Living with a Greasecar, part 9.....the final chapter.....

Cotton wrote: I've always enjoyed your greasecar threads. I would love to use this process on my 12v cummins or 6.2 blazer, but just haven't had the time.

I'm thinking of replacing the W124 with either a dodge or a 'burban. Those are the mileage kings in the tow/haul worlds.
Really, just budget a weekend (maybe a long weekend) for the conversion. Once you get your filtering setup ironed out (took me a few months to really get the bugs out) the time in the garage is minimal, under an hour a month for the 50-60 gallons I was burning.

The grease can be hard on the cars and in my experience maintenance on veggie cars is often neglected. I've never had a w124, but I've had around 10 older Mercedes (mostly w123s a w126 and a few R107s) and have never had any major issues, doing all of the work myself on them. The last one I sold, the w126 I got for $500, put maybe $1000 into over the 3 years I daily drove it, and sold it a few months ago for $2000. In my experience they are simple and easy to work on cars.

when my father converted his grease car jetta back to regular diesel.. he was having some turbo trouble. Not sure if it was the grease or not.. but the intake on his car was compleatly choked in carbon

DrBoost wrote: Once you get your filtering setup ironed out (took me a few months to really get the bugs out) the time in the garage is minimal, under an hour a month for the 50-60 gallons I was burning.

Sorry to hear of your frustration. I have enjoyed following along. I initially thought your frustration would come from the oil/fuel collection but that seems to not be the case.

bgkast wrote: The grease can be hard on the cars

That's only if you are doing it wrong. The fuel needs to be clean. Most diesel fuel filters are good to about 12-15 microns. I filter my oil down to about 1/2 a micron, human hair is about 70 microns.
The oil has to be dry, my oil exceeds water levels for North America and European standards.
The oil has to be at lease 165F when switched over. I'm always that high or higher.
If you don't do it right, then you start tossing pumps, injectors, and/or cylinder walls.

I was in a production brewery the other day for a project where we are removing a large centrifuge and thought of you and your processing set up. All pretty, stainless construction and built like a tank (used for separating yeast for reuse).

The downside is the 200 hp motor that spins the thing...

I have a diesel w126, and it is probably the easiest car I have worked on. i bought it with ~400k miles on it and it has been fine driving it for a year. The only non diy part I have come across it the lower ball joints, which require a $1000 special tool to install, but I had a shop press them in for $100 when I rebuilt the suspension. I dont think I would buy anything other than a om616 or om617 w123 or w126 and expect it to be as easy and cheap to keep running though.

mad_machine wrote: the intake on his car was compleatly choked in carbon

I think that's just a VW diesel thing. Didn't hey have issues with the EGR?

DrBoost wrote:

mad_machine wrote: the intake on his car was compleatly choked in carbon

I think that's just a VW diesel thing. Didn't hey have issues with the EGR?

Yep. In stock form, you generally have to clean the intake manifold and EGR valve every 100K or so. Which reminds me I need to get my original manifold cleaned before I do the 300K timing belt this Fall. It's amazing how choked up the manifold can be soimetimes and yet the engine will still run.

The coking is caused by the oily PCV vapors combining with the hot EGR gases. It can be helped some by either shutting off the EGR via VAG-COM programming (although this typically hurts mpg for some reason), or installing an aftermarket oil separator between the valve cover and the manifold inlet.

The carbon buildup can be an issue for all wvo burning diesels. The old Mercedes engines take to it better than others, but there are still issues: fuel viscosity, fuel system rerouting, etc. I designed and built my own heated two tank system, but was not happy with the fuel and pulled it after a few months.

bgkast wrote: The carbon buildup can be an issue for all wvo burning diesels. The old Mercedes engines take to it better than others, but there are still issues: fuel viscosity, fuel system rerouting, etc. I designed and built my own heated two tank system, but was not happy with the fuel and pulled it after a few months.

The fuel viscosity is easy to deal with. Heat the oil to 165 or higher and it has the same viscosity as diesel. I use my coolant loop to heat the oil. By the time my engine is up to temp, the oil is over 165.
The fuel lines are some work sure, but to me it was a great trade-off. The fuel and coolant lines are done one time. That trade-off is that you won't have to perform a science experiment in your garage to make bio.

I'm not sure about the w124, but every conversion for the 61X engines that I have seen (other than the one I made) switched up the stock routing of the lift pump, fuel filter, injection pump and return lines which in my opinion causes issues and potential damage to the fuel system...not something you want with one of those mechanical computer BOSCH injection pumps.

I can't comment on the computer-controlled stuff. I know the Merc engines are THE most forgiving for veggie conversions. Lots of guys have 100K+ miles on veg, I've got 73,000 veggie miles with no ill effects at all.
Explain the issue with the fuel routing damaging the pump. You have fuel in, then out, then returned either to the pump or tank. Does it matter that it goes through valves upstream?

On the 617 the stock fuel routing is pre-filter> lift pump> main fuel filter > injection pump > return line. In most of the conversions I have seen the kit rerouted the system putting he main filter before the lift pump causing the filter to be in suction instead of pressure and causing the lift pump to pull against much more of a resistance than stock. Some kits also run a returnless system where the fuel not used by the injection pump is routed back to before the lift pump. This not only can cause issues with air building up in the fuel system and starving the engine of fuel, but in my opinion also can cause issues with the injection pump due to the non-stock pressures created up and downstream of the pump.

My 84 300SD is easy to work on but the AC/Heat crap is horridly expensive and neither ac or heat works. Mechanically it works great and parts arent too bad as far as expense. I have thought about using the veg oil but havent gotten to it yet. Have to replace the rubber lines soon anyway. Used trans arent bad, can even find complete running cars for cheap to for extra parts. My car is an older version so maybe the W124 is harder to work on or around but theres lots of room in there and the thermostat is easy to get to. Dont give up yet, sounds like you fixed the worst of the stuff already.

I had SO many customers with 123/124 cars with trashed AC vacuum actuators... there were a lot of them where we rigged up cables and blocked off the vacuum stuff. Not perfect but at least you could have working defrost for less than $1500.00.