1978 Mercedes 300D help

[tractorface]

A co-worker just acquired a 1978 300D. Really nice car too. The thing is wicked evil slow and since he had previously taken a ride in a certain overfueled CTD :-laf he has asked me for help in getting the MB to well get out of its own way. It seems he is having trouble finding a knowledgable MB forum like our TDR.



This thing has the intake and exhaust manifolds on the same side of the engine but otherwise looks a lot like our beloved CTD.



-Any ideas on the TDR equal in the MB world? Most forumns for MB seem uninterested in performance.



-Any ideas on the limits of this engine.



-Can the beast be made to keep up with traffic?



We already converted this guy to a diesel head, now we just need to get him up to speed :-laf

 

[DarkRAM]

a quick google search...

and i found this.



http://www.benzworld.org/forums/forums/thread-view.asp?tid=1227985



The body style for the 300d (1976-1985) is w123. Pre 1982 are non-turbo and the posts 1982 aren’t much faster. The inline 5 cyl. is quite robust in its stock form, not sure how it would handle mild BOMBing.



http://www.google.com/search?hl=en&q=w123+AND+performance+upgrades&spell=1



Best regards,

 

[WDixon27]

one thing that helps is to get them to actually start off in 1st gear, when it's working properly you need to kick it in the butt to get into first, age and wear can get it so you don't even know first is there otherwise it normally starts in 2nd

 

[chuckwilson]

If I were your friend I would buy a manual for it and set the valves and the gov. linkage, If the gov. linkage has any play in the ends replace them and set it to spec.

 

[bgilbert]

100hp non turbo 5 cylinder. Pretty much a dog, decent 25mpg, but thats about it. Heavy too.

 

[tractorface]

He told me it was rated 100Hp. Whew hoo 25% increase just by posting on TDR :-laf I knew this was the place for answers.



So what is the problem here? Is it the indeirect injection or what? We turn up the fuel on our trucks all the time? Is the motor just not built well enough to handle any boost? I figured we could mess with the pump slap in a turbo from a newer model and away we go. Maybe get a special set of EDM's

 

[cruiser_2]

Tell your friend to have the prechanbers removed and cleaned, then get the matching glow plugs and glow plug relays. There are two different styles of glow plugs and matching relays. relays will interchange but not allow enough heat to really let prechamber to work well. Relays are espensive too.



the adjustment of the governor rod going back to the transmission is CRITICAL. Adjust it just like the service manual says and use a METRIC measuring tape, and don't convert the measurement to inches (will not work). Make sure your kickdown swithc under the pedal is operating too.



Also just for giggles tell your friednd to glow the engine twice and see if that helps. I have one that only responds to that and everything else is set up exactly as required by benz. I guess some of these old cars just have a few quirks.

 

[tractorface]

Ok. Progress. Anyone have a vacuum diagram (or know where to get one) for a 1979 MB 300D. Looks like the vacuum lines are misrouted and are causing a lowpower problem by constantly trying to close the shutoff solenoid. Apparently a mechanic had tried to fix a no shutdown problem for the cars previous owner. After the "fix" the car was extremely low on power. It seems the door locks and A/C may also be problematic due to the vacuum issues.

 

[DarkRAM]

tractorface



I picked up this on ebay a few days ago; it should cover everything to do with the 300d. When it gets here I let you know what it has in regards to the vac. system. I know there are a ton of baffles and bladders and the door locks have always been one of the more problematic vac. controlled systems on the car. Along with the cruise control.



http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=8003593305

 

[monkfarm]

I have a 1979 300D Wagon with a 1983 (turbo) engine. The Turbo makes quite a difference. Don't know what it would take to put a turbo on it, but I have found some interesting (similiar models on E-bay (with the turbo) that aren't too expensive with little things wrong with them.