M104 with manual trans in w123 - PeachParts Mercedes-Benz Forum

garyd75 · #1 02-15-2022, 04:51 PM

Has anyone done this
My m110 needs alot of machine work ect
What's the weak spots on those m104 and the 5 speed trans
Thanks

fonzi · #2 02-15-2022, 07:33 PM

What trans do you plan on using? What fuel and spark management system do you plan on using? Which m104 / oil pan do you plan on using? M104 were common in r129, w124, w140, and I’ve seen several guys with them in w201 also.

Frank Reiner · #3 02-15-2022, 08:01 PM

Quote:

Originally Posted by garyd75

Has anyone done this?
My m110 needs a lot of machine work ect
What's the weak spots on those m104 and the 5 speed trans
Thanks

Think of this as any other engine swap; neither the 104 or the 103 was used in the W123 chassis. Everything will be fabricated: mounts, exhaust, linkages, etc. Rather than 3.0-3.4L, step up to 5L; SBF.

rwd4evr · #4 02-15-2022, 08:31 PM

Have a good head? I have one (m110) that has a broken cam tower/box(whatever you want to call it). I think the bottom end is good.

Sent from my SM-G991U using Tapatalk

VaiFanatic · #5 02-21-2022, 03:12 PM

Quote:

Originally Posted by Frank Reiner

Think of this as any other engine swap; neither the 104 or the 103 was used in the W123 chassis. Everything will be fabricated: mounts, exhaust, linkages, etc. Rather than 3.0-3.4L, step up to 5L; SBF.

I honestly wish SBF or even some more classic Mopars got more love when it comes to swaps.

On the plus side, you do have plenty of room to work with!

Frank Reiner · #6 02-21-2022, 05:05 PM

Quote:

Originally Posted by VaiFanatic

I honestly wish SBF or even some more classic Mopars got more love when it comes to swaps.
On the plus side, you do have plenty of room to work with!

With the SBF the width clearance is improved vs. SBC, and the SBF is shorter than the OM617, let alone the M110.
The M104 is longer than the M110; radiator clearance may be quite tight.

Sugar Bear · #7 02-21-2022, 05:18 PM

M103 and M104 both share head gasket oil leaks as a weak spot. The M103 may take up less room, their CIS fuel management can be troublesome and valve guide/seals may need replacement. The M104 has quite a bit more power, its other weak spot is the biodegradable engine wire harness. IMO they are both great engines.

VaiFanatic · #8 02-21-2022, 07:36 PM

Quote:

Originally Posted by Frank Reiner

With the SBF the width clearance is improved vs. SBC, and the SBF is shorter than the OM617, let alone the M110.
The M104 is longer than the M110; radiator clearance may be quite tight.

I had actually toyed with the idea of swapping a 351W into something, but set those plans aside as I never purchased the shell that would have received that transplant.

alabbasi · #9 02-26-2022, 07:30 PM

If an M103 fits in a W126, it will fit in a W123. The M104 is not too different.

rwd4evr · #10 03-04-2022, 07:18 PM

Quote:

Originally Posted by alabbasi

If an M103 fits in a W126, it will fit in a W123. The M104 is not too different.

While that is probably true for an m104. That is not necessarily the case In every situation. A w123 is 2 inches narrower between everything inboard of the suspension than a w126. Should basically be as simple as making motor mount arms but you could run into exhaust issues or intake manifold clearance because of it.

Sent from my SM-G991U using Tapatalk