Following thread!

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w201 + m103.983 swap

This guy just did a 2.6 to 3.0 swap. Look at the cam in the pic, ack!

https://www.peachparts.com/shopforum/tech-help/397637-put-refreshed-3-0l-m103-my-moms-190e-2-6-a.html

Ouch those lobes are gone!

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Follow the team at:
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Current:
'74 450SLC
'89 190E
'95 E420

Previous:
'94 E320
'87 300E
'73 350SL
'75 450SL
'95 C36
'99 C43 55 swap

Only one lobe was flattened. There was some scoring on many of the lobes but nothing bad especially considering this was the soft cam. I sorta wonder if that particular valve was sticking or if the oiler was clogged at that point.

I didn't touch rings or bearings on that engine. All I know is it had over 200K miles and even with this flattened cam, the leak down and compression tests gave results within factory spec. The cross-hatching was still visible on the cylinder walls. Seems to have been taken good care of back in the day. We resealed everything and changed the timing chain rails. That's basically it.

I'm assuming an EFI conversion would incur penalty laps? These engines benefit immensely from better ignition maps at the very least. CIS can provide enough fuel, though going to EFI really improves the response.

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Current: 1975 450SEL, 83 300D, 88 Yugo GVX, 90 300D OM603 swap, 91 F150 4.6 4v swap, 93 190E Sportline LE 3.0L M104 swap, 93 190E Sportline LE Megasquirt, 03 Sprinter, 06 E500 4Matic wagon.

Have a look at my later post in the referenced thread.

That seems plausible. I may take the valve covers off of my other M103s and make sure those bolts are torqued properly.

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Current: 1975 450SEL, 83 300D, 88 Yugo GVX, 90 300D OM603 swap, 91 F150 4.6 4v swap, 93 190E Sportline LE 3.0L M104 swap, 93 190E Sportline LE Megasquirt, 03 Sprinter, 06 E500 4Matic wagon.

We could do EFI but that is a pretty big investment in both time and money and is something we'd look into for next year and weigh against just doing a 2.8 M104.


As for this engine it is a later m103 and the leak down numbers are good. So I'll be pulling the head, looking at valves, and probably adding some compression.

if you haven't already i would look into adjusting the WUR to richen the mixture up a bit. K jet tends to be a bit rich at idle and low speed and then lean out above 2000 rpm could help pick up a tiny bit of power. that plus optimize the intake as much as you can the maf plate is quite a restriction on its own so anything you can do to alleviate further restriction will help. you can replace the main pin in the WUR with a screw and nut to make it adjustable on the fly to help tuning instead of having to use a punch and disassemble it each time you adjust it. im not sure if the early 103 has a WUR or an EHA but either way you might be able to adjust the EHA to richen the mixture the same as a WUR.

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1985 300D om617: 8mm M pump 175cc 5200rpm, holset he221w @ 30psi, large A2W ic, compounds on the way.
KD9AFT
A&P

Our car is WUR I never thought of putting a screw in there. Great idea! We will be getting a wide band in it so I should be able to do something with that.

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Follow the team at:
http://www.forthesakeof.racing/
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Current:
'74 450SLC
'89 190E
'95 E420

Previous:
'94 E320
'87 300E
'73 350SL
'75 450SL
'95 C36
'99 C43 55 swap

I'd put a wide band sensor in the exhaust then have a regulator in the car for the driver to adjust. Just be sure to have a lean limit so the driver does not ask for more power and burn the engine down.

The 1980 SAAB 900 ( and probably other cars in the same era ) has a narrow band oxygen sensor and a buzz valve to fine tune fuel mixture so you might be able to adapt / make such a system to wide band input.

im more familiar with the K jet systems on Porsche motors. had to tune an early 930 it was 12.2:1 at idle and up to 1500 then rapidly dropped to 14:1 above that finally hitting 14.4:1 at 5000. im not sure how the 103 will respond but its the same system and components as any other k jet so it likely is quite lean off idle for emissions and fuel efficiency reasons. if yours has the bypass solenoid in the WUR regulator line like the M110 you might be able to build a basic circuit to control it yourself.

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1985 300D om617: 8mm M pump 175cc 5200rpm, holset he221w @ 30psi, large A2W ic, compounds on the way.
KD9AFT
A&P

The shape of the air flow meter cone has a major effect on A/F ratios. A long slow taper will have a richer mixture than a rapid taper. RE: A slow taper has less air flow area relative to plate position compared to a rapid taper so the plate must rise farther for the same air flow.

There's no WUR on the m103 models as far as I know. They're all KE-Jet with EHA's.

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w201 + m103.983 swap

Maybe I have the two mixed up. I have the black box on the fuel distributor. Tuning it was a project for next month.

The refresh is going well so far. Any tips on how to tune the fuel system to get a little more power? Adjustable fpr maybe? I'm going to work on a wideband 02 sensor.