104 in an E class, and a 103 in an SL of the same year..strange

I see the 64 vette in your fleet, that would be my fav... must have cost you a bunch

I had a 67 327/350 coupe in medium blue with a white interior when I was young and stupid. ( I sold it to get a 69 coupe..what junk that 69 was)

Wish I had that 67 back...

Back to your question, If I were to consider an engine swap like yours, it would be the 500. My 99 SL500 gets better gas milage than my 92 300CE, and the V8 is a joy to drive. Many 124 coupe owners wish they had the 500 in place of the 104, but too many changes to make, even the engine bay needs modifications. Mercedes should have built a 500CE, oh well just dreaming...

But your 92 SL engine bay is already designed for the 500 v8 why not take advantage of that?

Unless the 103 is damaged, I don't think I'd bother with an 104 upgrade, a lot of effort for a few horsepower that probably won't be that much quicker.
 

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2003 Mercedes SL, 1964 Corvette StingRay Sport Coupe, 1992 Mercedes 300 SL, Porsche 911 Twin Turbo
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Discussion Starter #6 (Edited)
Sure the block is not the same? If you take the head off a M103 and M104 engine all you see the top of the 6 pistons
The difference is the cylinder head not the engine block i think

Anyway a M104 engine is not pricey at all


The M104 is a double overhead cam with 4 valves per cylinder - you only have 2.

Different setup.
 

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Administrator
1998 Pano SL500; 1993 SL500; 2005 ML270cdi
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Transplanting engines (different) requires a lot of mechanical and electrical ability.

A very well tuned 103 would not be that much different from a 104 engine.

As stated above, if you are seriously considering an engine swap, go for the M119 and all the electronic headaches with it.

Personally I would do a really good job on the M103 head, or sell the car and get one with a V8, which would probably cost the same or even less than a properly executed engine swap.
 

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2003 Mercedes SL, 1964 Corvette StingRay Sport Coupe, 1992 Mercedes 300 SL, Porsche 911 Twin Turbo
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Discussion Starter #8
The M103 in my car is tuned very well and have a newly restored cylinder head(was restored last summer)

I have not driven a M104 for quite some time but i remember that the M104 was quite a bit more willing on power than the M103

The reason i bought a M103 was because of all of the problems you have with the leaky cylinder head on the 104 but you have that on the 103 as well

If i change the car for a 500 it will be the R230
 

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2003 Mercedes SL, 1964 Corvette StingRay Sport Coupe, 1992 Mercedes 300 SL, Porsche 911 Twin Turbo
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Discussion Starter #10
Perhaps a SL from 2007 or newer then :)
 

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SL's & 500E's
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SWAP?

Perhaps a SL from 2007 or newer then :)
I'll swap ya my 99 SL500 w/Pano for your 64 Coupe, I'll even pay shipping both ways... ;)
 

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2003 Mercedes SL, 1964 Corvette StingRay Sport Coupe, 1992 Mercedes 300 SL, Porsche 911 Twin Turbo
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Discussion Starter #12 (Edited)
I have had the StingRay since 1993 so it is almost a part of the family :)

A 1968 Corvette is a nice car. I have been looking at several this summer so am thinking of buying a 1968-72 Corvette but i have to find a nice car

A C3 with rust issues on the birdcage is something that scares me a bit

There is a person that have a mint Ferrari 348 TB that have asked me several times if i want to swap cars with him but no that will not happen

If it was a Testarossa i would i think
 

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SL's & 500E's
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I have had the StingRay since 1993 so it is almost a part of the family :)

A 1968 Corvette is a nice car. I have been looking at several this summer so am thinking of buying a 1968-72 Corvette but i have to find a nice car
In your year range, I would look more towards the 72 as I think they had fixed some of the early C3 design problems by then. I owned a 69 coupe, nice looking car, but it had several problems that drove me nuts.. Little or no insulation between the engine and the foot well, my feet used to be hot all the time. the doors had a slow rain leak down low, if sitting in the rain for a few hours, the foot wells would collect water. The T-Tops squeaked and rattled, sounded like a truck at times. Plus most 68-69's had high compression motors, 10.5 or so, needing 100 octane leaded gas back then. What kind of gas would you run in one today? Those old cars don't have computers and anti-knock sensors to run the engine timing.
 

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Discussion Starter #14
On those old V8 i use regular 95 octane gas with lead substitute
Most say that the lead substitute does not help but i always use it
 
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