123 240D GP relay
 

I've got a pre 1980 616.912 from a W123 in my '75 115, someone did a nasty conversion from the previous 230, including a horrible job on the glow plugs (on a timer, takes 2-3 minutes to glow). I'm looking to replace the relay but not sure what realy I want. MB is not helpful (they can't do anything with the engine number and I don't have the chassis number of the donar car), and parts shops want the relay part number.

So what relay does a pre 1980 W123 240D use? It's got the loop type glows, which I'm replacing also, they're getting rare over here (UK) but have found some.

I use a manual relay. A basic toggle switch, glowplug light, 80amp relay, fuse and wire is all you need. You can browse through "Fastlane" at the top of the webpage, it lists most every part available.
http://catalog.worldpac.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=2BA0V8YNJ2BK0D328Q&year=1980&make=MB&model=240-D-002&category=All&part=Preglow+Time+Relay&appChassis=_any

Could you post some pictures of the conversion? I know there are some people that would be interested in using a later engine in their W115 240D.

If you have a push-pull knob,you don`t need the relay,just keep things simple...
Are you sure you`ve got any relay at all??
if you insist on having it,check the manufacturers` catalogues for original relay part numbers:
http://www.beru.com/english/produkte/produktfinder.php
http://www.bosch-automotive.com/ecat-online/
www.autoteile-shopping.de
Get rid of the series glow-plugs and get an upgrade kit from Bosch:
0 250 201 955
Kit Includes: 4 Glow plugs, 0 250 201 044; 1 Control Unit - 0 281 003 005, 1 Service Kit = 1 235 345 001 - Nut; 0 332 002 156 - Relay; 0 354 010 001 - Fuse Holder; 1 904 520 017 - Fuse;
...or just buy 4 glow plugs Bosch 0 250 201 044 or Beru GV 626 (0100221311),or buy the simple non-relay kit SR 002 from Beru(page 41):
http://www.adpdist.com/beru_glowplugs_application_na2004.pdf
http://www.carparts-cat.com/nl/webda...0221%20311.JPG
...make jumper wires(min.6mm.sq.) ,replacing the resisror wires between the plugs and get rid of the grounding cable from plug 1 to the cyl.head:
http://www.dieselgiant.com/mercedesdieselloopglowplugrepair.htm
http://www.dieselgiant.com/glowplugrepair.htm
The car will start much easier...

Make sure the toggle switch is spring-loaded to the "off" position!!!

I have a "push button" switch in place of a relay on my 79 240D. Its 15 amp and runs through a Ford solenoid (which you dont need if you stick with the old style GPs). I would highly recommend upgrading too the new style tho. The switch is mounted low on the dash, above my left knee, (5/8 hole) so I can push it with my left hand and turn the key with the right. Works great.

thanks for the info guys, I'll try a high amp switch. Only problem with a switch over a relay is this is a RHD car, so the GPs are over by the passenger, so that would mean running those big hot wires a long way... I guess I could put it over by the passenger and lean over.

I've already got new loop injectors on order, wish I'd got that info a day earlier! Never mind, if I get the glow time still gives me the 5hits I'll change them over.

As for photos of the conversion, I could take some phone ones. It's not pretty though, you wouldn't want to copy it. The biggest problem seemed to be how far back the motor sits - the front cross member interfeared with the sump - a small amount of webbing was removed. And the oil filter has a recess hammered into the firewall for it, but is still close - to change it you need to remove the heater hose mount, and it's still hard to do.

The exhaust is also a nasty job, very low clearence - with a heavy load you bottom out over medium bumps. You don't want to follow this conversion... Might start looking for a clean W123 240D sometime soon.