whats achievable of a 77 300D - PeachParts Mercedes-Benz Forum

dieselholic · #1 08-14-2014, 08:00 AM

Hey everyone, im new here and new to the mercedes world. I recently picked up a 77 300D for pretty much free and come to find out the motor is stuck. Long story short its going to need an overhaul. Now before i stick a pile of money into this thing i want to find out what its all about. I have seen these videos on youtube where these guys are making some pretty good power with these cars and i have a few questions. How much power can you make with a om617 and keep it reliable? Are these guys swaping in different motors? I heard it is very expenseive to build a car like this, is it true? And what do you have to do to the rest of the powertrain to make it hold up? sorry for so many questions at once! any input would be greatly appreciated.

-Thanks

Simpler=Better · #2 08-14-2014, 01:02 PM

For an NA 617, you're probably looking at a maximum of 130-140hp (ISH) with a properly setup turbo, and the proper tweaked injection pump.

Best bang for the buck is to:
-Adjust your valves properly
-Check your timing chain stretch and correct/replace
-Get your injectors balanced with new noxxles
-Advance your timing slightly

dieselholic · #3 08-14-2014, 03:29 PM

so im guessing that those guys are swapping different motors from something newer?

DieselPaul · #4 08-14-2014, 05:03 PM

Yes and no.

Some are swapping to 601/602/603 2v motors, some are even going to 604/605/606 4v motors, but people have made good power with the 617, however the distinction is your motor is an N/A. The turbo motors have different internals, head is a bit different, injection pump is different, and the turbo motor has oil squirters.

Expensive to do? In my opinion no, but its also not a modern EFI turbo car when you can chip it and be done.

I think injection pump performance builds are in the $2,000-3,000 range with shipping and exchange rates. Back when I messed with turbo cars and friends had supras, dsms, etc, if you did a set of injectors, fuel pump, regulator, and a way to be able to tune with quality parts you could easily spend $3,000. In your diesel that's all pretty much contained in the pump.

Then you need a big turbo and an intercooler.

How much power you want to make depends on how much you want to spend. Bigger turbo means bigger intercooler, do you want a custom equal length turbo manifold, more $$$, etc.

Dropping a turbo on an N/A 617 and spinning the full load screw isn't really going to do much but melt pistons while making 130hp.

47dodge · #5 08-14-2014, 06:49 PM

If needing a rebuild I would start with the 617a turbo then build that. I have a long block I need to get rid of. Was running when parked. Turbo and manifilds are gone to another project, otherwise all there.

dieselholic · #6 08-15-2014, 07:44 AM

so if i were to start out with a turbo version, then what are my power limits? and what are these guys doing to the rest of their drivetrain? will factory stuff hold?

Skippy · #7 08-16-2014, 07:15 AM

I haven't done any of this stuff, just repeating what I've read: The stock pump on the turbo versions will flow enough fuel to make 150-160 horsepower with the rack limiter removed. You will need greater than stock boost to burn this much fuel without melting things, at which time an intercooler is highly advisable. If you spend the money for bigger pump elements, a big turbo, and a big intercooler, I've heard that stock internals can take 450-500 horsepower before stuff starts breaking. Unless you're made of money, I would suggest doing a lot of research before you start trying to make big power.

Phillytwotank · #8 08-16-2014, 10:43 AM

How big is your wallet?

Truly maxing out a 617a just doesn't make economic sence IMO. A stock 617a with the boost turned up is fairly thrilling but far from MAX.

The cost of that big pump,big turbo,inter cooler is going to be so high and require so much work one might as well just get a stock om606 car.

winmutt · #9 08-16-2014, 04:38 PM

You can put 8mm elements in a MW pump on a 617 and put out decent power for $1200 pump. There is a states side guy doing dieselmekens elements now. And Tomnik lurks around, he has upgraded elements as well.

Personally, my 83 euro NA 300d w manual trans was a great car to drive, plenty quick and had no problems going to 95mph. Maybe you should start looking at doing a manual trans conversion if you feel its a slug?