Update on gas mileage - 1982 300D/4.3L Conversion...
 

Hello all,
Some of you may remember reading about my 1982 300D that I installed a 4.3 liter Astrovan V6 in - I have driven it for about 8 months now, and have taken several longer trips with the car, so I can now report that with 4 people in the car it will produce around 28.5 mpg, cruising at 80 - 85 mph with the A/C on. It gets around 21.1 mpg in average around town, go to work driving. I think this is fairly comparable to a diesel engine in the same body, so I'm very satisfied with it, since it has much more power than the diesel did, and the engine rpms are a lot lower so the engine is very quiet. (around 1650 rpm at 60 mph, 2960 at 100 mph.)
If you are interested in reading about the conversion you can view my report at: http://pages.prodigy.net/rwooldridge/mercedes.htm
One bit of information not included yet is that you can get the right pan for the conversion from an engine in a 4wd S10 or Blazer. Turns out that they use a pan that's pretty much identical in appearance to the mod I performed on my pan.

Richard Wooldridge
'82 300D/4.3 L V6
'74 280C
'77 XJ6L
'77 280Z
'88 Astrovan
'85 GMC S15

Thanks for the update. Yours was a fascinating project. As much as I like diesel technology every time I crunch the numbers on fuel costs there is not that much of a difference between diesels and electronically fuel injected gas cars. Around here diesel is consistently 15 to 20 cents higher, which almost offsets the difference in efficiency. Repowering could be a viable alternative for clean, older MB diesels with bad engines.

The gas milage you are getting is great. The best my 92 Chevy Astro gets is 20 Mpg.

The station wagon presents much less frontal area than a van as well as a much better aerodynamic coefficient. I wouldn't be surprised if the wagon weighs less than the Astro van as well. The tall gearing of the wagon probably works out pretty well also.

This is a man that obiously knows how to go about doing an engine swap.

As for the diesel comparison, once you have the MB diesel affliction, as I do, it's difficult to lose. To me the diesel stinks so good and it rattles so good. The incredible longevity of the MB diesels if properly cared for is great.

I compliment you again, Mr. Wooldridge, on a job well done.

Have a great day,

Hi again,
Thanks for the nice compliment, Larry! Yes, I think you are correct about the frontal area making a huge difference - I do notice that with our Astrovan there is a need to "keep your foot in it" at speed, and it has a lot of fan noise also. With the 300D/4.3 I hardly have to touch the pedal at speed, it just seems to float along. I think the 123 chassis is a very good design, aerodynamically speaking, and it's also a very comfortable design for up to 4 occupants. Our Astrovan also doesn't do nearly as well on mileage, but if driven carefully will give up to 24 mpg on longer drives with not too many hills and not over 70 mph. It has an entirely different feel than the Merc, though!

Regards,
Richard Wooldridge

The GM 4.3 is a pretty durable engine a kicks out a suprising amout of power. The 4.3 seems to have more power than the small v8,s suuch as the 262, 283, 307 and low performance 327s of the late sixties early seveties. I know, back in those days anything less than a 350 was scoffed at as not having enough power. Enjoyed seeing this conversion. Hope it lives long for ya.