Pagoda SL Group

W113 Pagoda SL Group => Research & Development => Topic started by: redpagoda on September 05, 2006, 18:54:01

Title: Converting Rev counter mech to elec??
Post by: redpagoda on September 05, 2006, 18:54:01

I am converting my 250SL, with an engine transplant into a 1990 300e drive line. All is going well with no engine bay surgery. Only problem is old tachometer is mechanical and new engine only has electrical output. I am not wanting to change the physical appearance and wish to retain the original instruments. Any suggestions

Title: Re: Converting Rev counter mech to elec??
Post by: ja17 on September 05, 2006, 19:15:55

Hello Red,

The latest version of the Mercedes 280SE W111 coupes and conv. used the same size and style tach. It was virtually the same except that it was electronic or "electrical" and had no mechanical cable. This may be your best option if you want to stay original looking.

Joe Alexander
Blacklick, Ohio

Title: Re: Converting Rev counter mech to elec??
Post by: psmith on September 05, 2006, 23:18:56

Hi Red,

I would be interested in hearing more about your project.  Did you keep the original suspension/steering/breaks?  How about the transmission?  Post some pictures if you can.

Pete S.

Title: Re: Converting Rev counter mech to elec??
Post by: waqas on September 06, 2006, 11:41:48

Hello Joe,

Did the earlier 250se w111 coupes also have this?  My '67 250se coupe does not have the tach drive fitting on the engine (the casting explicitly shows 250 on the driver side), so I suspect the electronic variety.

How does it work? Where does it attach to the engine?

Cool project, RedPagoda. I'm sure there's lots of folks interested in the outcome of your experiment.

WAQAS in Austin, Texas

Title: Re: Converting Rev counter mech to elec??
Post by: redpagoda on September 06, 2006, 17:24:30

I will be happy to post pictures upon completion. We are trying to use the 300E radiator and oil cooler. Choosing the pre 92 300E meant the wiring modifications are simpler with no computer to worry about, only the ecu management for the EFi. I also gain integrated AC. The bigger question being whether the ABS can also be used.

The original exhaust virtually marries to the new exhasut manifold. by reversing the linkages the auto gate will work in the same order as the original

The primary under bonnet appearance change will be the air filter, and to fill the void of the original airfilter I am doing away with windscreen washer bag and installing the 300E plastic resevoir. Retaining the original brass raditor resevoir and as many other original components

1967 250SL

Title: Re: Converting Rev counter mech to elec??
Post by: 114015 on September 07, 2006, 16:40:40

Hello tach admirers,

The electronic revolution counter was introduced anytime during the production run of the 250 SE Coupé. All 280ies (W111 - 6 cylinder) had that one as well. The 3.5 has a different instrument (for 8-cyl.)
Try the ususal used-parts-supplies for this rev counter. There is numbering on the male plug on the rear of the rev counter which corresponds to the ususal MB electrical wiring system numbering (light, ignition, etc.). You will then find where which connector pin goes.
Good luck!




Achim
(Magdeburg, Germany)

Title: Re: Converting Rev counter mech to elec??
Post by: hands_aus on September 12, 2006, 05:10:55

Hey Red,
Is the 300E a V6 or straight 6?
What prompted the change over?
Don't mean to be a sticky beak, just interested as I have a 250 sl also.
I think the whole group would be interested in the progress of your project. Pics are always welcome.
Mechatronic has been discussed many times.

Bob Smith (Brisbane,Australia)
RHD,1967 early 250 SL, auto