Hi Don,a good 'basic' book is the Haynes manual for your car,I don't think anyone has made a 'dummy' book for the Mercedes,probably just for VW's:D .Anyone know of any other basic manuals available?

Don,

You said you revved the engine then took a run at the ramp. Then the engine almost died when the car tried to climb the ramp. Sounds to me like a governor issue. The governor is supposed to sense the increased load (skinny passengers have no bearing here) and increase the fuel to the engine. Your car will just about idle up a steep ramp once it gets rolling - if the governor is working right.

Leathermang's mark and rotate method is how we "recalibrated" speedometers in our old race cars when we couldn't afford tachs. Still the best way to determine the ratios.

Thank you all!

Basically, I have decided to do the 'test' described above and to have the engine timing, chain etc. checked, and to have the injection pump looked up as well.

Once all these are done, I'll bring them skinny friends with me again to the same spot and then test the car.:)

I'll take some pictures of that darn ramp too and paste it here coz maybe it might really be abnormal.:)

tnx!

-Don

Testing smeshting!
 

Don,

Before you do all this testing, crawl under the car scrape the gease and dirt off the flat area on the bottom, left of the differential and read the numbers. I've very little doubt that you've either the turbo rearend of 3.07 or even worse, you managed to find a rearend out of a wagon that's 2.88. After reading more of your thread, I'm beginning to vote for the 2.88, in which case it's amazing that the car with so little power, so much weight and skinny firends moves even on flat surfaces.

At the very least your rearend ratio should be around 3.46. give or take a few numbers on the right side of the decimal point.

Take a crawl, you'll be happy that you did!!

Ben

Don, here on the other side of the world,, we would like to know the grade of that ramp... if it would not be too much trouble...:D

I think our steepest roads are in SanFrancisco... someone here will know what the record is... that would sure be bad to be out in unprotected traffic and not be able to make it up a hill... :eek:

the tire/driveshaft measureing is the most reliable test of the ratio , no chance for error.... the serial numbers would not tell you if someone had changed the gears inside the third member.. ( not at all likely... but is possible ).Greg

Ben, what model would have had the 2.88 ? Must have had a big engine... or lots of gears... all the 123 turbos that I can find listed seem to have the 3.07 rear.... which of course is still way too high for Don... :cool:

2.88 Rearend Ratio
 

leathermang,

The fellow that I helped convert his 300TD from automatic to manual 4 speed has a 2.88 rearend ratio. That's the wagon. Both of us found it strange but it really cruises at low RPM on the freeway. Of course it must get a little breathless on long grades.

Ben

What year wagon was that ? Was it a 123 ? Did you measure it or did you find that in some literature about the car ? Greg

2.88
 

leathermang,

That's a 300TD, 1985 wagon and we know it's a 2.88 because the number is stamped in the differencial housing and it doesn't get any higher than 2700RPM at 70MPH. And that's with a manual 4 speed. Why, are you looking for that ratio?

Ben

I was just trying to figure out why my $200 worth of Factory Shop Manuals did not list that as a possibility... they show 3.46 for the non turbo and 3.07 across the board for 123 Turbos... Was that a European issue car ? Greg