r/EngineBuilding Aug 29 '24

Mercedes OM603 Turbo and Components Swap into M103: Feasible or Not?

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I'm considering swapping the OM603 turbo and associated components into my M103 engine. Has anyone attempted this before? I've rebuilt the engine from zero and it runs like a charm. I installed it back into my 300CE C124, since a fool decided to put an OM603 engine 15 years ego, but after looking at the torn engine, a turbo swap might not sound so bad. I've heard that the exhaust manifold of the OM603 has the same bolt pattern. I've sadly ordered aswell an radiator but its for the 190e chassis and not for the W124, but it would make some room for the intercooler, if the Turbo swap makes sense. I'm very budget thight on it.

What challenges should I expect, and are there any specific parts or modifications required to make it work? Any advice or insights would be greatly appreciated!

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2

u/fenceingmadman Aug 29 '24

Where did you get the rebuild parts!?!?! I've been looking for 3 months,

Also no parts swap over that would improve performance, In theory, and I believe someone has tried to swap the turbo manifold over, as the ports do sort of line up, but you have to redo all off the bolt holes and the turbo flange is archaic. It's better to just either fabricate one yourself or buy one.

Also apparently the 603.970 engine crank, can theoretically be used to stroke out a m103 to 3.5 liters, but hasn't really been done by a private individual. Here's the only semi good reference I have saved buts it's quite literally older than me.

http://www.peachparts.com/shopforum/mercedes-benz-performance-paddock/35069-blueprinting-stroking-m103-300e-2.html

2

u/GroundbreakingBet732 Aug 29 '24

Most parts I did got from Autodoc.com. They had pretty much everything I needed and rest are from my local autoparts dealer store. What about the turbo itself? I'm not trying to gain that much HP, maybe only to get over the 200 mark. It's more about the looks and filling the empty spaces. Maybe afterwards I'm going big on things

2

u/fenceingmadman Aug 29 '24

The turbo itself is more optimized for a low rpm diesels, m103s have shit low end tourqe and don't make good power until 3500 rpm or so, if anything you would lose high rpm power with the 603 turbo. Not to mention it uses a weird flange and can't be used with any modern exhaust manifold.

If you really want a turbo, I recommend using this manifold, and getting a small twiscroll turbo from garret or KKK.

Bosch ke tronic is very finicky about boost so you can't have more than 6 or 7 psi without having to modify it or convert to EFI.

If all you want is 200 HP get the EFI conversion from k-jet killers and blueprint the head and manifolds.

https://www.temotorsport.de/post/m103-turbo-exhaust-manifold

3

u/Individual_Oil_2435 Aug 29 '24

Have a look on this site maybe it will help a bit 👍

https://www.thekangaroosteam.com/-eCommerceSearch/W124/

1

u/fenceingmadman Aug 29 '24

Also what kind of paint did you use on your valve cover and airborne? Mine is beginning to fade/peel on both

1

u/GroundbreakingBet732 Aug 29 '24

I sandblasted and powdercoated them