Mercedes-Benz Forum banner
1 - 17 of 17 Posts

·
Registered
300sd 83'
Joined
·
489 Posts
Discussion Starter · #1 ·
I have an 83 300sd i want to stick the motor and trans in to a 90 420 sel besides the obviouse fuel tank, lines and gauge what else do i need to transfer? Is it at all possible?
 

·
Registered
83 500SEC, 87 300D, 92 190E 2.6, 02 C32, 02 C32T, 03 C320T4, 03 E55, 05 CDI, 06 CDI
Joined
·
2,601 Posts
driveshaft and trans support mount (if its wider etc, never tried it myself). shifter linkage
 

·
Registered
1983 Euro 500SEC AMG, 83 SEC custom convertible, 2x 84 500SEC, 02 w203coupe, euro 1985 300d
Joined
·
1,579 Posts
yes but the driveshaft in the sel is longer---all can be done though ---you are just longer in the a$$ end
 

·
Registered
300sd 83'
Joined
·
489 Posts
Discussion Starter · #5 ·
Can i mount the 300sd tranny to the 420 drive shaft?
 

·
Registered
'87 420SEL '89 300E
Joined
·
44 Posts
Why would you want to convert? Why not buy a 420 ready to go? Unless you just have a 420 engine and transmission laying around that you want to use as a project.

It is pretty complicated, besides the obvious fuel tank, lines and gauge, and the transmission mount bracket drive shafts maybe the rear diff...you will also need to get the engine electrical components like (and not limited to) ECU, fuel pumps, fuel distributor...

If you have a complete 420 that was more body damage than you want to deal with, but the engine and transmission are in good working order, I would get a smaller car to install it into like a w124 (300E) or even better a inline 6 w201 (190E). Any smaller, lighter car would do.
 

·
Registered
300sd 83'
Joined
·
489 Posts
Discussion Starter · #7 ·
Swap

I have a 300sd interior is shot but motor is Excellent
I have a 420 sel motor and trans not so good interior is Excellent
I love my diesel reliable and gets great milage there fore im thinking of swaping the motor out
 

·
Always Remembered RIP
1991 560SEC AMG
Joined
·
10,146 Posts
I like the idea

THEORETICALLY the idea rocks; simplicity and cast iron durability of the 300Diesel engine, going into the last generation 420SEL, with all the amenities they have (airbags, ABS, latest interior, smooth lower rockers)

As a practical matter, how costly to make the change? I always wondered why more W126 people who know the diesel engines didn't try this. Like getting the benefits of a '90 or '91 350SDL but without the headaches of the rodbender diesel engine....
 

·
Registered
1986 300SDL 311,500
Joined
·
287 Posts
IMHO the hardest part will be getting all the vacuum system transferred over, remember that the diesel uses external vacuum widgets instead of (absent) manifold vacuum to determine shifts.
 

·
Registered
300sd 83'
Joined
·
489 Posts
Discussion Starter · #10 ·
OOOh Forgot about that, But it is a very doable thing. the 420 everything is electronic such as doorlocks and trans etc. does any one know if this has been done
before?
 

·
Registered
300sd 83'
Joined
·
489 Posts
Discussion Starter · #12 ·
I would like to do as much as possible on my own but probably not I lack a lift.
 

·
Registered
'87 420SEL '89 300E
Joined
·
44 Posts
300sd said:
I have a 300sd interior is shot but motor is Excellent
I have a 420 sel motor and trans not so good interior is Excellent
I love my diesel reliable and gets great milage there fore im thinking of swaping the motor out
I mis-read and thought that you were installing the gas engine to the diesel body. That's my bad!

Why don't you switch the interiors out instead of trying to make the mechanial conversion? Also I don't know what kind of emmisions requirements you have (in Atlanta you don't test diesels), so if you put a diesel into a body that has a VIN that indicates that a gas engine is supposed to be there, you will probably have to go through some procedure to change the title and registration to state the conversion and eliminate the requirement to have emmission testing (will probably alter the re-sale value of the converted car, if you care about that).

So if you just switch out the interiors you will not have to deal with the "legal" matters. And you can really clean behind those places that don't get cleaned very often (or very well)!!
 

·
Registered
1966 250SE Cab, 1989 500SEL euro
Joined
·
3,570 Posts
I think this is a fantastic idea. A 603 or 606 long block is cheap and easy to come by - installed in latest model w126 is a perfect solution.
 

·
Registered
1983 300 SD; 2000 E320
Joined
·
1,099 Posts
I'd advise swapping out the interiors. You could achieve everything except airbags and pop-up sunroof.

If you do swap engines, the fuel tank could stay, just remove the fuel pump. Getting all the vacuum lines right for the engine and tranny would be difficult, but not impossible if you're a good mechanic and can take them all off your SD.
 

·
Registered
300sd 83'
Joined
·
489 Posts
Discussion Starter · #17 ·
Actualy changing the interiors was the original plan the motor swap seemed like a good idea until luxuryedition brought up a very valid point that the car would have to meet emisions. So the 420 will be gutted. I will install all parts from the 300sd into the 420 and then sell it cheap or donate it.

Thanks for all the help everyone.
 
1 - 17 of 17 Posts
Top