Anyone ever do a 500sec makeover to your 300sd?
 

Its Albass man thats got the 500sec ,Ive seen pics of some transormations on youtube.It looks like a bolt up job ,would this be correct?My purchase last month of an 85 300sd with a front end needed has me thinking why not, its been disasembled and ready for a makeover.

I'm pretty sure it's a bolt on procedure, wouldn't you need the coupes fenders, headlights, turn signals, hood, and bumper, possibly more. I'm not sure, but I've been wanting to do this for awhile.

It so stereotypes the car as a wannabe.

When C-Class 4-doors from the mid-'90s started doing that - well, you just roll yer eyes at 'em and shake yer head.

What would be really cool is a 500sec OM603 conversion for a W126 coupe!:)

I have seen those done and for sale on ebay, but I have never seen a very clean conversion. Most are crude.

And while I love my 617, a 603 would move a coupe down the hwy better.

I think it is personal preference, the owner of the car shall decide what to do with it, but like someone stated, most of the time its not done properly.

Hi Guys,

I've been observing for a couple of month, but had to register to when I saw this topic.

What do you mean by done "properly" and "crude?"

4thesporty, what did see on ebay and what issues do you think made them dump their car on ebay.

Two months ago, I just acquired a 300CD and love it. I've been looking very hard for the right W126 SEC with hopes to eventually swap with a OM617 engine. Perhaps a OM606 from a E300D ('98 or '99), but read somewhere here that the fuel system could be too complex for me to tackle.

Thanks in advance.

Couper, you can put the OM603 pump on the OM606 to simplify the installation.

I have seen a couple on ebay, the problem's they have can probably be sorted out pretty easily, it's just not done before they decide to sell at an inflated price.

Usually it is a ragidy old sec with poor paint/bodywork and worn interior and the diesel is installed but the gauges don't work, or it wont shut off with the key, or the rear end drive ratio is not conducive to a diesel, etc, etc.

I've never seen one that made me go, "wow, that is a nice car"

This doesn't mean that it can't be done, but I haven't seen one done in the manner that I like. If you were to do it yourself, you would probably find out in a hurry that the expense of doing it right would mean more money than the car is worth. That is why most for sale are not complete and the sellers are trying to re-coup some of their investment.

JMHO.....

^ Great way of putting it.

The last "SDC" I saw was a 617 into a 560SEC with V8 rear gears, the car had been hit and poorly rebuilt, the paint was poorly done. None of the wiring was loomed, it just seemed to hang all over the place, there were exposed butt-connectors, and the interior was scary, tons torn leather and exposed foam. But the car got 35+ MPG and was easily worth his $8k asking price. (insert sarc-mark)

Great Insight: Thanks
 

Thanks for the great insight guys. I'm close to abandoning this "dream."

I did consult with a new friend who was a long time professional MB mechanic and now restores collectible Posche for a living. He was very optimist about the swap and thought it would be "easy." ( Perhaps for him.)

Not once did he consider the V8/Diesel gearing issues. I guess he is only experienced with gassers and increasing HP engine swaps. What would be involved to address this challenge?


I am with you guys and I would only do this with a very clean inside and out MB. I have been actively shopping for a W126 SEC. With your help, I will probably direct this energy to finding an even cleaner 300CD than my current one.

I am by no means an accomplished DIY'er. I do attempt to do everything myself because of cost, trust and workmanship issues.

Adam, to do it right, what types costs would I incur?

I hope to gain a little more insight to finally put this project to rest. It's has been hard to be realistic and objective.:confused:

To be honest, I'm not sure what kind of costs you would be looking at.

My observations are just of the ones I have seen and I drew my conclusions based on that information.

There are other problems with converting gas to diesel to consider as well, such as registration. My state(TX) does not do emmisions testing on diesels and I'm sure if they were to hook up the machine to a 617 or 603 from the late eighties it would not pass.

Some states will not allow you to put a diesel into a gas car.

Again this is all things I have seen in passing.

I don't want to discourage you from attempting it, but it is worth noting the problems(challenges) that go along with the project.

If you do succesfully do it, please post pics here.:)

Thanks Adam. Your observations and insight is what I'm looking for. I have a limited amount knowledge about diesels, MB's and mechanics in general. I've just begun to learn more when I got my 300CD and thought about the swap.

I suspect that the driveshaft/gear issue would be the deal breaker. I didn't consider the proper gearing would be need for the diesel and that I suspect would require a some customization. A challenge and cost I'm not willing to incur. I doubt the driveshaft of OM617 or OM606 will bolt up.

What do you think?


I'm in Los Angeles. Diesels have always been exempt, until this year, when 1998 and new are now tested. I rationalized the smog testing requirement by hoping I could get a DMV "referee" to exemept the car as an older diesel. I did not find anything about diesel swaps being prohibited. Engine swap in general are discouraged, but not prohibited.

I am attempting to understand all the challenges. Perhaps I need a little discouraging and dose of reality as my budget and skills are limited.