I posted this topic in the Peformance Paddock, but wanted to also get this in front of the Techs for comment. Any help is greatly appreciated.

I'm considering the replacement of the M104 engine in my 1990 300SL with an M119. I have access to a 1998 M119 engine complete with harness and brain... and with transmission if I need it. This came from a 1998 SL500.

My interests are to boost HP and torque and I plan to hold on to the car so impact to resale value is not a concern.

My questions are related to what needs to change with the swap.

1) Will the existing 722.500 5spd auto work with the M119?
2) What are the interfaces required between the 1998 brain and the balance of the cars electronics?
3) Would the fuel delivery system require upgrade to work with the M119 sequential injection system.
4) Would I be better off finding 90/91 M119 controls/injection/induction for compatibility.
5) Would the radiator in the 300SL be large enough for the M119.

... and any other considerations helpful to support this probably insane plan

Thanks,

Wayne...WOW...

I see that you do not want to change the head gasket on your current leaking engine :D . I just took off the head of my 1990 300SL-24 today to get the engine to keep the oil where it belongs.

I think that changing the current engine to the M119 engine involves a lot more as one might think...The newer euro MB models do not want to run at all as soon as the engine and...lets say...dash cluster are separated. The data is not only saved in the computers of the car, but is stored in parts like the dash cluster as well.
I think that the 500 suspension is different as the 300 as well and I think that your current transmission will not fit the 500 engine (different flanges).

good luck & greetingz,

MBenz,

I completed the head gasket work on the M104 complete with new valve seals just for good measure. Everything worked out fine. I noticed that the new head gasket had copper reinforcement around the oil passage on the back corner and the original did not. I hope this allows the gasket to hold up for a while.

The M119 opportunity just came up at the same time... I would not do the conversion until next winter, but am interested in the possibility.

When you mention that the car does not want to fire after a conversion because of data storage, what is the nature of that problem. As far as the trans incompatibility, I do have access to the auto that goes with the M119.

Thanks for the info,

See my reply in the Performance Paddock.

:-) neil

Neil, I saw your reply. I knew you took on a similar conversion. I'm up for some significant work, but 1/2 a man-year is a bit much!

In looking through the documentation I have, it seems that the suspension, brakes, and crossmembers are the same, excepting spring rates and sway bars. The big unknown to me is the electrical integration that you mention.

I guess I need to reconsider,

Thanks for the feedback!

Best of luck.

I would double check with the dealer regarding the front brakes.

Ask for rotors & brake pads for the 300SL vs the 500SL.

There should be a difference.

Best of luck.

:-) neil